section 13 (masonry) - qcs 2010

8/18/2019 Section 13 (Masonry) - Qcs 2010

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Q a t ar P r o j e c t M an a g em en t

QCS 2010 Section 13 Part 1 General

QCS 2010

1. GENERAL ...................................................................................................... 2

1.1 INTRODUCTION ........................................................................................... 2

1.1.1 Scope 2

1.1.2

References 2

1.1.3 Definitions 2

1.2 APPROVAL OF SUPPLY SOURCE .............................................................. 2

1.2.1 General Requirements 2

1.3 SAMPLES, TESTING AND SUBMITTALS .................................................... 2


1.3.2 Sample Panels 3

1.4 PRODUCT HANDLING .................................................................................. 3

1.4.1 Storage of Materials 3

1.5 WORKMANSHIP ........................................................................................... 3


1.6 CLEANING ..................................................................................................... 3


1.6.2 Brickwork 4

1.6.3 Concrete Masonry Units 4





QCS 2010

1. GENERAL

1.1 INTRODUCTION

1.1.1 Scope

1 This Section covers the products, erection and all associated accessories for construction ofconcrete and clay masonry unit blockwork as well as requirements for glass block units,gypsum units, and stonework.

2 Related Sections and Parts are as follows:

Section 5 ConcreteSection 15 Thermal Insulation of BuildingsSection 24 Finishes to BuildingsSection 26 Painting and Decorating

1.1.2 References

1 The following standards referred to in this Part:

BS 6100 Glossary of building and civil engineering terms

1.1.3 Definitions

1 Definitions used in this Section follow the requirements of BS 6100 unless otherwise stated.

1.2 APPROVAL OF SUPPLY SOURCE

1.2.1 General Requirements

1 All products supplied under this Section must be obtained from an approved source.

2 The Contractor will not be permitted to change his source of supply without the permission ofthe Engineer.

1.3 SAMPLES, TESTING AND SUBMITTALS


1 Samples of each type of masonry unit to be used shall be submitted to the Engineer forapproval before use. All subsequent units are to be up to the standard of the approvedsamples.

2 Initially, twelve (12) units will be selected by the Engineer from the first batch of unitsmanufactured or delivered. The units shall be delivered by the Contractor to an approvedindependent testing laboratory, or if the Engineer so directed, to the Government MaterialsTesting Laboratory.

3 The sample is to be accompanied by the following written information:

(a) type of unit(b) means of identification of unit(c) name of manufacturer(d) type of masonry units making machine(e) capacity of plant and present stocks available(f) certificates stating that the units are suitable for the purpose for which they are to be

used.





QCS 2010

4 A number of units to indicate colour range for exposed work to be submitted to the Engineerfor approval prior to commencement of the Works.

5 Further samples will be selected and tested as directed by the Engineer.

6 The Contractor shall submit details of his proposed methods for reinforcement to the

Engineer for approval. The Contractor shall also submit details of his proposed methods forconstructing lintels, anchors and anchor channels.

1.3.2 Sample Panels

1 Before any fair or faced masonry work is commenced, the Contractor is to erect one samplepanel, size 1800 mm long x 2000 mm high, of each type of finish to be used.

2 The panels should incorporate a typical opening detail and a typical corner detail, and atypical movement joint.

3 Before starting face brickwork, the Contractor shall lay up a sample panel 2 m long by 1 mhigh for the Engineer’s approval. Random piles of brick as delivered to the Site shall be used.

Brickwork to be incorporated in the Works is to match original sample brickwork panels asapproved by Engineer. Sample panels must not be removed until directed by Engineer.

1.4 PRODUCT HANDLING

1.4.1 Storage of Materials

1 Masonry units delivered to the Site are to be carefully unloaded and handled so as to preventchipping and breakage. Tipping of units will not be allowed.

2 The units are to be stacked on a level area in an orderly manner on planks or other suitablesupports to ensure that they are free from contact with the ground. Stored units shall be keptunder waterproof covers.

3 Packaged materials shall be stored in their original containers.

1.5 WORKMANSHIP


1 Tops of walls shall be covered with waterproof covering when the work is not in progress.

2 When starting or resuming work, loose mortar and foreign materials shall be cleaned fromthe top surface of the work. Surfaces of clay type masonry shall be wetted before resumingwork.

3 Newly laid blockwork and brickwork shall be protected from the harmful effects of sunshine,rain, drying wind, and surface water.

