Bwk Good Practice 2001
Short Description
Descripción: Ibstock guide to good practice - Brickwork...
Description
Fg2 November 2000
Guid uidee t o Goo oodd Pra ct ctiice
INNOVATORS IN CLAY
™
Choice and quality you can rely on service you can build on CHOICE and SERVICE - these are the two words which inspire us at Ibstock Brick. A choice built on our commitment to provide an evolving range of clay bricks to meet your every aesthetic, technical and planning need.
Th T he Ibs Ibsto tock ck Br Bric ick k Gu Guid ide e to to Goo Good d Pra Practi tice ce co con nta tain ins s ess esse enti tia al information on all aspects of building with clay bricks. It clearly describes how desired levels of brickwork integrity can be achieved by explaining the technical properties of bricks. It also suggests how specific design features and detailing can be incorporated to protect brickwork from adverse weathering.
Th T he Ibs Ibsto tock ck br bric ick k ra range co con nta tain ins s a wid ide e ch choi oice ce of fa fac cin ing g bri bric cks in a breathtaking array of colours and textures. We also produce imperial sized bricks to blend with older brickwork and Class A and B engineering bricks to satisfy the most demanding structural
For further technical advice and answers to individual design requirements, one phone call will put you in touch with Ibstock's dedicated team of design advisors and technical specialists.
requirements. All bricks are manufactured under ISO 9001 Quality
We have the widest choice of products, expert guidance and
Systems and to BS 3921:1985.
committed service. At Ibstock, we strive to make your job easier
Our special shape brick service provides solutions to every design challenge. Standard shapes to BS 4729:1990 or individual purpose-made shapes can be matched or contrasted with virtually any brick in the Ibstock range. At Ibstock we back choice with service. We are dedicated to helping you make the right choice by providing the soundest design and technical advice. The ultimate aim is to ensure that you design and build quality brickwork which will stand the test of time.
2
every step of the way, from answering your initial enquiry through to the completion of your project.
Contents Brick rick Selection ..... ......... ......... ......... ......... ........4 ...4 Brick Types And Textures Dimensional Variation Definition of Sizes Special Shape Bricks Brickwork Dimensions Compressive Strength Water Absorption
Insulat ion .... ........ ......... ......... ......... ......... ......... ......26 .26
Durability Sound Insulation
Brickw rickwork ork .... ......... ......... ........ ......... ......... ......... ......11 .11 Mortars
Th T hermal In Insula lati tion on
Good Si Site te Pra Practice ctice.... ........ ......... .......... ........29 ...29
Mortar Perform Performanc ance e Brick Bonding J oin intt Prof Profil ile es Staining and Remedial Measures
Storage Mortar Mortar Plasticisers and Air Entrainers J oin ints ts
Expo xposure sure .... ........ ......... ......... ......... ......... ......... ......16 .16 Exposure of Brickwork Exposure to Wind-Driven Rain Exposure within Brick Construction Water Penetration Design Detailing and Design Features Damp Proof Courses
Movement ovemen t .... ........ ......... ......... ......... ......... ......... ......24 .24 Movement of Brickwork Ancillary Fixings
Appearance Cavity Ties DPCs and Cavity Trays Protection Cavity Insulation Bricklaying in Winter
Other t her Sources of Referen eference ce .... ........32 ....32 Design an andd Technical Services.....33 Product rod uctss an andd Services..... Services......... ........ .......34 ...34 Cont act Numbe rs ..... ......... ......... ......... ........36 ....36 3
Brick Selection TEXTURES
Brick Types and Textures Th T he col colou ourr an and te textu ture re of br bric ick ks is is in infl flu uence ced d bot both h by by fi firi rin ng an and
Extruded Perforated Wirecut Bricks
shaping and by the addition of minerals and pigments, but the characteristics of the clay are crucial. Ibstock's widely distributed manufacturing plants produce an exceptional range of colours and textures from a variety of local clays. The company has extensive natural resources including vast reserves of Etruria Marl and Weald clays, as well as many other
Smooth
excellent shales and fireclays. Heavy investment in some of the most up-to-date computerised plant and equipment in Europe means that manufacturing and firing
Sandfaced
processes can be closely controlled, and automated brick handling ensures rapid distribution to all parts of the country. Ibstock bricks are manufactured to BS 3921:1985 - 'Specification for Clay Bricks’. For a technical specification please refer to
Dragfaced
Ibstock Brick ‘The Range’ or visit our website at www.ibstock.co.uk.
BRICK TYPES
Rolled / Creased
Perforated (Perforation patterns vary). Perforated bricks shall have holes not exceeding 25% of the gross volume of the brick (BS 3921:1985)
Rusticated - should be laid with texture pointing downwards
Frogged rogged,, Machine Moulded , Rep epresse resse d an andd Tra raditiona ditiona l Stock Bricks - are laid frog up
Frogged Frogged bricks shall have depressions in one or more bed surfaces but their total volume shall not exceed 20% of the gross volume of the brick (BS 3921:1985).
Sand Creased Smooth Sanded Some Stock Bricks may be rotated to create a different aesthetic appearance if preferred.
Engineering
Handmade
Th T hese are are not chos ose en for for app ppe eara ran nce, have no no re requ quir ire ement for for colour and/or texture. They have a guaranteed minimum compressive strength (Class A
!
70N/mm2, Class B ! 50N/mm2), and a
maximum water absorption (Class A
4
Repressed
"
4.5%, Class B " 7.0%).
Waterstruck - should be laid with the lip at the bottom
Brick Selection DIMENSIONAL VARIATION
SPECIAL SHAPE BRICKS
BS 3921 specifies brick size and tolerance (based on the
A comprehensive range of special shape bricks, manufactured to
measurement of 24 bricks).
BS 4729:1990, is readily available and these can be supplied to
It is important to understand that bricks complying with the standard have varying shape characteristics depending on the method of manufacture. For example, the moulded process by which some stock bricks are made results in a less uniformly shaped product than that made by the wirecut or pressed process. Th T he de desig ign ner mu must take ac acco cou unt of of th this is,, part partic icu ula larl rly y fo forr sit situ uati tion ons s
complement or contrast with any colour or texture in the Ibstock range. Non standard specials (in virtually any shape, size or finish) are also available to individual specification. Th T hey can be be use used to to re reso solv lve e bon bondi din ng pro probl ble ems at at ch changes of of angle, to enhance the appearance of window and door openings or to create decorative features such as corbels. The Ibstock
such as piers, columns and brickwork between windows where
Special Shaped Bricks literature illustrates our comprehensive
close dimensional control may be required.
range of Specials.
Bricks should be selected from several packs on site, both to minimise the possibility of variable joint dimensions and to achieve appropriate colour mixing throughout the facing brickwork, as described in Clauses 30.2 and 32.4 of BS 5628:Part 3:1985, also BS 8000:Part 3, clause 3.5.
How to Specify Special Shape Bricks Please leas e provide us wi with th the foll following: owing: 1. Prod oduc uctt type type.. 2 . Special brick type - code an andd full de scription. 3. Appli pplication cation - suitab suitab il ility ity of specials specials for exposure requirements.
DEFINITION OF SIZES
4. Qua nt ntity ity req required. uired.
Co-ordinating Size - the size of a co-ordinating space allocated to a brick, including allowances for joints and tolerances.
5. Deli Delivery very - comme commencem ncement ent an d pha sing - ma manufact nufact uring progra mme li linked nked to const ruct ruction ion progra mme mme..
Work Size - the size of a brick specified for its manufacture, to
6 . Packa Packaging ging req uireme uirements nts..
which its actual size should conform within specified
7. Orient at ion of spe cial (e.g. for wi windo ndo w ope ning, is ap plication for cil cill, l, revea l or hea d? d?))
permissible deviations.
8. Consequ onsequent ent requirements requirements for texture. texture. Sizes
9. Hand ing req uireme uirements nts - wi with th resp ect to asymm asymmet et ric sha pes Len Le ngth mm
Wid idth th mm Hei eig ght mm
Co-ordinat ing size
22 5
11 2.5
75
Work size
21 5
10 2.5
65
and n d direct ional text ure (Not (Note:e:- some han ding conven convention tion to BS 47 2 9 is opp osite to what might be expe expecte cted) d) . 10 . Speci Special al angle angle requirements.
Co-ordinating Sizes
11 . Speci Special al requirements requirements at returns. 12 . Specif Specifyy ifif solid solid bricks bricks are req uired, and a lso ifif the bed nee ds to be faced .
22 5 112.5
13 . NonNon-standa standa rd faces faces or textures.
75
14 . Posi Position tion of perforations perforations or other holes. 10 cross joint joint
15 . Speci Special al requirements requirements for tolerances. 16 . Associ ssociated ated bric bricks ks required (e.g. plinth plinth st retchers may
10 bed joint
also req uire plinth hea de rs) rs).. 17 . Posi Position tion of code sta mp. Add Add iti itional onal points for for non-sta on-s ta nd ndard ard sha pes 18 . Desc Descri ription ption of application. application. 19 . Avail vailab ab il ility ity of dra wi wings ngs of both prop osed sha pes an d the ir ap plication in work.
102.5
2 0. Is de sign input an d ad vice req uired?
21 5
2 1 . Are cut an andd bon bonde de d sha shape pess acce accept pt ab le? If so this could
65
lead to quicker ava il ilab ab il ility ity..
Work Sizes 5
Brick Selection BRICKWORK BRIC KWORK DIMENSIONS Brickwork dimensions should be used whenever possible at the design stage, to minimise the need for cut bricks. Tables 1 and 2
All brickwork dimensions are then determined by one of three conditions.
1. Brick + 2 J oints
eg: door and window openings
give dimensions for vertical and horizontal brickwork courses, based on the British Standard co-ordinating size of 225mm x 112.5mm x
2. Brick + 1 J oint
CO
Brick panel with opposite return ends
75mm, which includes 10mm joints, (this size being identified by the term CO). Table 1 & 3 should be used for 73mm bricks.
CO+
3. Brick only
CO -
Brick Piers or Panels between openings Note: In order to avoid cutting bricks, panels should therefore be either CO+, CO or CO- as indicated in Figure 1.
Council Offices, Brighton, East Sussex Roughdales Albany Cream
6
Brick Selection TABLE 1 - HORIZONTAL HORIZONTAL BRICKWORK DIMENSIONS DIMENSIONS USING 215mm BRICKS AND 10mm 10mm MO MOTAR TAR JOIN J OINTS TS Number
CO +
CO
CO -
Number
CO+
CO
CO-
of Bricks
J oi oint
(Co-ordinating Size)
J oi oint
of Bricks
J oint
(Co-ordinating Size)
J oint
1 2 2 .5
1 1 2 .5
1 0 2 .5
25
56 35
56 25
56 15
2 35
225
215
57 47 .5
57 37 .5
57 27 .5
3 4 7 .5
3 3 7 .5
3 2 7 .5
58 60
58 50
58 40
46 0
45 0
44 0
59 72 .5
59 6 2.5
59 52 .5
57 2 .5
56 2 .5
55 2 .5
60 85
6 07 5
60 65
685
6 75
665
61 97 .5
6 18 7.5
6 17 7.5
79 7.5
78 7.5
77 7.5
63 10
6 30 0
62 90
91 0
90 0
8 90
64 22 .5
6 41 2.5
6 40 2.5
1 0 2 2 .5
1 0 1 2 .5
1 0 0 2 .5
65 35
6 52 5
65 15
11 35
11 25
11 15
66 47 .5
6 63 7.5
6 62 7.5
1 2 4 7 .5
1 2 3 7 .5
1 2 2 7 .5
6760
6 750
6740
13 60
13 50
13 40
68 72 .5
6 86 2.5
6 85 2.5
1 4 7 2 .5
1 4 6 2 .5
1 4 5 2 .5
6985
6 975
6965
15 85
15 75
15 65
70 97 .5
70 8 7.5
70 77 .5
1 6 9 7 .5
1 6 8 7 .5
1 6 7 7 .5
72 10
7200
71 90
1810
18 00
1790
73 22 .5
73 1 2.5
73 02 .5
1 9 2 2 .5
1 9 1 2 .5
1 9 0 2 .5
7435
742 5
7415
20 35
20 25
20 15
75 47 .5
75 37 .5
75 2 7.5
2 1 47 .5
2 13 7.5
2 12 7.5
76 60
7650
76 40
2260
22 50
22 40
77 72 .5
77 6 2.5
77 52 .5
2 37 2 .5
2 36 2.5
2 35 2 .5
78 85
7875
78 65
2485
2475
2465
79 97 .5
79 8 7.5
79 77 .5
2 59 7.5
2 58 7.5
2 57 7.5
8110
8100
8090
8 2 2 2 .5
8 2 1 2 .5
8 2 0 2 .5
8335
8 32 5
8315
8 4 4 7 .5
8 4 3 7 .5
8 4 2 7 .5
8560
8 550
8540
8 6 7 2 .5
8 6 6 2 .5
8 6 5 2 .5
8785
8 775
8765
8 8 9 7 .5
8 8 8 7 .5
8 8 7 7 .5
90 10
90 00
89 90
91 22 .5
91 1 2.5
91 02 .5
92 35
92 2 5
92 15
93 47 .5
93 37 .5
93 2 7.5
94 60
94 50
94 40
95 72 .5
95 6 2.5
95 52 .5
96 85
96 75
96 65
97 97 .5
97 8 7.5
97 77 .5
99 10
99 00
98 90
1 0023
1 0 0 1 2 .5
10003
/
1 2
1 1 /
1 2
2 2 /
1 2
3 3 /
1 2
4 4 /
1 2
5 5 /
1 2
6 6 /
1 2
7 7 /
1 2
8 8 /
1 2
9 9 /
1 2
10 10 /
1 2
11 11 /
1 2
2 5 /
1 2
26 2 6 /
1 2
27 2 7 /
1 2
28 2 8 /
1 2
29 2 9 /
1 2
30 30 /
1 2
31 31 /
1 2
32 32 /
1 2
33 33 /
1 2
34 34 /
1 2
35 35 /
1 2
36
consider movemen t joints for copings and capp capp ings
12 12 /
1 2
13 13 /
1 2
14 14 /
1 2
15 15 /
1 2
16 16 /
1 2
17 17 /
1 2
18 18 /
1 2
19 19 /
1 2
2 0 20 1 / 2 2 1 21 1 / 2 2 2 22 1 / 2
36 1 / 2
2710
2700
26 90
2 8 22 .5
2 81 2.5
2 80 2 .5
2935
2925
2915
3 0 4 7 .5
3 0 3 7 .5
3 0 2 7 .5
31 60
31 50
31 40
3 2 7 2 .5
3 2 6 2 .5
3 2 5 2 .5
3385
3375
3365
3 4 9 7 .5
3 4 8 7 .5
3 4 7 7 .5
36 10
36 00
3590
3 7 2 2 .5
3 7 1 2 .5
3 7 0 2 .5
38 35
38 25
38 15
3 9 4 7 .5
3 9 3 7 .5
3 9 2 7 .5
4060
4050
4040
41 72 .5
41 6 2.5
41 52 .5
42 85
42 75
42 65
43 97 .5
43 8 7.5
43 77 .5
45 10
45 00
44 90
46 22 .5
46 1 2.5
46 02 .5
47 35
47 25
47 15
48 47 .5
48 37 .5
48 2 7.5
49 60
49 50
49 40
50 72 .5
50 6 2.5
50 52 .5
37 37 1 / 2 38 38 1 / 2 39 39 1 / 2 40 40 1 / 2 41 41 1 / 2 42 42 1 / 2 43 43 1 / 2 44 44 1 / 2
consider moveme nt joints at 10 - 12 m max cent res in half brick skins to cavity walls
45 45 1 / 2 46 46 1 / 2 47 47 1 / 2
consider movement joints joints at 5 - 6m max centre s in pa rap et and freest freest anding walls, alls, also where diff differing ering mat erials are used or different colour bricks
2 3 23 /
1 2
2 4 24 /
1 2
51 85
51 75
51 65
52 97 .5
52 8 7.5
52 77 .5
54 10
54 00
53 90
55 22 .5
55 1 2.5
55 02 .5
48 48 1 / 2 49 49 1 / 2 50
1 01 35
1 01 25
1 01 15
1 02 48
1 0 2 3 7 .5
10228
1 03 60
10 35 0
10 34 0
1 0473
1 0 4 6 2 .5
10453
1 05 85
10 57 5
10 56 5
1 06 98
1 0 6 8 7 .5
10678
1 08 10
10 80 0
10 79 0
1 0923
1 0 9 1 2 .5
10903
1 10 35
11 02 5
11 01 5
1 11 48
1 1 1 3 7 .5
11128
1 12 60
11 25 0
11 24 0
7
Brick Selection TABLE 2 - VERTICAL BRICKWORK COURSES DIMENSIONS TABLE USING USI NG 65mm BRIC BRICKS KS AND 10mm MORTAR JOINTS JO INTS Course
Height
Course
Height
Course
Height
TABLE 3 - VERTICAL BRICKWORK COURSES DIMENSIONS TABLE USING USI NG 73mm BRIC BRICKS KS AND 10mm MORTAR JOINTS JO INTS Course
Height
Course
Height
Course
Height
1
75
18
1 350
35
2625
1
83
18
1494
35
2905
2
15 0
19
1 42 5
36
2 70 0
2
16 6
19
15 77
36
29 88
3
225
20
1 500
37
2 775
3
249
20
1660
37
3071
4
30 0
21
1 57 5
38
2 85 0
4
33 2
21
17 43
38
34 54
5
37 5
22
1 65 0
39
2 92 5
5
41 5
22
18 26
39
32 37
6
45 0
23
1 72 5
40
30 00
6
49 8
23
19 09
40
33 20
7
52 5
24
1 80 0
41
30 75
7
58 1
24
19 92
41
34 03
8
600
25
1875
42
3150
8
664
25
2075
42
3486
9
67 5
26
1 95 0
43
32 2 5
9
74 7
26
21 58
43
35 69
10
750
27
2 02 5
44
3300
10
830
27
22 41
44
36 52
11
825
28
2100
45
3375
11
91 3
28
2324
45
3735
12
900
29
2175
46
3450
12
996
29
2407
46
38 18
13
975
30
2250
47
352 5
13
1 079
30
2490
47
3901
14
1 050
31
2 32 5
48
3600
14
1162
31
2573
48
3984
15
1125
32
2 400
49
3675
15
1245
32
26 56
49
4067
16
200
33
2 475
50
3750
16
1 32 8
33
2739
50
41 50
17
1275
34
2 550
51
3825
17
1 41 1
34
2822
51
42 33
CO+ CO+ (elevation)
4 x CO +
CO + condition
door or window opening
CO condition
4 x CO
CO (plan)
COCO(plan)
FIGURE 1 Design to Minimise Cutting
8
CO - condition
4 x CO -
Brick Selection COMPRESSIVE STRENGTH Brick strength is related to the raw materials and to the forming and firing processes used in manufacture. Bricks are available with compressive strengths ranging from 5N/mm2 to greater than 70N/mm2. In designs where brick strength is an important factor e.g. Ioadbearing masonry, it is recommended that designers check the latest performance data.
Buchanan Galleries, Glasgow Thr T hroc ock kle ley y Oa Oatm tmeal Textu ture red d & Nos Noste tell ll Ha Harewoo ood d Rus Russ set Buf Buff f
WATER ABSORPTION Th T he mason onry ry str tru uctu tura rall cod code e, BS 5628 5628:P :Pa art 1:1 1:1992, 992, re rela late tes s categories of water absorption (expressed as a percentage increase in weight), to characteristic flexural strength. Categories are:- less than 7%, 7% to 12% and greater than 12%. Many dense wirecut bricks fall into the first category while moulded stock bricks are generally in the latter.
DURABILITY
Soluble Salts Two ca cate tego gori rie es of of sol solu uble salt con conte ten nt are are de defi fin ned: Th he pe perc rce enta tage ge by mass of of sol solu ubl ble e ion ions s, me measure red d as as Low (L) T described in appendix B of BS 3921:1985 shall not exceed the following: Magnesium 0.030% Potassium 0.030% Sodium 0.030%
BS 3921:1985 classifies durability by specific reference to frost
Sulfate 0.500%
resistance and to soluble salts content. Th here is no direct relationship between water absorption and Note: T frost resistance - many bricks with a high water absorption also have excellent frost resistance.
Normal (N) Magnesium Potassium Sodium
Frost Resistance
}
the sum of 0. 0.25 25% %
Sulfate 1.6%
Th T hre ree e ca cate teg gor orie ies s of of fro fros st re resis ista tan nce are are de defi fin ned:
1. Frost Resis Resistant tant (F) Bri Brick ckss - durable in all building situations including those where they are in a saturated condition and subjected to repeated freezing and thawing. Examples where brickwork is likely to become saturated include below ground
Durability Designations Categories of frost resistance and soluble salt content are combined in BS 3921:1985 to provide durability designations. (Shown in Table 4).
level dpc, parapets, copings, freestanding and retaining walls.
2 . Moder Moderat at ely Frost Resist esistant ant (M) Bri Bricks cks - durable except when in a saturated condition and subjected to repeated freezing and thawing. Generally this means that they can be used in normal walling situations between ground dpc level up to eaves (but
TABLE 4 - Durability Designations Designation
Frost Resistance
Soluble Salts Content
FL
Frost Resist an t (F)
Low (L)
FN
Frost Resist an t (F)
Norma l (N)
ML
Mode rat ely Fr Frost ost Resistan t (M)
Low (L)
Mode rat ely Fr Frost ost Resistan t (M)
Norma l (N)
OL
Not Frost Resistan t (O)
Low (L)
ON
Not Frost Resistan t (O)
Norma l (N)
not in projecting detailing).