4 Blockwork shall be water cured for a minimum of three days.

5 Units that will be exposed to view in finished work shall be supplied in adequate quantities topermit selection and mixing of brick from several deliveries in advance of laying. Units shallbe exposed to the atmosphere for minimum of two weeks before laying.

1.6 CLEANING


1 Clean exposed masonry surfaces on completion. Protect material liable to damage.





QCS 2010

1.6.2 Brickwork

1 Cut out defective exposed new joints to a depth of approximately 20 mm and repoint.Remove mortar droppings and other foreign substances from the wall surfaces. First wetsurfaces with clean water and then wash down with a solution of soapless detergent speciallyprepared for cleaning brick. Brush with a stiff fibre brush and immediately after, hose down

with clean water. Clean surfaces from any traces of detergent, foreign streaks or stains ofany nature. Protect adjoining construction materials during cleaning operations. Use ofmuratic acid for cleaning brickwork is prohibited.

1.6.3 Concrete Masonry Units

1 Immediately following setting, brush exposed surfaces free of mortar or other foreign matter.

END OF PART




QCS 2010 Section 13 Part 2 Mortar and Grout Page 1

QCS 2010

2. MORTAR AND GROUT ................................................................................. 2

2.1

GENERAL DESCRIPTION ............................................................................ 2

2.1.1

Scope 2

2.1.2

References 2

2.2 MORTAR MATERIALS .................................................................................. 2

2.2.1

Preparation Requirements 2

2.2.2 Cement 3

2.2.3

Aggregates 3

2.2.4 Water 3

2.2.5

Lime 3

2.3

EPOXY........................................................................................................... 3

2.3.1

General Requirements 3

2.4

HIGH BOND ................................................................................................... 3

2.5 GROUTS........................................................................................................ 4


2.6 PIGMENTS FOR COLOUR ........................................................................... 4

2.6.1


2.7

TUCK POINTING ........................................................................................... 4

2.7.1

General 4

2.7.2 Protection 5

2.7.3

Existing Mortar Joints 5

2.7.4

Installation of Tuck Pointing Mortar 5

2.7.5 Tooling of Joints 5

2.7.6

Replacement of Masonry Units 5

2.7.7 Cleaning 5





QCS 2010

2. MORTAR AND GROUT

2.1 GENERAL DESCRIPTION

2.1.1 Scope

1 This Section specifies mortar and grout for masonry, glass blocks and stone work.

2 Related Parts and Sections are as follows:

This SectionPart 2 Unit MasonryPart 3 Reinforced Unit MasonryPart 5 Masonry Laying

Section 5 Concrete

2.1.2 References

1 The following standards are referred to in this Part:

ASTM C270 ---- Standard Specification for Mortar for Unit Masonry

BS EN 459-1 -- Building lime. Definitions, specifications and conformity criteriaBS EN 934-3 -- Admixtures for concrete, mortar and grout. Admixtures for masonry mortar.

Definitions, requirements, conformity and marking and labellingBS EN 998-2 -- Specification for mortar for masonry. Masonry mortarBS EN 12004 -- Adhesives for tiles. Requirements, evaluation of conformity, classification

and designationBS EN 12878 -- Pigments for the colouring of building materials based on cement and/or

lime. Specifications and methods of testBS EN 13888 -- Grout for tiles. Requirements, evaluation of conformity, classification and

designation

PD 6472 -------- Guide to specifying the quality of building mortars

PD 6678 -------- Guide to the specification of masonry mortar

2.2 MORTAR MATERIALS

2.2.1 Preparation Requirements

1 The required class of mortar, together with the type of mix, shall be as described inthe Project Documentation.

2 Mortar shall be mixed only as and when required in the relevant proportionsindicated in Table 2.1, until its colour and consistency are uniform. The constituentmaterials shall be accurately gauged allowance being made for bulking of sand.

Table 2.1Mortar Mixes

Nominal Mix by mass and their compressive strength

Class Cement (C), Lime (L) &Sand (S) with or without

entrainment (kg)

Cement (C) & Sand (S)with or without

entrainment (kg)

Compressive strength at 28 days

N/ mm2

C L S C S

M2 70 50 740 85 775 2

M4 105 35 725 110 755 4

M6 135 25 700 155 710 6

M12 190 20 655 190 675 12





QCS 2010

3 The inclusion of mortar plasticisers will not be permitted without approval of theEngineer.

4 All mortar shall be conveyed fresh to the works as required for use. Mortar whichhas begun to set or which has been site-mixed for a period of more than one hourin the cases of Classes M2, and M6, and two hours in the case of classes M4 and

M12 shall not be used.

5 Plasticizing and set retarding mortar admixtures shall comply with BS EN 934-3and shall be supplied with instructions for use.

6 Ready-mixed lime: sand for mortar and ready-to-use retarded mortar shall complywith the relevant provisions of BS EN 998-2 or ASTM C270.

2.2.2 Cement

1 Cement is to comply with the relevant provisions of Section 5, Concrete.

2 Mortar for use in contact with the ground will be mixed using sulphate resistant

cement and comply with the relevant provisions of Section 5, Concrete.

2.2.3 Aggregates

1 Aggregates are to generally comply with the relevant provisions of Section 5,Concrete.

2.2.4 Water

1 Water is to comply with the relevant provisions of Section 5, Concrete.

2.2.5 Lime

1 Lime for mortar shall be in the form of lime putty, complying with the relevantprovisions of BS EN 459-1.

2.3 EPOXY


1 Epoxy grouts shall comply with the relevant provisions of BS EN 12004, BS EN13888 as applicable.

2.4 HIGH BOND

1 Mortar mixture is to consist of, by volume, one-part Portland cement, three-partssand with addition of water and liquid acrylic resin.

2 The mortar will have the following properties when tested in accordance with therelevant provisions of PD 6678:

(a) compressive strength : minimum 20 N/mm², using 50 x 50 x 50 mm cubes(b) tensile strength : minimum 4 N/mm², using the 25 x 25 x 25 mm briquettes(c) flexural strength : minimum 6 N/mm², using flexural bar(d) brick bond strength : minimum 3 N/mm², using crossed brick.





QCS 2010

2.5 GROUTS


1 The required class of mortar, together with the type of mix, shall be as described inthe Project Documentation.

2 Cement grout shall be mixed in the relevant proportions indicated in the Table 2.2using the minimum quantity of water to ensure the necessary fluidity and to renderit capable of penetrating the work.

Table 2.2

Grout Mixes

ClassNominal Mix by Mass

Cement Sand pfa

G1 1 - -G2 1 3 -

G3 1 10 -

G4 1 - 10

G5 1 - 4

G6 1 - ½

3 Cement grout shall be used within one hour of mixing, except where containing aretardant admixture.

4 Sulfate-resisting cement shall not be used as a constituent of grouts containingpulverised fuel ash.

5 Grout to have a compressive strength of 17,500 kPa at 28 days.

2.6 PIGMENTS FOR COLOUR


1 Mineral pigments only to be used.

2 Any pigments used to colour cement or cement products should meet therequirements of BS EN 12878.

3 Pigments shall be inert, stable to atmospheric conditions, alkali resistant and waterinsoluble.

2.7 TUCK POINTING

2.7.1 General

1 This Clause specifies the requirements for tuck pointing of existing masonry andstone work.

2 Mortars to comply with the relevant provisions of Clause 2.2 of this Part.





QCS 2010

2.7.2 Protection

1 Newly pointed joints are to be protected from rain, until pointed joints aresufficiently hard enough to prevent damage.

2.7.3 Exist ing Mortar Joints

1 The existing mortar joints (both bed and head joints) are to be cut out and removedby means of a toothing chisel or a special pointer’s grinder, to a uniform depth of20mm, or until sound mortar is reached. Care is to be taken so as not to damagethe edges of existing masonry units.

2 Remove all dust and debris from the joints by brushing, blowing with air or rinsingwith water.

2.7.4 Installation of Tuck Pointing Mortar

1 Immediately prior to application of mortar, the joints to be tuck-pointed are to bedampened. After dampening, the masonry units should be allowed to absorb all

surface water prior to application of pointing mortar

2 The mortar is to be tightly packed into the joints in thin layers, approximately 5 mmthick maximum.

3 Each layer should become “thumbprint hard” before applying the next layer.

4 The final layer is to be flush with surfaces of masonry units. When the mortarbecomes “thumbprint hard”, joints can be tooled.

2.7.5 Tooling of Joints

1 A jointing tool is to be used to produce a smooth, compacted, concaved joint.

2 Tool joints in patch work are to be finished to match the existing surrounding joints.

2.7.6 Replacement of Masonry Units

1 Mortar joints surrounding masonry units which are to be removed and replaced areto be cut-out with a toothing chisel. The units which are to be removed may bebroken and removed, provided that the surrounding units to remain are notdamaged. Once the units are removed, old mortar is to be carefully chiselled out,and all dust and debris are to be swept out with a brush. If the units are located ina cavity wall, care should be exercised not to allow debris to fall into the cavity.