3. Not Frost Frost Resi Resistant stant (O) Bric Bricks ks - not frost resistant. May only be used internally. Protection from the weather must be provided when stored on site and during construction.
MN
Note: Guidance on the selection of bricks and mortars for use in a variety of environments, particularly where brickwork might be subject to saturation and liable to freezing and thawing, is given in BS 5628:Part 3 - Table 13. Some of these situations are reproduced in Tables 5, 6, 7 and 8 of this publication.
9
Brick Selection
TABLE 5 - BRICKS FOR WORK BELOW OR WITHIN 150mm ABOVE GROUND LEVEL Suitable qualities
Suitable mortar
Brickwork near external ground level:
of bricks
designations
Low risk of sa tura tion - well well drained site
FL, FN1
(i) (ii) (iii)2
High igh risk of sa tura tion - poorly drained site without freezing
FL, FN1
(i) (ii)
High igh risk of sa tura tion, - poorly drained site with with freezing
FL, FN1
(i) (ii)
Brickwork rickwork wholl whollyy be low
FL, FN1, ML, MN1
(i) (ii) (iii)
ground level
3
Note s: 1. T Th he use use of su sulf lfa ate resi sist stin ing g Por Portl tla and ce cement is re rec commende ded. d. 2. Strict supervision of batching is particularly important to ensure that the requisite amount of cement is incorporated in designation (iii) mortars. 3. Where brickwork is (at least 150mm) below finished external ground level, most ML and MN clay bricks can be suitable, although the manufacturers’ recommendations should be sought.
TABLE 6 - BRICKS FOR EXTERNAL WALLS OF BUILDINGS (excluding parapet walls, chimney stacks, cills, copings and cappings).
Low risk of sat ura tion. Walling well prot ect ed by roof overha ngs, cil cills ls an d cladd ing de signed to she d wate r clear of brickwork. High igh risk of sa tur at ion. Bric Brickwork kwork inad eq uat ely prot ect ed an d sa tura te d by wate r run-off
Suitable qualities
Suitable mortar
of bricks
designations
FL, FN1, ML, MN1
(i) (ii) (iii)
FL
(i) (ii)
FN
1
(i) (ii)
Note : 1. T The he use of sul ulfa fate te-re -resi sist stin ing g Por Portl tla and cement is re rec commende ded d wit ith h de desi sign gna ati tion on (ii (ii)) or (ii (iii) i) mor orta tarr.
TABLE 7 - BRICKS FOR BOUNDARY WALLS OR PARAPETS (excluding the coping or capping). Suitable qualities of bricks
Suitable mortar designations
Effective ffective coping use d
FL, FN1, ML, MN1
(i) (ii) (iii)
Flush lush cap ping use d
FL
(j) (ii)
FN1
(i) (ii)
Note : 1. T The he use of sul ulfa fate te-re -resi sist stin ing g Por Portl tla and cement is re rec commende ded d wit ith h de desi sign gna ati tion on (ii (ii)) mor morta tarr.
TABLE 8 - CILLS, CHIMNEYS, COPINGS AND CAPPINGS
Sta nda rd format bricks an d Sta nda rd 3 or purp ose-m ad e spe cial sha pe s
Suitable qualities
Suitable mortar
of bricks
designations1
FL, FN2
Note s: 1. Designation (i) mortar should be used for bedding associated DPCs in clay brickwork. 2. When used in chimney cappings, sulfate-resisting Portland cement is recommended. BS 4729 4729.. 3. To BS
10
(i)2
Brickwork MORTARS Selection of the correct mortar mix depends on:
Adhesion To ac achie iev ve goo good d adh adhesio ion n a mor orta tarr mu must ha have goo good d wor orka kab bil ilit ity y.
1. Bri Brick ck cha chara racte cteris ristic tics. s.
Mortar of poor workability will not perform adequately, and will
2. De Degr gree ee of exp expos osur ure. e.
allow air to be trapped between the mortar and the brick, thus
3. Applic Application ation within the con constru struction ction..
preventing good bond formation. Bricks with rough bed faces
4. Se Season ason when bricklay bricklaying ing takes takes place place..
and medium suction rates will have high bond characteristics because the mortar will key into the texture of the brick.
Lime
Conversely, bricks with low suction rates and a smooth texture
Hydrated lime is manufactured to BS 890:1995 as a dry powder.
will have lower bond characteristics.
Th T his gr gre eatl tly y impr prov oves th the su subs bse equ que ent wor orka kab bil ilit ity y and lon long g te term
Highly porous bricks may rapidly absorb moisture during laying
performance of the mortar. It is recommended that ready mixed
(particularly in warm weather), causing the mortar to become
lime:sand for mortar is used conforming to BS 4721:1986 when
insufficiently plastic to allow repositioning of the bricks during
tested by the methods given in BS 4551:1998. (Partially replaced
levelling. It is possible in such circumstances that no adhesion will
by BSEN 1015).
be obtained between bricks and mortar. Laying mortar beds in
Sand Well graded soft sand is recommended for brickwork mortar,
shorter lengths to reduce drying will help. Wetting may assist adhesion, but over wetting may lead to floating on the mortar bed and to excessive efflorescence and staining.
meeting the requirements of BS 1200:1996.
Workability Cement
Mortars containing only sand and cement tend to be coarse and
Only use cement conforming to BS 12. Specification for
hard to work, often requiring more water than may be desirable for
Portland cement.
strength considerations. The addition of lime increases workability,
On Site Mixing
reduces the water requirement and slightly increases strength.
A recognised method of gauging is recommended to ensure that
Admixtures
the correct designation of mortar is achieved.
Bonding agents, waterproofing admixtures and air entrained
Ready to Use Mortar It is recommended that the mortar suppliers' recommendations are
mixtures can all be added to mortars. However, their use must be strictly controlled and in accordance with the manufacturers’ instructions, particularly to avoid over mixing.
strictly followed when using ready to use (retarded) mortar.
Permeability Quantity Yield One tonne of ready mixed lime:sand, when gauged with the specified quantity of cement on-site, will generally be sufficient to lay approximately 1000 bricks.
Coloured Mortars A wide range of light-fast colours and shades is available and these are supplied by leading manufacturers. Ibstock Brick’s Technical Services can give advice on toning mortars to suit most products in the Ibstock Brick range.
Strong mortars will provide better resistance to water penetration, but offer less resistance to differential movement. Rain penetration can be greatly reduced by good design and proper selection of the sand grading. Rich mortars (high cement content) will crack more easily than weak mortars. Weak mortars are more tolerant to movement but the voids between the sand grains will, however, contain less cement, allowing water to penetrate more easily. Uneven mixing of the mortar can result in a cement deficiency in some areas, and rain penetration can occur under some conditions of moderate exposure.
11
Brickwork MORTAR PERFORMANCE Th T he air air sp spa ace wit ith hin sand re repr pre esents app ppro rox xim ima ate tely ly on one e th thir ird d of of th the
Private House, Scunthorpe, Lincolnshire Ashdown Village Mixture
volume. The strength and physical properties of mortar are altered by the types of binder used to fill that air space. For example, 3 parts sand to 1 part cement will result in the sand voids (air spaces) being completely filled, producing a very strong but brittle mortar. Alternatively 3 parts sand to 1/2 part cement to 1/2 part lime produces a well filled mortar, but with the extra adhesion and flexibility given by the lime, balanced by the strength of the cement. Th T his is a 1:1: 1:1:6 6 mix mix.. Altering these proportions to suit the strength requirement, exposure level, workability or weather conditions can be of
Only with high suction rate bricks in warm weather conditions
considerable benefit to the durability of the final brickwork. (As
should docking (or wetting) of the bricks be considered. If it is
shown in Table 9).
undertaken the bricks should not be soaked and only clean fresh water should be used to avoid soluble salt contamination. A method
Variations in the water suction rate of bricks can adversely affect
for testing the suction rate is laid down in BS 3921 Appendix H.
bricklaying. The wetness of the mortar mix can be increased or
In the case of loadbearing brickwork, a test in accordance with
reduced to maintain a consistent level of moisture whilst laying.
BS 5628:Part 1, can be specified to discover whether docking is necessary or advisable. TABLE 9 - MORTAR MIXES FOR BRICKWORK
Morta r de signat ion
Increasing strength1 an d improving dura bili bility ty
Increas ing ab il ility ity to accom mod at e moveme nts due to te mpe rat ure an d moistu re chan ge
Type of mort ar 2
Cement :lime:sa nd 3
Air-entra ined mixes 5
Propor tions by volume 4
Maso nry ceme nt: sand 3 Propor tions by volume
Cement :sa nd wi with th plast ici iciser ser 3 Propor tions by volume
(i)
1 : 0 to 1/4 : 3
(ii)
1 : 1/2 : 4 to 41/2
1 : 21/2 to 31/2
1 : 3 to 4
(iii)
1 : 1 : 5 to 6
1 : 4 to 5
1 : 5 to 6
(iv)
1 : 2 : 8 to 9
1 : 51/2 to 61/2
1 : 7 to 8
(v)
1 : 3 : 10 to 12
1 : 6 / to 7
1:8
1 2
Increas ing resist an ce to frost at ta ck dur ing const ruction Improveme nt in ad hesion an d resist an ce to rain pe net rat ion
Note s: 1 . Where mortar of a given compressive strength is required by the designer,
Th he ra range of sand con conte tent nts s is is to to all allow ow fo forr the eff ffe ects of th the e dif diffe fere renc nces in in 3. T
the mix proportions should be determined from tests following the
grading upon the properties of the mortar In general the lower proportion of
recommendations of appendix A of BS 5628:Part 1:1992.
sand applies to grade C of BS 1200 whilst the higher proportion applies to
Th he dif diffe fere rent ty type pes of of mor orta tarr tha that com compr pris ise e any on one e de desi sign gna ati tion on are 2 . T
grade S of BS 1200.
approximately equivalent in compressive strength and do not generally differ
Th he pro propo port rtio ion ns are are ba base sed on on dry dry hydr dra ate ted d lim lime. The The pr prop opor orti tion on of li lim me by by 4. T
greatly in their other properties. Some general differences between types of
volume may be increased by up to 50% (V/V) in order to obtain workability.
mortar are indicated by the arrows at the bottom of the table, but these
5. At the discretion of the designer, air entraining admixtures may be added
differences can be reduced (see 23.2. BS 5628:Part 3:1985)
to lime:sand mixes to improve their early frost resistance. (Ready mixed lime: sand mixes may contain such admixtures).