2 The surface of the surrounding units are to be dampened before the new units areplaced. The existing masonry should absorb all surface moisture prior to theinstallation of the new replacement units. The contact surfaces of the existingmasonry and the new replacement masonry units are to be buttered with mortar.The replacement masonry units should be centred in the opening and pressed intoposition. Excess mortar is to be removed with a trowel head and bed joints are topointed. When the mortar becomes “thumbprint hard”, joints are to be tooled.

2.7.7 Cleaning

1 Exposed masonry surfaces shall be cleaned on completion.

2 Mortar droppings and other foreign substances shall be removed from the wallsurfaces.

3 Surfaces shall be wetted with clean water, and then washed down with a solutionof soapless detergent specially prepared for cleaning masonry. Brush with stifffibre brushes while washing, and immediately thereafter hose down with clean





QCS 2010

water. Free clean surfaces from any traces of detergent, foreign streaks or stainsof any nature.

4 Protect adjoining construction materials during cleaning operations.

5 Use of muratic acid for cleaning brickwork is prohibited.

END OF PART




QCS 2010 Section 13 Part 3 Accessories Page 1

QCS 2010

3. ACCESSORIES ............................................................................................. 2

3.1 GENERAL DESCRIPTION ............................................................................ 2

3.1.1 Scope 2

3.1.2

References 2

3.2 ANCHOR AND TIE SYSTEMS ...................................................................... 2

3.2.1 Cavity Wall Ties 2

3.3 CONTROL JOINTS ........................................................................................ 2

3.3.1 Movement Joints 2

3.4 JOINT REINFORCEMENT ............................................................................ 3

3.4.1 Reinforcement for Concrete Block Masonry 3

3.5 LINTELS ........................................................................................................ 3

3.5.1

Precast or Cast In-situ Lintels 3





QCS 2010

3. ACCESSORIES

3.1 GENERAL DESCRIPTION

3.1.1 Scope

1 This Part specifies anchor and tie system, joint control, reinforcement and lintels associatedwith masonry works.


This SectionPart 1 GeneralPart 5 Masonry Laying

Section 1 GeneralSection 6 Concrete

3.1.2 References

1 The following standards are referred to in this Part:

BS EN 845-1:2003+A1:2008 Specification for ancillary components for masonry. Ties,tension straps, hangers and brackets

BS EN 10346:2009 ----------- Continuously hot-dip coated steel flat products. Technicaldelivery conditions

BS EN 10143:2006,----------- Continuously hot-dip coated steel sheet and strip. Toleranceson dimensions and shape

BS EN 13658-2:2005 --------- Metal lath and beads. Definitions, requirements and testmethods. External rendering

GSO ISO 4998:2007, --------- Continuous hot-dip zinc-coated carbon steel sheet of structural

quality

ISO 14657:2005, -------------- Zinc-coated steel for the reinforcement of concrete

3.2 ANCHOR AND TIE SYSTEMS

3.2.1 Cavity Wall Ties

1 Cavity wall ties to comply with BS EN 845-1 and be of one of the following types as directedby the Engineer or as noted in the Project Documentation:

(a) Butterfly wall tie fabricated from stainless steel wire(b) Double triangle wall tie fabricated from stainless steel wire

(c) Vertical-twist tie fabricated from stainless steel strip.

2 Ties fabricated from wire are not be used for cavities exceeding 75 mm.

3 All connections between masonry walls or partitions and concrete columns or walls shall bemade using propriety stainless steel ties secured to stainless steel fixing channels embeddedin the concrete.

3.3 CONTROL JOINTS

3.3.1 Movement Joints

1 Movement joints to be 12 mm wide and formed where indicated or where continuous runs of

block walling exceed 8 metres in length.

http://shop.bsigroup.com/en/ProductDetail/?pid=000000000030153926


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http://std.gso.org.sa/standards/public/standardsList.seam?actionMethod=public%2FstandardsList.xhtml%3ApublicPurchase.loadStandardDetails%28%29&cid=1556&dataModelSelection=std%3ApublicStandards%5B0%5D








QCS 2010

2 The joints are to be straight and vertically formed with uncut faces of the blocks to each sideand filled with an approved compressible material manufactured specifically for building intomovement joints.

3 External joints are to be sealed with a mastic compatible with the joint filling material whenthe block walling is thoroughly dry and the joint surfaces have been cleaned with a wire

brush or mechanical tool.

4 A primer is to be applied to the joint surface if specified by the manufacturer of the mastic.

5 Mastic sealing to unfilled movement joints to be on an approved foam backing strip placed toensure the correct depth of sealant.

3.4 JOINT REINFORCEMENT

3.4.1 Reinforcement for Concrete Block Masonry

1 Expanded mesh lath reinforcement is to be fabricated from minimum nominal thickness 0.3mm as per BS EN 13658-2:2005 , or welded wire lath or mesh with a minimum weight of

0.87 kg/m² as per BS EN 13658-2:2005; or Zinc coated steel with one of the surface qualityTypes "B" or “C” with minimum zinc coating - 225 g/m² as per BS EN 10346:2009, asdirected by the Engineer or Project Documentation.

2 The widths of reinforcement for various wall thicknesses to comply with Table 3.1.

Table 3.1

Expanded Steel Mesh Joint Reinforcement Widths

Block Thickness

(mm)

Reinforcement Width

(mm)

100 50

150 60

200 110

3.5 LINTELS

3.5.1 Precast or Cast In-situ Lintels

1 Precast or cast in-situ lintels to be manufactured in accordance with the relevant provisions

of Section 5.

2 An open joint not less than 12 mm are to be left between the ends of precast or cast in-situconcrete lintels and the blocks adjacent to these ends. These open joints should be left aslong as possible during construction and not be filled in until plastering or other worksnecessitate such filling.

3 Lintels are to have a minimum end bearing of 200 mm.

END OF PART




QCS 2010 Section 13 Part 4 Unit Masonry Page 1

QCS 2010

4. UNIT MASONRY ........................................................................................... 2

4.1 GENERAL ...................................................................................................... 2

4.1.1 Scope 2

4.1.2 References 2

4.2 CLAY MASONRY UNITS ............................................................................... 2

4.2.1 Clay Bricks 2

4.2.2 Clay Blocks 2

4.2.3 Classification of Clay Masonry Units 2

4.2.4 Requirements of Clay Masonry Units 3

4.2.5 Marking of Clay Blocks 4

4.2.6 Testing of Clay Blocks 4

4.2.7 Criteria of Technical Conformity of Clay Blocks 5

4.3 CALCIUM SILICATE BRICKS ........................................................................ 5

4.3.1


4.4 CONCRETE MASONRY UNITS .................................................................... 5

4.4.1 Concrete Blocks 5

4.4.2 Manufacture of Concrete Blocks 7

4.4.3 Block Dimensions 7

4.4.4 Precast Concrete Bricks 8

4.5 GLASS UNITS ............................................................................................... 8


4.5.2 Submittals 8

4.5.3

Material Storage and Handling 8

4.5.4 Laying 8

4.6 GYPSUM UNITS ............................................................................................ 9


4.7 STONE WORK .............................................................................................. 9


4.7.2 Anchorage Devices 9

4.7.3 Mortar 10

4.7.4 Fabrication 10

4.7.5

Installation 10

4.7.6 Wall Cladding 10

4.7.7 Paving and Flooring 11

4.7.8 Erection Tolerances 11

4.7.9 Submittals 11

4.7.10 Visual Mock-ups 11

4.8 CAST STONE .............................................................................................. 12


4.8.2 Submittals 12

4.8.3 Product Delivery, Storage and Handling 12

4.8.4

Anchorage Devices 12





QCS 2010

4. UNIT MASONRY

4.1 GENERAL

4.1.1 Scope

1 This Part specifies clay and concrete masonry units.


This SectionPart 1 GeneralPart 2 Mortar And GroutPart 3 AccessoriesPart 5 Masonry Laying

Section 1 GeneralSection 5 ConcreteSection 15 Thermal Insulation of Buildings

4.1.2 References1 The following standards are referred to in this Part:

ASTM C270 -------- Standard Specification for Mortar for Unit Masonry ASTM C1364 ------ Standard Specification for Architectural Cast Stone

BS 187 -------------- Calcium silicate bricksBS 1217 ------------ Cast stoneBS 6073-2 ---------- Precast concrete masonry units. Guide for specifying precast concrete

masonry units

BS EN 771 --------- Specification for masonry unitsBS EN 772-2 ------ Methods of test for masonry units. Determination of percentage area of

voids in masonry units (by paper indentation)BS EN 771-3 ------ Specification for masonry units. Aggregate concrete masonry units(dense and light-weight aggregates)

BS EN 771-5 ------ Specification for masonry units. Manufactured stone masonry units