12
Brickwork BRICK BONDING
Flemish Garden Wall Bond
Th T he cre crea ati tiv ve us use of of bri brick ck bo bon ndi din ng, wit with h or or wit ith hou outt con contr tra asti tin ng or or
Like English Garden Wall bond, this was originally intended
complementary brick colours, can have a dramatic effect on the
for use in solid walls which were required to be
appearance of a building.
fair faced both sides. Th T he nu number of of
In recent times stretcher bond has predominated, mainly because of
stretchers is increased
the speed with which it can be laid in cavity wall construction. There
and three stretchers
are, however, other traditional methods which can be used to enrich
are laid to one header
large areas of brickwork, although extra cutting is needed.
in each course.
English Bond Alternative courses of headers and stretchers; one
Stretcher Bond
header placed centrally above each stretcher. This is a very strong bond
Originally used for single
when the wall is
brick walls, now called 1/2
1 brick thick (or
brick walls it became
the obvious choice for
thicker).
cavity walls as less cutting was required.
Raking Bonds Herringbone and diagonal bonds can be effective
Flemish Bond
within an exposed framed construction, or Alternate bricks are placed as header and stretcher in
contained within
every course. Each header is placed centrally
restraining
between the stretcher
brick courses.
immediately above and below. This is not as strong as the English bond at 1 brick thick.
Quantities One square metre of brickwork, a half brick thick, requires the following number of bricks:
English Garden Wall Bond
English Eng lish bon bond d ... ...... ...... ...... ..... ..... ..... ...86 .86
Flemish Ga Garde rden n Wa Wall ll bon bond.. d....6 ..67 7
An alternative version of English bond with header
Flem Fle mish bo bond nd .... ........ ........ ........ ......77 ..77
Stre tretch tcher er bond .... ........ ........ ........ ........ ....60 60
courses being inserted at
English Garden Wall bond..72
every fourth or sixth course. This is a correspondingly weaker bond.
Figures are assuming one header per brick. English and Flemish bonds are attractive for dwarf and retaining walls where only one good face is required. Stretcher bond is the most economical of all. To cre crea ate a wall whic ich h is is fa fair ir-fa -face ced d on on bot both h sid side es, two str stre etc tch her wa wall lls s are built side by side with a continuous mortar joint between them, the two walls being bonded together with ties (these are also called collar jointed walls). Snap headers are a simple way of adding variety.
13
Brickwork J OI OINT NT PROF OFIL ILE ES Th T he eff effic icie ien nt sh shedd ddin ing g of of wate terr by by mor orta tarr joi join nts is essenti tia al for for lo lon ng term performance. Masonry that remains saturated is more susceptible to frost and sulfate attack. The choice of joint profile should therefore be based first on performance criteria, with aesthetic considerations being secondary. Tooling of the joints to compact the mortar improves durability and rain-shedding qualities.
Quality of Workmanship Th T he qu quali lity ty of wor ork kmanship on sit ite e ca can ha have an an ov overr rrid idin ing g eff effe ect on the weather resistance of the brickwork. 1. Bricks shou should ld be laid on a full full bed of mortar mortar. 2. All cross joints and and collar joints joints should should be fully filled. 3. Immediate ediately ly after after the brick is laid, exces excess s mortar mortar should should be struck off the external face of the work and off the internal faces of the leaves of cavity walls. 4. Care shou should ld be taken taken to ensu ensure re that that mortar mortar is not scraped scraped onto onto the exposed face of the brick. 5. Unles Unless s otherwise otherwise spec specified, ified, frogged bricks should should be laid frog up and the frogs should be filled with mortar completely.
Curved Recessed (Bucket Handle) Th T his jo join intt giv give es an an im impr prov oved app appe eara ran nce over a fl flu ush joi join nt, wit ith h lit littl tle e
Struck or Weathered (Weatherstruck) Th T his pr prod odu uces a co con ntr tra asti tin ng eff effe ect of of lig ligh ht an and sh shade on th the e
reduction in strength. Owing to the compressing of the joint and
brickwork. Such joints, when correctly formed, have excellent
the superior bond, it has good weather resistance, and is suitable
strength and weather resistance and are suitable for all grades
for all grades of exposure.
of exposure.
Flush
Square Recessed (Raked)
Th T his gi giv ves maximum be bea ari rin ng are area a an and is is oft ofte en fa favou oure red d when coarse textured bricks are used. With some brick types the finish may appear a little irregular. Suitable for moderate and sheltered exposure exposures. s.
Th T his ca can n pro produ duc ce in inte tere res sti tin ng art artic icu ula late ted d joi join nts ts,, but but weath the er resistance and strength will be considerably less than with other join jo ints ts.. Use Use on only wit ith h fro fros st re resis ista tan nt bri bric cks in shelt lte ere red d ex expo pos sure conditions. The recess should not exceed 3-4mm and is not recommended with full fill cavity insulation.
14
Brickwork STAINING AND REMEDIAL MEASURES
Cement Staining
First of all it is important to identify the type of stain or deposit on
Remove large deposits with a wooden tool to prevent damage to
the brickwork. Secondly, of equal importance, is the need to
the brick face. The residue should be treated with a 10%
observe all necessary health and safety regulations with the use of
hydrochloric acid solution for darker bricks and a 5% solution for
acids. Generally, efflorescence is soluble in water, stains are not.
lighter bricks. Pre-wet the brickwork prior to the use of acids. Final rinse should be with a very low pressure washing. DO NOT
White Efflorescence As brickwork dries out some water soluble salts present in the overall construction may form as a white deposit upon the surface. Efflorescence can be unsightly but it is not harmful and will
SATURATE THE BRICKWORK.
Lime Running (Leaching) Th T his is simil ila ar to to whit ite e eff efflo lore res scence but is hard not po pow wdery. It is is
ultimately disappear over a period of time by the natural action of
caused when an excess of rainwater combines with fresh, uncured
the wind and rain.
mortar to release free limes present in the cement to form calcium
Th T he ris risk k of of eff efflo lore res sce cen nce ca can n be be re redu duc ced by by th the e cor corre rect ct pr prot ote ect ctio ion n of bricks and brickwork to avoid saturation. Chemicals should not be used for the removal of white efflorescence. It should be cleaned off using only a bristle brush followed by a damp sponge if necessary. The deposit should be collected and removed from site so that it does not enter the brickwork elsew elsewhere. here.
carbonate deposits on the surface of the brickwork. Removal of this type of stain should be carried out at the earliest opportunity as delay will result in carbonation which is difficult to remove. To re remov ove e, we wet the bri bric ckwor ork k wit ith h cle clea an ta tap wate terr to to reduce suction. DO NOT SATURATE THE BRICKWORK. Brush on a 10% solution of hydrochloric acid. The brickwork should
If efflorescence persists it is likely that a design fault or poor
then be thoroughly scrubbed to remove the staining, then washed
workmanship is allowing excessive amounts of water to soak into
off with clean water. It may be necessary to repeat the cleaning
the brickwork.
process more than once depending on severity.
Yell llo ow or Gr Green Efflo lore res scence
Crazing
Th T hese eff efflo lore resc sce ences or or sta stain ins s are are common only ly assoc ocia iate ted d wit ith h ne new
Crazing to the face of bricks will generally only affect very dense
brickwork in buff or cream coloured bricks and are due to the
wirecut products, for example, Smooth Blue. No specific time period
presence of vanadium salts commonly found in the fire clays used in
can be given as to when, or indeed if, this will occur.
the making of these bricks.
Crazing is exaggerated in work by the deposit of impurities from
Like white efflorescence they should be allowed to weather away
mortar and rain. Once the brickwork is cleaned down and the
naturally. Chemical washing with a proprietary brick cleaner is likely
impurities washed away, the evidence of the crazing is minimised.
to create a dark stain.
Staining of Blue Bricks If this efflorescence is so pronounced as to require chemical cleaning, it is recommended that a trial be carried out to a small unobtrusive area of brickwork using a dilute solution of oxalic acid, directly onto dry brickwork. This is followed by the application of washing soda, which is left on the wall.
Staining of blue bricks is commonly called "Peacocking". It appears as an oil coloured type of stain on the face of the bricks and is a natural characteristic of these products. Th T he mos ostt com common sta tain in to bl blu ue bri brick cks s whic ich h is is sim simil ila ar in in appearance to "Peacocking" is associated with the saturation of
Iron Staining
bricks and brickwork prior to and during construction which leads
Normally light to dark brown in colour it is generally most
to calcium deposits drying on the face of the bricks. Good site
pronounced on the mortar joints. This type of stain can be avoided
protection to unused bricks and uncompleted brickwork is essential
by good site protection to unfinished and "green" brickwork. It is
to minimise, and in many cases, prevent this stain occuring.
best left to weather away, but the mortar joint colour can be restored by abrading with a round file.
15
Exposure EXPOSURE OF BRICKWORK A major factor influencing the performance of brickwork is the
Th T he expos osu ure of th the e sit site e an and of of dif diffe fere ren nt pa part rts s of of th the bu buil ild din ing g wil illl
degree to which it becomes saturated. Good design aims to
have a bearing on the choice of both brick and mortar mix. The
minimise water ingress, as excessive saturation can lead to frost or
degree of exposure of the site is classified either in terms of the
sulfate attack and staining or corrosion of non-stainless steel wall
local spell indices, calculated using BS 8104:1992 or in terms of
ties or reinforcement. Use of the appropriate DPC materials in the
the exposure categories given in BS 5628:Part 3:1985, BRE
correct positions will also significantly reduce saturation.
Report Thermal Insulation - Avoiding Risks or NHBC Standards.
TABLE 10 - FACTORS AFFECTING RAIN PENETRATION OF CAVITY WALLS
Fact or affecting rain pe net rat ion
Increas ing prob ab il ility ity of ra in pen et rat ion in the direct ion of the arro w
Applied exte rna l fi finish nish
Cladding
Rendering
Morta r compo sition
Cement: t:li lim me:sand
Cement: t:s sand plu plus pla las sti tic ciz ize er
Morta r joi joint nt fini finish sh and profil profilee
Bucket handle, weathered Flush
Air spa ce (clea r cavity)
Over 50mm
50mm
Insulation
None
Partial filling with 50m 50 mm air space
Oth Ot her (e.g. masonry paint, water repellent)
Recessed, tooled
Recessed, untooled None
Filled with type A insula lan nt (50 (50m mm cavit ity y)
Filled with type B insula lan nt (50 (50m mm cavit ity y)
Note : The T he ta tabl ble e doe does not not ta tak ke in into accou ount nt th the e qu qua ali lity ty of wor orkm kmansh ship ip or th the e arc rchi hite tect ctur ura al de deta tail ilin ing. g. A. Type A insu insula lant nts, s, suc such as min ine era rall fib fibre re (s (se ee BS BS 6232 6232)) or or pol poly yst sty yre ren ne be beads ds,, shou should ld not be su subj bje ecte ted d to to expo posu sure re con ondi diti tion ons s mor ore e se severe th tha an th thos ose e recommended for the equivalent unfilled wall. B. Type B ins insul ula ant nts, s, suc such as ure urea a fo form rmald lde ehyde fo foa am (s (se ee BS BS 5618 5618)) and and gr gra anu nula larr pla plast stic ic fi fill lls, s, are su subj bje ect to vari riou ous s add ddit itio iona nal re rest stri ric cti tion ons s re rela late ted d to to the the local exposure conditions and the type of construction.
Torquay Police Station, Devon Swanage Handmade Torquay Blend
16
Exposure EXPOSURE TO WIND-DRIVEN RAIN
TABLE 11 - EXPOSURE TO WIND-DRIVEN RAIN
Expos xposure ure Cat egor egoryy
• Inverness
Local spe ll index calculated calculat ed as de described scribed in BS BS81 81 04 :1 99 2
Aberdeen •
L/m L/ m2 per spell
Severe
More th than an 10 0
Moderat oder at e / Severe
56 .5 to 10 0
Moderat oder at e
33 to 56 .5
Sheltered heltere d
Less th than an 3 3
Dundee • Perth •
• Glasgow
• Edinburgh
• Londonderry • Carlisle
Newcastle •
Belfast • Middlesborough •
• Dungannon Enniskillen •
• York
• Hull
• Manchester
• Nottingham • Stafford
Norwich •
• Shrewsbury • Le Leicester
• Pe Peterborough
• Birmingham
• Northampton
Colchester •
Swansea • Cardiff •
London
• Bristol
• Dover •
Southampton •
Brighton •
Exeter •
17
Exposure EXPOSURE WITHIN BRICK CONSTRUCTION
flush eaves par ape t
Severe Moderat oder at e/Severe Moderat oder at e
ba lcony
Sheltere d
free sta nding interna l wall (exposure-nil)
inspection chambe r
overha nging eave s
reta ining wall
pa ving
Th T he expo pos sure cate tego gory ry of ta tall ll bu buil ildi din ngs an and th thos ose e loc loca ate ted d on on hig high h
Th T he se sele lec cti tion on of bri ric ck an and mor orta tarr for for on one e pa part of of th the bu buil ildi din ng may
ground should be classified one grade more severe than would
determine the choice for the whole structure in order to achieve
appear to be required. Certain parts of buildings may also require a
uniformity of appearance and performance.
more severe grading e.g. parapet walls, tops of walls unprotected by roof overhangs, freestanding walls and areas of walls below DPC adjacent to ground level.
18
Exposure WATER PENETRATION Some water will inevitably penetrate the outer leaf in long periods of
Penetration of a leaf built from low absorption bricks will generally
wind-driven rain. The degree of penetration depends largely on the
occur more quickly than through one built from high absorption
intensity and duration of wind and rain.
bricks in the same exposure conditions. The latter delays penetration but it will occur eventually if the rain continues long
During light wind-driven rain, damp patches usually appear first at
enough for the bricks to become saturated.
the joints on the cavity face. When the rain stops they dry out. After longer or more intense periods of wind-driven rain, the entire face may become wet and eventually water may run freely down the inner face.
Resistance of Outer Leaf to Wind-driven Rain
Slight light da mpnes s at perp ends
Cavity avity tra y virtually dry
Most of inner face da mp, but no running water
Wat er running freely down inner face
Cavity avity tra y da mp
Sheltered
Moderate
Severe
Stand ing water in cavity tra y (dra ins from weepholes when wi wind nd drop s)
Potential Routes for Water Penetration
Open perp end Wate r directed into insulation
Morta r obst ruction Tie sloping down to inside leaf
Wat er splashe s off extrud ed bed
Tie sheds water into cavity
Dispa ispa ced boa rd catche s drips
Slabs overlapp ed water directed in
Wate r now on inner leaf
Cavity avity bridged ab ove DPC
Unfilled Cavity
Ponding
Partially Filled Cavity
Filled Cavity 19
Exposure DESIGN DETAILING Good design involves the durability of a building in addition to place, purpose, form and function. It is therefore important to design the individual elements of a building with an eye to the prevention of future defects. For sites of severe exposure special details may be necessary, but in many other cases simply following established good practice guidelines will help to minimise future problems. Essentially the main factor to take into account in the UK climate is water penetration from above and below. In addition to the aspects previously indicated, other factors, such as structural stability and lack of movement joint provision, may also have a bearing on the weather resistance capabilities of brickwork, e.g., moisture penetration through cracks.
Overha nging eave s to increase prot ection to wall below
Where architectural details which increase exposure are considered essential to the design, it is necessary to ensure that the bricks specified are of the appropriate durability designation. Insulation stop ped just short of cavity tra y
DESIGN FEATURES Certain design features will increase the vulnerability of brickwork and the risk of it becoming saturated, with
Stop ends
consequent risk of frost damage. In these cases more durable
Cavity avity tra y incl including uding stop ends
bricks and mortar mixes are required, this choice may then have to be applied to the whole building.
Examples of features which will increase the local exposure are:
Drainage weephole at not great er tha n 1 metr e interva ls, minimum 2 per open ing Sealant
Recess ecessed ed wi windo ndows ws wi with th sloping mas masonry onry at the bot tom tom.. Flush lush cil cills. ls. Little or no overha ng at verges.
Timber wi window ndow frame secured t o brickwork brickwork by non corroding cramp s
Large expa nses of glazing or imper vious cladd ing ab ove masonry as onry (without provision for shed ding run-off wate water). r). Area reass of rende ring ad joi joining ning brickw brickwork ork and recesse d from it with no eff effective ective sea l or oth other er prot ection at the junction. Vert ical tile ha hanging nging wi with th li litt tt le or no project ion
IC 1.1 cill ill brick
ab ove brickw brickwork. ork. Parape ara pett or oth other er wall wallss wi with th a fl flush ush cap ping e.g. of brick.
Stop end
DPC below cil cilll ste ppe d down across cavity cavity.. Weep holes, minimum 2 per opening.
Fea tu tures res whi which ch project from the main plan planee of the wall with ithout out weat weathering hering or fl flash ashings. ings. Reference should be mad e to BS 56 28 Part s 1 an andd 3 for general ene ral inf informa orma tion on th thee de design sign of mas masonr onryy.
20
Eave/Window Section
Exposure Vertical DPC to project 25 mm into cavity and be retur ned into brickwork rickwork reba te
DAMP PROOF COURSES
Vertical DPC to project 25 mm into cavity and be retu rned into frame reba te
Sealant
Sealant , critical in this constru ction
Sub-cill, ub-cill, to project 50 mm from face of wall
Window with Rebated J am ambs bs
Vertical DPC to be lappe d in front of cil cilll DPC
Window Opening with Flush Flush Jambs J ambs
Cavity avity tra y rigidity igidity supp orte d accross cavity
Cill ill DPC bed ded in morta r
DPC
DPC
Caplock Half Round Coping
Bitume itume n polymer DPC Cavity avity closer
Rising Damp Prevention 150mm min DPC rises 150 mm min. min. across cavity
Horizontal Damp Prevention
DPC (project s a minimum of 25 mm into cavity)
Parapet Wall 21
Exposure DAMP PROOF COURSES
Gable Abutments to Cavity Walls
Stepped Cavity Tray Note : It is essential to provide a series of stepped cavity trays at each bed course which follows the profile of the roof. These are readily available from most DPC specialist providers.
22
Exposure On stee p pitched roofs it wi will ll be necess ar y to install a second tra y at high level 6
DAMP PROOF COURSES - CHIMNEYS
Detail around flue lue liner
Flue lue li liner ner
2
Fitit the front apr on 3 The top edge of the apro n fi fits ts unde r the DPC tra y. Fol Foldd down the DPC tra y projection. Fi Fitt the back gutte r sole plate 4
1
4
Build uild brickwork 1 to DPC level and add roof level DPC tra y 2
3
6
5
6 Fitit the side flashings 5 Fitit the ba ck gutte r 6
Caplock Overhan ging Coping
Horizonta orizonta l DPC
Exclusion of Water Good detailing contributes significantly in reducing the risk of water penetration. Wetting can be reduced by ensuring that water is thrown clear of the wall by the use of adequate overhangs and drips, and by providing drainage to take water away from the masonry. Large areas of glazing can produce copious amounts of surface run-off, which can cause excessive wetting and the
Thickness of wall to be relate d to height of
Mechanical prote ction to DPM Vert ical DPM to preven t staining/ efforescence on expose d face
Minimum inimum of 2 courses of DPC 1 or 2 bricks in designat ion (i)
possibility of water penetrating the masonry below. With ‘N’ durability designation bricks, where walls are likely to remain wet for long periods, consideration should be given to the use of stronger mortar mixes or sulfate resisting cement.
Retaining Wall 23
Movement MOVEMENT OF BRICKWORK Movement of brickwork should be considered at the design stage. Th T he main sou ourc rce es of of mov movement re refe fere ren nced he here re rela late te to moi ois stu ture re and temperature. Other factors may relate to loading and creep,
allowance of typically 30% to allow for the compressibility of the filler and the performance of appropriate sealants. Thus movement join jo ints ts at 10m 10m ce cen ntr tre es wil illl ne need to to be be app appro roximate tely ly 13mm wid ide e
and in certain situations, it may be necessary to consider the effects
and the distance between movement joints should ideally never
of chemical action, ground movement and settlement.
exceed 12m. Most constructions are set to a 5/6 metre grid therefore for design purposes it is normally accepted that
In general, reversible movements are caused by temperature changes and these can be calculated by reference to the
movement joints should be considered at 10/12 metre centres. Movement takes place around corners and not just in straight runs
coefficient of thermal expansion, as indicated in Appendix A4 of BS 5628:Part 3 and the Ibstock Brick Design Guide on Movement.
of masonry. It is therefore important to include all continuous masonry in the assessment.
However, irreversible expansion caused by adsorption of water molecules by the fired clay brick can be larger and continue, albeit at a reducing rate, for a period of years.
Unrestrained or lightly restrained walls (such as parapets and small freestanding walls) should be given double this amount of movement provision. In these cases, the distance between movement joints should be 5-6 metre centres, with coping and cappings at half these distances. As indicated in BS 5628:Part 3, present evidence suggests that vertical movement of unrestrained walls is of the same order as horizontal movement. This standard also refers to the use of flexible cellular polyethylene or foam rubbers as suitable compressible materials and the use of sealants such as low modulas silicone which are suitable for sealing of movement joints. This standard also advises on unsuitable materials, e.g. fibreboard. Further guidance on the selection of sealants is given in BS 6213.
Church, Bridlington, Yorkshire Roughdales Chester Red Blend
Clay and concrete units have different movement characteristics, these differences being in both magnitude and direction. They
Th T he movement pro prop pert rtie ies s of of com common bu buil ildi din ng mate teri ria als in inc clu ludi din ng brickwork are set out in Table 12.
should not be bonded together but separated by either a vertical or horizontal movement joint or by a slip plane.