EN 771-1 ----------- Specification for masonry units. Clay masonry unitsEN 771-2 ----------- Specification for masonry units. Calcium silicate masonry unitsEN 998-2 ----------- Specification for mortar for masonry. Masonry mortar

PD 6678 ------------ Guide to the specification of masonry mortar

4.2 CLAY MASONRY UNITS

4.2.1 Clay Bricks

1 A clay brick is a masonry unit not exceeding 290 mm in length and 115 mm in height.

2 Semi-solid bricks are bricks having up to 25 % holes or cavities of their gross volume.

3 Cellular bricks contain the same voids as hollow bricks but with the cavities closed at oneend.

4 Clay bricks to conform to the requirement of EN 771-1.

4.2.2 Clay Blocks

1 A clay block is a masonry unit which exceeds in any of its normal dimensions the maximumdimensions given for clay bricks in Clause 4.2.1-1.

4.2.3 Classification of Clay Masonry Units

1 Units shall be classified as follows:









QCS 2010

(a) non-load-bearing blocks(b) blocks produced for use in non-load-bearing walls(c) load-bearing blocks(d) blocks produced for use in load-bearing walls.

4.2.4 Requirements of Clay Masonry Units

1 Clay masonry units shall be of a uniform shape, free from surface cracks which decreaseits properties. Its outer surface shall be serrated to increase the bonding force with themortar. It should be well burnt, of a uniform texture and free from pebbles of lime.

2 The dimensions of the clay masonry blocks for walls to be as given in Table 4.1.

Table 4.1

Dimensions of Clay Masonry Blocks

Nominal Dimensions (mm) Actual Dimensions (mm)

Length Width Height Length Width Height

300 100 200 290 100 190

300 150 200 290 150 190

300 200 200 290 200 190

400 100 200 390 100 190

400 150 200 390 150 190

400 200 200 390 200 190

3 The tolerance in the actual dimensions of the blocks shall be ±4 %, provided that thedifference between the largest actual dimension and the smallest one in the sameconsignment does not exceed 5 % as shown in Table 4.2.

Table 4.2

Dimensional tolerance

Dimension Size

(mm)

Permissible size

(mm)

Permissible difference betweenlargest actual size and smallest

one in one (consignment)

Largest Smallest

Length 390 406 375 20

290 302 278 15

Width 200 208 192 10

150 156 144 7.5

Height 190 198 182 10

4 Adjacent faces of the units are to be at right angles, and the tolerance of the squareness notto exceed 2 mm for each 100 mm length.

5 The faces should have a plain surface, and the tolerance not to exceed 5 mm from thestraight line.

6 Water absorption of the units shall not exceed 25 % by weight for the individual block and 20% by weight for the average of tested blocks.





QCS 2010

7 The compressive strength of the units, calculated for the total area including holes shall notto be less than the limits shown in Table 4.3.

Table 4.3

Compressive Strength

Class of Block Minimum Value for CompressiveStrength of One Block

Minimum Average of theCompressive Strength

N/mm² (kg/cm²) N/mm² (kg/cm²)

Class 6 6 (60) 7.5 (75)

Class 12 12 (120) 15 (150)

4.2.5 Marking of Clay Blocks

1 Every clay block is to be marked with the name of the manufacturer and/or his registeredmark.

2 The class of block should be shown on every load-bearing block.

4.2.6 Testing of Clay Blocks

1 The following tests are to be carried out on the representative sample taken according toClause 4.2.6-3 of this Part:

(a) appearance(b) dimensions(c) compressive strength(d) water absorption (optional)

2 Appearance and dimension tests are to be carried out on the same units that are to betested for compressive strength and water adsorption. Appearance and dimension tests are

to be carried out before the other referenced tests.

3 A representative sample is to be taken from the consignment not exceeding 15,000 blocksas shown in Table 4.4. As for consignments exceeding that number, one excess block is tobe taken for each 1,000 additional blocks. The sample is to be taken at random duringloading or unloading by dividing the consignment into a convenient number of real orimaginary sections. From each section, a corresponding number of units are to be taken,provided that the total number of samples units is equal as shown in Table 4.4.

Table 4.4

Sample Sizes

Number of units in consignment Number of units for each test

Appearance and size measurements (mandatory)

Compressive strength

(mandatory)

Water absorption

(optional)

5,000 or less 5 3

More than 5,000 and up to 10,000 10 5

More than 10,000 and up to15,000

15 10

4 The methods of test for clay bricks shall be in accordance with the relevant provisions of EN771-1.





QCS 2010

4.2.7 Criteria of Technical Conformity of Clay Blocks

1 The consignment is to be accompanied with a certificate indicating its conformity with all therequirements of this standard.

2 The consignment is to be considered complying with this standard if the representativesample passes all the mandatory tests mentioned in this standard.

3 Compressive test : the consignment will be considered complying with this standard if thefollowing two conditions are fulfilled:

(a) each of the tested blocks meets the minimum limit of compressive strength mentionedin this standard

(b) the tested blocks meet the minimum limit of the average compressive strengthmentioned in this standard.

4 Water absorption : the consignment is to be considered complying with this standard if thefollowing two conditions are fulfilled:

(a) each tested block should meet the minimum limit of water absorption mentioned in thisstandard

(ii) the average water absorption for the tested blocks will meet the minimum limit of the

average water absorption mentioned in this standard.

5 If the tested units do not comply with the requirements of the appearance, dimension and/orabsorption tests, other units may be taken for testing. If these units do not pass the test(s),the consignment is to be considered non-complying with this standard.

4.3 CALCIUM SILICATE BRICKS


1 Calcium silicate bricks are to conform to the requirements of EN 771-2.

2 The brick is to be constructed of sand consisting mainly of quartz or uncrushed siliceousgravel or crushed siliceous gravel or crushed rock or a combination of such materials.

3 Suitable pigments may be mixed into the constituents to produced bricks of the requiredcolour.

4.4 CONCRETE MASONRY UNITS

4.4.1 Concrete Blocks

1 Blocks to be made with ordinary Portland cement unless used below ground floor at naturalslab level in which case sulphate resisting cement is to be used.

2 All blocks are to be manufactured, supplied and tested in accordance with

BS EN 771-3and BS 6073-2.

3 Recycled Aggregates RA and Recycled Concrete Aggregates RCA could be used inconcrete blocks. Its proportion shall be not more than a mass fraction of 20% of coarse

aggregate and according to BS 8500-2 sec 6.2.2.4 Recycled Aggregates RA and Recycled Concrete Aggregates RCA can be used up to 100%

of coarse aggregates, and if applicable then ACI 555 requirements shall be applied.

5 The use of blocks shall comply with Table 4.5. The minimum compressive strength of theaverage of 10 blocks shall be as given in Table 4.5. The associated mortar requirements foruse with different applications for blocks is also provided in Table 4.5. Details of mixes forthe class of mortar specified is provided in Part 2 of this Section.





QCS 2010

Table 4.5

Compressive Strength

Classification Minimum CompressiveStrength (N/mm

2)

Uses for which Blocks are Suitable Class of Mortar

Classes Averageof 10

Blocks

LowestIndividual

Block

1 7.0 5.6 External non-load bearing walls M6

2 10.4 8.3 Load bearing walls M6

3 17.4 14 Load bearing walls below ground M12

4 14.0

11.2

Soakaways and manholes M12

5

4.0 3.6 Internal non-load bearing walls M6

5 4.0 3.6 Roof Block M4

5 4.0

3.6

Protective skins to foundations M6

6 Manufacturer should label or clearly define the classification or the uses of the blocks infactory.

7 Consultant or contractor should also mention the classification or the uses of the blocks inrequest sheet when the samples submit for testing in laboratory.

8 The volume of the cavities in the block shall not exceed 50 % of the gross volume of theblock. The overall dimensions and wall and web thicknesses shall comply with Table 4.6.

Table 4.6

Block Dimensions and Wall and Web Thicknesses

Coordinating (nominal)size (mm)

Work size (mm)Minimum Thickness (mm)

Wall Web

400 x 200 x 100 390 x 190 x 100 19 19

400 x 200 x 150 390 x 190 x 150 25 25

400 x 200 x 200 390 x 190 x 200 32 30

Notes:

(a) Co-ordinating size is the size of the space allocated to the block including the joints and tolerances.

(b) Work size is the actual size for manufacture within the tolerances specified.

9 Subject to the tolerances specified in Table 4.7 and to any requirement for blocks withspecial faces, all surfaces should be flat and rectangular and adjacent surfaces are to be atright angles to one another with clearly defined undamaged arises.





QCS 2010

Table 4.7

Block Tolerances

Dimensions Work Size of Block

Length + 3 mm to - 5 mmHeight + 3 mm to - 5 mm

Thickness 2 mm for any measurement

1.5 mm for the average of 7 measurements in any one block.

10 Unless otherwise specified, all block faces are to provide a satisfactory bond for mortar,plastering or rendering.

11 Each block manufactured from sulphate resisting cement is to be colour coded with anidentifying mark.

12 All connections between masonry walls or partitions and concrete columns or walls shall be

made using propriety stainless steel ties secured to stainless steel fixing channelsembedded in the concrete.