Th T he spa spaci cin ng an and th thic ick kness of of mov move ement join joints ts is re rela late ted d to to th the
When brickwork is to be used to clad a reinforced concrete
detailed design, length and height of the brickwork, together with
frame, the design should make particular allowance for
any requirements for structural restraint.
differential movement.
An indication for normal storey height walls is that the joint width
Detailed advice based on BS 5628:Part 3 is available from Ibstock
(in mm) should be at least equal to the joint spacing (in m) plus an
Brick’s Technical Services Department.
TABLE 12 - MOISTURE MOVEMENT & THERMAL PROPERTIES OF COMMON BUILDING MATERIALS Reversible moisture movement %
Timber
Irreversible moisture movement%
± (0.5 - 2.5)†
4 - 70†
Stee l (d ep end ing on type ) Concrete
Coefficient of of th thermal expansion per °C X 10-6
10 - 18 (depending on type) ± (0 ( 0.02 - 0.10)
(0.03 - 0.08)
7 - 14 (depending on type)
Dense concret e aggrega te concret e prod ucts
± (0.02 - 0.04)
- (0.02 - 0.06)
6 - 12
Lightweight aggrega te concret e (a utocla ved ) prod ucts
± (0.03 - 0.06)
8 - 12
Aera te d (a utocla ved) product s
± (0.02 - 0.03)
- (0.05 - 0.09)
8
Calcium alcium sili silicat cat e bricks
± (0.01 - 0.05)
- (0.01 - 0.04)
8 - 14
Clay lay bricks
± (0.02)
+ (0.02 - 0.07)
5-8
BRICK & BLOCK
Note: +expansion -shrinkage †depending on direction measured
24
Movement ANCILLARY FIXINGS Reinforcement Brickwork is strongest in compression. The forces set up by reversible movement, irreversible movement or simply by changes in section due to door or window openings, can induce tensile forces, resulting in cracking. Such behaviour may be modified or controlled by bed joint reinforcement which can accommodate the tensile forces and help bond adjacent courses together in a homogeneous mass. Stitching rods may be inserted and grouted into the perforations contained in some bricks to both locate and support the bricks over door and window openings. The rods should be stainless steel and used in accordance with the Structural Engineer's specification.
Mechanical Fixings Innovative brickwork detailing, particularly corbelling that exceeds the recommendations of BS 5628:Part 3, or where the bearing for
Ikon Gallery, Birmingham, West Midlands
Leicest er Red Stock
successive courses in 103mm brickwork is less than 70mm, may require proprietary channels, cranked or special shape ties and angle supports fixed back to a reinforced concrete or concrete cased steel structure. The use of an SBR (Styrene Butadiene Rubber) additive may also be considered where bricks are to be bedded on stainless steel angles.
Wall Ties Cavity brickwork must incorporate wall ties (usually stainless steel) embedded in the horizontal mortar joints to a minimum depth of 50mm. Tie length and type (refer to BS 5628:Part 3 Table 9B) depends upon the cavity width and requirements for strength,
Non-loadbearing arches, particularly those possessing a small rise
flexibility and retention of insulation materials. Ties should
in relation to their span, may similarly require additional support
be staggered and evenly distributed in accordance with
or restraint.
BS 5628:Part 3 (Table 9A), typically at 900mm centres horizontally and 450mm centres vertically. Additional ties should also be provided within 225mm of movement joints or openings at a maximum 300mm vertical centres. Continuous runs of brickwork rickwork in buildings require movement joints joints at 10 - 12 m centres centres
Easily compres sed fil filler ler
Movement joint required where retur n is less tha n 1m
At retur ns and change in height
At junction of rest rained and unrest rained wall wallss
Positioning Position ing of Mov M ovem ement ent J oints
Unrestrained walls: alls: movemen t joints at max. 5 - 6m centre s
Outer face
Sealant
Filled and and Sealed J oints These are genera l guidelines only only.. For specific ad vice conta ct the Ibstock Bri Brick ck Design Advisory Service.
25
Insulation SOUND INSULATION Th T he sou soun nd re resis ista tan nce of a sol solid id mason onry ry wall is re rela late ted d pri prin ncip ipa all lly y to its weight (expressed as mass per unit area). For cavity walls, sound insulation is additionally related to the width of the cavity insulation and the rigidity and spacing of wall ties.
Th T he min inim imum weig igh ht of of bri bric ck to to be be us used, de depe pen ndi din ng on on th the type of construction, is indicated in Table 13. It must be remembered that the smallest crack which provides an air passage will greatly reduce sound insulation.
Part E of the Building Regulations requires the weight of a solid masonry wall (including the plaster) to be at least 375kg/m2. For
Good workmanship is necessary to ensure that all perpend join jo ints ts are fu full lly y fi fill lle ed, th that bri bric cks are la laid id fr frog og up an and th that plastering is of a high standard.
a cavity wall, its weight (including plaster) must be at least 415kg/m2. Specifications for common types of wall which meet these requirements are given in Schedule 1 of Part E.
Of equal importance during the design stage is the reduction of flanking transmission and particular care is therefore necessary where floors are continued through separating walls and in detailing window and door openings.
TABLE 13 - DENSITY OF BRICKS REQUIRED
Wall Mat erial an d dimen sions (mm)
Plast er fi finish nish Thickness
Solid olid Wall
Brick rick size (mm) 6 5 x 10 2.5 x 2 1 5
Specified weight Specified at leas t (kg/m 2 ) includes fi finish nish
Numbe r of sid e s
Type
2
Lightweight
16 10
2
Gypsu Gy psu m
16 10
2
Lightweight
19 70
2
Gypsu Gy psu m
19 70
37 5
21 5mm
Cavity Wall
41 5
25 5mm
Note : The avera The rage ge weig ight ht of th the e bri bric ck to to be be us used de depend nds s on on ac achie iev vin ing g at at least th the e fol follo low win ing g va valu lue es for for mor orta tarr and and pl pla aste ter: r: (a) mortar- 1800 kg/m3 in joints 10 mm thick (b) plaster - lightweight 10 kg/m2 gypsum 17 kg/m2.
Aldersley Leisure Village, Wolverhampton, West Midlands Thro Th roc ckl kle ey Smoo ooth th Bu Buff ff & Atla Atlas Smoo ooth th Bl Blue ue
26
Avera ge de nsity of b rick t o b e used (kgm3)
Insulation THERMAL INSULATION Building Regulations currently require a U value of not more than
Early consultation with the cavity-fill manufacturer is advisable,
0.45W/m2 deg K for external walls. This may shortly reduce to
particularly in relation to exposure of the site. Standards of
0.35 or possibly 0.30 when using the elemental method of
workmanship and site supervision are critical as there is no residual
determination. This can readily be achieved with the range of
cavity to prevent rain penetrating across to the inner leaf.
insulants available. Examples of cavity construction with the
In partially filled cavity construction, a clear cavity of not less than
resultant U-values are shown in Table 14. The thermal conductivity ('k' value), for use in calculating the U-value of brickwork
50mm must be maintained in order to avoid bridging and to prevent the penetration of wind-driven rain.
construction, is given in the technical information that appears on Ibstock Brick’s Product Specification sheets that are available
In order to accommodate the insulation and provide the required
on request.
residual cavity, longer wall ties may be required together with special clips to fix the insulant securely to the inner leaf. Insertion of
Care is needed when considering a fully filled cavity since this can increase the likelihood of moisture penetration. When selecting an insulant for this application, reference should be made to the relevant British Standards or Agrement Certificates.
an insulant within a cavity does not affect the durability of the external brickwork, but to reduce the risk of rain penetration to the internal skin, mortar joints should be completely filled, using only curved recessed (bucket handle) or weatherstruck joints.
Wall ties to be bed ded level, with ith drips downward Insulation cut cleanly at extra wall ties
To minimi minimise se morta r inside cavity: 1. Bui uilld up one one course of bricks to form trough.
Inner face of oute r leaf to be stru ck clean before next ba tt is placed Insulation clippe lippe d to inner leaf
Insulation cut cleanly at extra wall ties
2. Clean Clean morta r from cavity cavity.. 3. Plac Placee next next cavity bat t. 4. Build Build up rema ining brickwork.
Board to collect ollect morta r dropp ings and prot ect cavity
All edges , (to be cut where neccessa ry) to be cleanly but t jointed Joints in insulation to be coursed with ith inner and oute r skin
Preferred Method:
Partially Filled Cavity
Build uild oute r leaf first to minimi minimise se the amo unt of mort ar in cavity.
Alternative Method:
Build uild inner leaf first.
Fully Filled Cavity
27
Insulation THERMAL INSULATION
TABLE 14 EXAMPLES OF CAVITY BRICKWORK CONSTRUCTION WITH APPROPRIATE THERMAL INSULATION U-VALUES U-value Outer Leaf (Brick Type & Density)
Cavity Insulation Examples
Inner Leaf - Type & Thermal Conductivity 'k' value)
Finish
0.2 7
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
50 mm Cl Clea ea r Cavity
10 0mm Lightweight block (0 .11 k)
50 mm dry li lining ning board on da bs (2.2 8R)
0.2 8
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
55 mm EPS Board (0 .02 6k) in 10 0mm cavity
10 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
0.2 8
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
0.2 8
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
0.3 0
Clay Facing Bri Bricks cks 14 00 kg/m3
0.3 0
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
50 mm Cl Clea ea r Cavity
10 0mm Medium de nsity block (0.1 9k)
50 mm dry li lining ning board on da bs (2.2 8R)
0.3 0
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
Bubble insulation in 60 mm Cavity NHBC HBC req uire 75 mm
15 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
0.3 0
Stock Bric Brickk 15 00 kg/m3
50 mm Inj Injecte ecte d foam (0 .01 8k)
Clay Cl ay Common (0.5 0k)
13 mm plast erb oard on da bs
0.3 2
Clay Facing Bri Bricks cks
60 mm EPS boa rd (0.0 33 K)
10 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
up to and incl including uding 20 00 kg/m3
in 10 0mm cavity
0.3 3
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
50 mm Epsx Board (0 .03 2K) in 10 0mm cavity
10 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
0.3 4
Clay Facing Bri Bricks cks 14 00 kg/m3
50 mm Cl Clea ea r Cavity 50 mm Insulation ba tt s (0 .02 4K)
Handma de Facing (0 .38 k)
Fair face
0.3 4
Clay Facing Bri Bricks cks
Bubble insulation in 60 mm Cavity
10 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
up to and incl including uding 20 00 kg/m3
NHBC HBC req uire 75 mm
Clay Facing Bri Bricks cks
50 mm Cl Clea ea r Cavity 10 0mm Medium density block block (0.19k) 38 mm Polyi Polyisocyanurate socyanurate boa rds (0.01 9K)
0.3 4
up to and incl including uding 20 00 kg/m
50 mm Cl Clea ea r Cavity 10 0mm Medium de nsity 48 mm Poly Polyisocy isocyanurat anurat e boards (0.0 19 K) block (0.1 9k) 60 mm EPS (0 .03 3K) in 10 0mm cavity
15 0mm Lightweight block (0 .11 k)
50 mm Cl Clea ea r Cavity Handma de Facing (0 .38 k) 50 mm Poly Polyisocy isocyanurat anurat e boards (0.0 19 K)
3
13 mm plast erb oard on da bs 13 mm plast erb oard on da bs Fair face
13mm plasterboard on dabs
0.3 5
Clay Facing Bri Bricks cks up to and incl including uding 20 00 kg/m3
50 mm Cl Clea ea r Cavi Cavity ty
10 0mm Medium density block block (0.17k)
0.3 8
Clay Facing Bri Brick ck 17 00 kg/m3
75 mm Mineral Wool ba tt s (0.0 36 k)
10 0mm Heavyweig Heavyweight ht Bl Block ock (1.1 2k)
13 mm plast erb oard on da bs
0.4 0
Handma de Facing 14 00 kg/m
50 mm Cl Clea ea r Cavity
Handma de Facing (0 .38 k)
Fair face
0.4 0
Stock Bric Brickk 14 00 kg/m
10 0mm Lightweight block (0 .11 k)
13 mm plast erb oard on da bs
0.4 1
Clay Facing Bri Brick ck 17 00 kg/m
65 mm Mineral Wool ba tt s (0.0 36 k)
Clay Cl ay Common (0.5 0k)
13 mm plast erb oard on da bs
0.4 2
Stock Bric Brickk 15 00 kg/m
75 mm fibre boa rds (0.0 40 k)
Clay Cl ay Common (0.5 0k)
13 mm plast erb oard on da bs
0.4 3
Clay Facing brick 16 00 kg/m
50 mm Cl Clea ea r Cavity
19 0mm Lightweight Bl Block ock (0.1 1k)
13 mm plast erb oard on da bs
3
40 mm dry lini lining ng boa rd on da bs (1 .73 R)
30 mm Phenolic Phenolic foam boards (0.01 8k)
50 mm Cl Clea ea r Cavity
3
50 mm cellular glass (0 .04 8k) 3
3 3
The inf The infor orm mat atio ion n in in the the ab abov ove ta tabl ble e is is for for gu guid idan anc ce onl only y an and d ind inde epe pend nde ent calc lcul ulat atio ions ns sh shou ould ld be mad ade e on in indi div vid idua uall con const stru ruc ctio tions ns.. Increasing the thickness of materials will also help to reduce the U-value. Methods of calculating U-values are under review and this may change the above results. ‘k’ values given are manufacturers figures.
Note: The pro The produ duct cts s ment ntio ione ned abo abov ve are us use ed for for exampl ple es onl only y an and d no no pre prefe fere renc nce e or reco com mmend ndat atio ion n is is int inte end nde ed. The Th ere is a lar large var arie iety ty of su supp ppli lie ers of si sim milar pro produ duc cts ts..
English Martyrs Church, Biddulph, Stoke-on-Trent Chesterton Red Smooth Chesterton Etruria Mixture Roughdales Albany Cream Westbrick Staffordshire Blue Brindle Smooth
28
Good Site Practice STORAGE
APPEARANCE
Bricks should be inspected on delivery. They should be unloaded
In order to achieve a uniform appearance throughout the building
directly onto a dry level area or scaffold and protected from the
and to avoid the possibility of patches or bands of differing shades,
weather. It is important not to overload floor slabs or scaffolds with
bricks should be used from a minimum of 3 packs at the same time.
large stacks of bricks.
Placing of bricks from one pack in one part of the wall should be
Ready-mixed lime:sand for mortar should be stored in a clean area on a hard, impervious surface, and protected from the weather. Extreme variations of moisture content will affect gauging.
avoided. Consideration should be given to constructing a 100 brick site reference panel in accordance with BS 3921:1985:Appendix F. Variations in the jointing profile due to poor workmanship or uncontrolled mortar mixes will adversely affect appearance.
MORTAR
CAVITY TIES
Th T he mor orta tarr sh shou ould ld be co corr rre ectl tly y pr prop opor orti tion one ed an and th thor orou ough ghly mixed. Nothing but clean water should be added later, and mortar should not be 'knocked up' after it has started to set.
All wall ties must be bedded to a minimum depth of 50mm, at right angles to the run of the wall and not pushed into the joint. Th T hey shou ould ld slo lope pe do dow wn tow toward rds s th the ou oute terr lea leaf. The The dri drip p must be located in the centre of the cavity and point downwards. Consideration should be given to the use of stainless steel ties.
Park & Ride Scheme, Rowley Regis, West Midlands Leicester Multi Red Stock, Roughdales Golden Brown Multi Rustic & Westbrick Staffordshire Blue Brindle Smooth
MORTAR PLASTICISERS AND AIR ENTRAINERS Under certain circumstances an air entrainer can be used to reduce
Globe Theatre, London Leicester Red Stock West Hoathly Handmade Multi Laybrook Bramber Multi Laybrook Sevenoaks Yellow Aldridge Staffordshire Georgian
the water requirement of the mortar by up to 50%. Th T his co con nsi side dera rabl bly y im impr prov oves th the pro produ duc cti tiv vit ity y in win inte terr - but but th the additive must be included in the mortar at initial mixing stage to ensure consistency and minimal strength loss. Ideally, air entraining agents should only be used in ready to use mortar.
J OI OINT NTS S All joints between bricks should be fully filled. Deep furrows in bed join jo ints ts and 'tipp tippe ed an and ta tail ile ed' pe perp rpe ends wil illl le let add addit itio ion nal wate terr pa pass through the brickwork and are not recommended. Unless otherwise instructed, mortar joints should be finished curved recessed (bucket handle) or weatherstruck. weatherstruck. J ointing as the work work proceeds is preferable.
29
Good Site Practice DPCS AND CAVITY TRAYS DPCs and cavity trays should should be sandwiched sandwiched in mortar. J oints to DPCs and cavity trays should be lapped a minimum of 100mm and sealed to prevent the downward movement of moisture. All cavity trays and combined lintels must have stop ends. Drainage weepholes shall be provided at not greater than 1 metre intervals and a minimum of 2 weepholes over each opening.
PROTECTION All walls must be covered when work stops, rain on new work can cause: Colour change of mortar
Lime stains
Saturation
Efflorescence
Bricks left uncovered on scaffolds are particularly prone to
Private Housing, Camden, London Funton Second Hard Stock
CAVITY INSULATION Cavities are designed to prevent water penetration to the inner leaf.
saturation by rain and snow. All covers must be secured to prevent them being dislodged by wind. Variation in the moisture content of mortars will frequently lead to colour changes; this is most marked in the case of darker coloured mortars, and particularly where joints have been tooled.
Full Fill Cavities Complete filling of a normal 50-75mm wall cavity with insulant can considerably increase the risk of rain penetration, the type of insulant and the exposure of the site should therefore be assessed carefully. Consideration to increasing the cavity width
All newly erected brickwork, and brickwork under construction must
may be appropriate in order to meet thermal and rain
be protected adequately from rain, snow and frost. In most cases
resistance requireme requirements. nts.
this is achieved by covering the wall head with a water resistant material, but problems can arise in some situations: e.g. in brickwork facing to concrete construction, where rain may frequently run off the concrete in quantity and penetrate behind the facing
Partial Filled Cavities Maintain the specified cavity, placing insulation batts against the inner leaf and secure them with specially designed wall tie clips.
brickwork. In this situation a water resisting material is normally fixed to the vertical surface of the concrete and draped over, and
Where a clear airspace of a minimum of 50mm is maintained,
clear of, the brickwork, being lifted as work proceeds.
partial fill insulation does not increase the risk of rain penetration.
Hessian is frequently used as an insulating layer in sunny weather,
Where cavity fill insulation is used the DPC cavity tray must be
but it is useless if it becomes wet. Apart from the loss of its value
provided with stop ends to prevent water running into the cavity
as insulation, hessian which is soaking wet will frequently cause
and saturating the insulation. Achieving good workmanship
serious staining and efflorescence of the brickwork. It must,
is essential.
therefore, be covered with plastic or other waterproof materials in adverse conditions. Every opportunity must be taken to allow the brickwork to dry out when conditions permit. To encourage this, the cover should be supported clear of the face(s) of the wall, either by laying it over a wooden framework or over projecting bricks, so that ventilation can take place beneath the cover. Mortar splashing and staining of brickwork will also occur in wet weather unless the inner scaffold board is turned back when work is left.
30
Good Site Practice BRICKLAYING IN WINTER Bricklaying should be discontinued when the brickwork temperature falls below 3°C, and when frost is imminent. Although some guidance can be obtained from the air temperature, it is the temperature of the brickwork that is important. In the absence of a suitable thermometer, some indication of whether or not the brickwork is below freezing point may be obtained by applying a small quantity of water onto the bricks (e.g. by paintbrush or similar). If the film of water freezes, then clearly bricklaying should not commence.
Mortar Strength Although the stronger, more dense mortars (designations (i) and (ii)) are more resistant to freezing and are normally used in more exposed building situations, less strong mortars (designation (iii)) are frequently used for the external walls of buildings in more sheltered situations. A 1:1:6 cement:lime:sand mortar has adequate long term durability provided that it is correctly gauged, but some additional protection may be needed if it is to resist freezing at an early age, when it is still ‘green’ and before adequate strength has developed. The development of strength takes place more slowly at low temperatures.
The use of accelerators accelerators such as 'anti- freeze' ag ag ents is not r ecomm ecommended. ended.
Adhesion In its simplest terms, bond relies on the binder paste in the mortar flowing into the pore structure of the brick. The mortar must, however, retain sufficient water for its hydraulic properties to develop and, hence for setting to occur. In winter, because the brickwork dries more slowly, the mortar will require less water. The mortar should, therefore be as stiff as possible whilst retaining sufficient flexibility to allow alignment to take place. Laid bricks should not be 'trued up' once initial stiffening has taken place since this will permanently break the mortar bond.
Winter Protection Stocks of all materials, particularly bricks, should be protected from rain, snow and frost and from ground contamination, and splashing by passing vehicles.
Private Housing, Chester, Cheshire Westbrick Axminster Blend Cattybrook Cheddar Red Westbrick Staffordshire Slate Blue Smooth
31
Other Sources of Reference Th T he fol follo low win ing g sou sourc rce es of of re refe fere ren nce li lis st the the pri prin ncip ipa al Bri Briti tis sh Sta tan nda dard rds s
BS Specifications for Insulation Systems
for materials, design, workmanship and insulation systems, and these should be consulted as appropriate. Reference should also be
BS 3837:
Part 1 1996 Specification for boards
made, as necessary, to the relevant sections of The Building
manufactured from expandable beads
Regulations 1991, as amended. BS 4841:
BS 743:
BS 56 5617 17::
cavity walls with masonry or concrete inner
BS 12 1243 43::
and outer leaves
1996 Spe Speci cifi fica catio tion ns for for build buildin ing g san sands ds fr from om natural sources
BS 56 5618 18::
inner and outer leaves) by filling with
wall construction 1985 Specification for clay bricks
BS 4721:
1986 Sp Specification for re ready-mixed
urea-formaldehyde (UF) foam systems BS 66 6676 76::
Part 1 1994 Specification for man-made
1990 19 90 Specification for sh shapes and sizes of
mineral fibre batts (slabs)
special bricks BS 5628:
Part 2 1994 Code of practice for installation
Code of Pr Practice for us use of masonry.
of batts (slabs) filling the cavity
Part 1 1992 Structural use of unreinforced mas masonry. onry.
BS 82 8208 08::
insulants Part 1 1985 Existing traditional
and pre-stressed masonry.
cavity construction
Part 3 1985 Materials and components,
BS 6093:
1992 Guide to selection of constructional sealants
BS 63 6398 98::
1983 19 83 Specification for bi bitumen damp pr proof courses for masonry
BS 6515:
1996 Sp Specification for po polyethylene damp-proof courses for masonry
BS 80 8000 00::
Also Useful
1993 De Design of Jo Joiints and Jo Joiinting in Building Construction
BS 6213:
Guide to.a .as ssessment of suitability of external cavity walls for filling with thermal
Part 2 1995 Structural use of reinforced
design and workmanship.
Thermal insula lattio ion n of cavit ity y walls using man-made mineral fibre batts (slabs)
building mortars BS 47 4729 29::
1996 19 96 Code of of pr practice for th thermal in insulation of cavity walls (with masonry or concrete
1978 19 78 Specification for metal ti ties fo for ca cavity
BS 3921:
1996 19 96 Specif ific ica atio ion n for urea-f -fo ormald lde ehyde (U (UF F) foam systems suitable for thermal insulation of
1970 Sp Specification for materials for da dampproof courses
BS 1199/12 1199/1200: 00:
Part 1 1993 Laminated board for general purposes
BS Specifications for Materials, Design and Workmanship
Expanded polystyrene boards
Workmanship on building sites. Pa Part 3 19 1989 89
BRE Thermal Insulation:Avoiding Risks BDA Design Note Number 10: Designing for Movement in Brickwork BDA Design Note Number 11: Improved Standards of Insulation BDA Building Note I :Brickwork Good Site Practice BDA Building Note 2:Cleaning of Brickwork BDA Guide to Successful Brickwork Guidance on the preparation of specifications can be obtained from Th T he Na Nati tion ona al Bu Buil ildi din ng Speci cifi fic cati tion on and fro from m NH NHBC BC Sta tan ndard rds s.
Code of Practice BS 81 8104 04::
BS 8215:
1992 19 92 Code of Pr Pra actic ice e for assessin ing g exposure
Ibstock Brick Design Guides
of walls to wind-driven rain
Designing for Movement
1991 Code of Practice for design and
Freestanding Walls
installation of damp-proof courses in
DD 140:p 140:par artt 2
Th T he Ea Easy Ar Arch ch
masonry construction
Plinths
Reco com mmen enda datio tion ns for for Des Desig ign n of of Wa Wall Tie Ties s
Corbelling Copings & Cappings in Clay Brickwork and Cast Stone
32
Design and Technical Services Specialist advice, precise information, speed of response... in a word service. Our aim is a simple one: to ensure that our standards of service are as exceptional as our range of products.
Design Service
Additional Notes Ibst ock Bri Brick ck s Design and Technical Services Depa rtme nts can ad vise on the correct spe cif cification ication of mort ar mixes and joint profil profiles. es.
Th T he Ibs Ibsto tock ck Br Bric ick k De Desig ign n Adv Advis isor ory y Serv rvic ice e is is Qu Quali lity ty As Ass sure red d to to ISO 9001. Our in-house Design Advisors can offer practical advice on issues as wide ranging from movement control, support of corbels and modelling features, water penetration to assistance with the production of architectural detailing. Ibstock Brick’s Design Service is pleased to advise on the design and use of both standard and purpose-made special shape bricks.
Specifiers pecifiers should consult man manufact ufacturers urers of DPC mat erials, sea lant s, fi fixings xings an andd reinforcement for ad vic vicee on the use of the se prod ucts ucts.. Inte rmed iat iatee DPC DPCss must be use usedd where cavity fi fill ll insulation nsulat ion is spe cif cified ied in buildings exceed ing two storeys. Some fil fills ls are not recommended in areas of severe exposure.
By detailing and planning the use of special shape bricks at an early stage, delivery schedules can be prepared appropriately, thus helping to ensure the availability of special shape bricks when required on site. Additionally, early consultation at the design stage can serve to avoid potential detailing problems, resulting in more cost effective solutions.
Wall ties must comply wi with th BS 1 24 3 and DD 14 0 an andd should be install installed ed fully fully bedd ed in a ccordance with with the man ufactu ufacturer's rer's recomme nda tions, pa rticularly where the y are use usedd to locat e pa rtia rtiall fi fill ll cavity insulation nsulat ion mat erials. It is ad visable to ensu ensure re tha t the wi widt dt h of the clear
Technical Service To he help cov ove er th the com compl ple ete spect ctru rum m of te tech chnic ica al qu queri rie es,
cavity is not less tha n 5 0m 0mm. m. Specifiers pecifiers are invi invite te d to discuss the ir pa rticular
Ibstock Brick's Technical Service offers a range of skills, including
requirement eq uirement s wi with th Ibst ock Bri Brick ck s Design and Technical
technical and practical on-site advice regarding the properties and
Services Depa rtme nts nts,, who wi will ll ad vise on the
performance of bricks and brickwork. Ibstock will be delighted to
ap plication or mod modif ification ication of any of the de deta ta il ilss
arrange tailor-made technical training seminars, and to provide
contained ont ained in this li lite te rat ure.
up-to-the minute information on British Standards and Codes of Practice.
Although the information in this publication, and any other information provided by Ibstock Brick is believed to be accurate, correct and complete, and not misleading, no reliance should be placed upon its contents as being applicable to any particular circumstances. Any advice, opinion, information or other contents are published only on the footing that the company, its servants or agents or contributors to this publication shall be under no liability whatsoever in respect of its contents or for any loss howsoever caused.
33
Products and Services
RANGE BROCHURE Being our most useful and requested piece of literature, the new range brochure has recently been updated and improved. Private Housing, Loxley, Warwickshire Roughdales Chester Red Blend
Th T he bro broc chure co con nta tain ins s ov over 350 350 bricks, illustrated in panels, along with relevant technical data. All bricks that are available in imperial sizes, are clearly marked with an
PAVER RANGE BROCHURE
symbol, for ease of reference. New products are also clearly
marked, with a "new product" label next to each panel.
Ibstock Brick manufactures a range
On every page is a relevant project photograph. There is a healthy
of clay pavers and fittings in various
balance of commercial, public and private buildings, and many
colours to suit differing
projects show the use of good detailing, specials and
applications.. This brochure applications
complementary colour combinations.
illustrates panels of these pavers Th T he ba back cov cover ha has con conta tact ct in info form rmati tion on fo forr ea each sa sale les s off offic ice e,
alongside photographs of the
illustrating their location, as well as factory locations on a map.
SPECIAL SHAPED BRICKS BROCHURE Another key piece of Ibstock Brick literature is our Special Shaped Bricks brochure. This catalogue illustrates the range of popular, standard specials on offer from Ibstock and is arranged in an easy to use format.
pavers in work. Toward rds s th the ba back of th the e bro broc chur ure e are are cle lea ar lay layin ing g in inst stru ruc cti tion ons, s, to to help with your paving project.
HATHERNWARE BROCHURE Ibstock Hathernware has been synonymous with high quality
Th T he bro broc chure is arr rra anged in in se sect ctio ion ns by by shape, wh whic ich h are are cl cle earl rly y
terracotta and faience for over a
identified with colour coded strips. Each section
century. The majority of work is
shows 3D drawings of the
purpose-made, offering the designer
indivdual shapes, the brick
almost unlimited design freedom.
shapes in work, associated dimension table and relevant
Bespoke architectural terracotta and
photography of the products in
faience has contributed to the
built schemes.
refurbishment of many famous buildings, including the British Museum of Natural History.
All designed to give our customers
A new brochure is available, which shows examples of what can
all the relevant information to
be achieved by using terracotta and faience - to create
pursue their special shape enquiry.
unique buildings.
If you wi wish sh to rece receive ive a ny of ou ourr bro brochure chure s, ca call ll ou ourr Liter L iteraa tu ture re Hotline on : 0 8 7 0 9 0 3 4 0 3 0 34
Products and Services
WEBSITE Th T he Ibs Ibsto tock ck Br Bric ick k websit ite e pro prov vid ide es an an on on-li -lin ne up up to to da date gu guid ide e to to the multitude of products and services now available from Ibstock. With its simple menu and easy navigation, you can gain fast access to practical and technical details, news and new products,
SAMPLES SERVICE Ibstock Brick's sample service is available for all our bricks and pavers. We offer brick/paver panels and brick/paver boxes
a summary of our product range on the Brick Selector button, and numerous project case studies. In addition useful DXF files
for all products.
can be downloaded directly Our lates l atestt innov innovation ation is the new
to your CAD application to
Ibstock Brick Sample Card, which
assist with the design of
is available for our best selling
brickwork detailing.
products. These Sample Cards are high quality photographs
CD ROM
of our products on durable
Our latest communication
card, for easier selection,
innovation is the Ibstock CD Rom (version 3). It contains a brick
storage and display.
selector, which allows the user to match their requirements along To ord orde er sa sampl ple es, ple please con conta tac ct
with their technical properties and project photographs. A section
your local Representative or Sales Office, who will be pleased to
on special shaped bricks includes a high
help. (Sales Office numbers are listed on the back of this guide).
quality video on the production and application of specials and further
QUALITY ASSURANCE
drawings on how and where to make the
Ibstock Brick is committed to the highest standards of quality. It
best use of specials. It also contains
operates comprehensive quality management systems in compliance
contact details, location maps and the
with BS EN ISO 9001:1994, maintains BSI Registered Firm status
facility to order up to date literature.
and holds Kitemark licences.
DESIGN MAGAZINE Ibstock Brick's Design magazine is a regular publication which is dedicated to good architectural detailing. Featuring a summary of the projects, photographs and architects' working drawings, the magazine is free of charge. To receive your regular copy contact the Literature Hotline on 0870 903 4030.
Private Housing, Hale, Cheshire Ashdown Cottage Mixture Cattybrook Cheddar Red
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