13 Full Water Absorption:

The average water absorption of the tested sample shall not exceed 5% and no individualblock shall have a water absorption greater than 5.5% (in accordance with CML Method 9-97).

14 Water absorption by capillarity method:

The manufacturer shall declare in g/m²s the maximum water absorption coefficient due tocapillarity action of the exposed face of the unit.(according to EN 771-3:2003 )

4.4.2 Manufacture of Concrete Blocks

1 Blocks are to be manufactured in a vibrated/pressure block making machine using cementand aggregate in the proportions required to produce the minimum strengths given in Table4.5.

2 The design of the cavities and webs in hollow blocks is to be submitted to the Engineer forapproval before production commences.

3 The materials to be mixed in a mechanical mixer and placed in the block-making machine inlayers not exceeding 100 mm, each layer being thoroughly vibrated and compacted beforethe addition of the next.

4 Immediately after manufacture the blocks are to be stacked on clean, level, non-absorbentpallets in honeycomb fashion. The pallets are to be marked with the date of production (inEnglish and Arabic) and stored in a level curing and stacking area in such a manner that one

day’s production is separated from the next.

5 Blocks manufactured from mobile machines are to be cast on to a clean concretehardstanding. Each day’s production shall be easily identifiable and kept separate from thenext.

6 All blocks, however manufactured, are to be immediately protected from the effects of thesun and wind by suitable moisture retaining coverings.

4.4.3 Block Dimensions

1 Block dimensions are to be measured in accordance with BS EN 772-2.

2 Blocks not exceeding 75 mm thick and blocks for use in the ground are to be solid unlessotherwise directed. All other blockwork is to be hollow.





QCS 2010

4.4.4 Precast Concrete Bricks

1 Precast concrete bricks are to conform to the requirements of BS 6073-2.

2 Precast concrete bricks are to be manufactured by compacting concrete under high pressureinto a mould.

3 The pressure employed is to be such that a high initial strength is achieved, enabling thebrick to be removed immediately, by extrusion, from the mould.

4 The cement used should be rapid hardening Portland cement and conform to therequirements Part 3 of Section 5.

5 The aggregate used to be sand or manufactured sand.

4.5 GLASS UNITS


1 Glazing units shall incorporate expansion-contraction thermal foam tape, sealants, flashings,and other items necessary for complete installation.

4.5.2 Submittals

1 The Contractor shall submit assembly instructions and installation drawings as required toindicate methods on construction, location and spacing of anchorage, joinery, finishes, sizes,shape, thickness of all materials and relationship to the adjoining work.

4.5.3 Material Storage and Handling

1 Material shall be stored in a dry place, off the ground, where temperature will not exceed 32ºC handle material to prevent damage to finished surfaces. Do not install scratched ordamaged components.

2 After installation, finished surfaces shall be protected from damage caused by ensuing work.

4.5.4 Laying

1 The Contractor shall verify all applicable field dimensions and adjust as necessary toaccommodate the glazed wall.

2 The glass block grid system for the wall shall be assembled and sealed in accordance withinstructions furnished by the manufacturer.

3 The assembled glass block grid system frame shall be placed into a properly prepared and

sized rough opening and adjust until plumb and level. The grid system shall be screwed ornailed into place utilising all predrilled holes in the nailing flange.





QCS 2010

4 A foam tape gasket shall be adhered to each of the glass blocks according to instructionsfurnished by manufacturer of the glass block grid system. The glass blocks shall be carefullyinserted into the grid system from the exterior side of the wall so that each block is pressedagainst the T-Bar and the foam tape does not roll back.

5 Sealant to completely fill the channel shall be applied around each glass block and wipeflush with the surface. The sealant shall be applied to the exterior frame corners according

to instruction furnished by the grid system manufacturer.

6 All exposed surfaces of the glass block grid system shall be cleaned with a clean, soft clothand mild hand soap using gentle rubbing action. Abrasive or solvent-type cleaner, detergentsor paint removers shall not be used.

7 All labels shall be removed from the glass blocks and cleaned with a soft cloth and water.

4.6 GYPSUM UNITS


1 Blocks for claustra walls are to be manufactured and built generally in accordance with thepreceding clauses for blockwork, except where otherwise noted below.

2 Blocks may be constructed of either(a) white gypsum plaster(b) concrete(c) white concrete using white Portland cement and white aggregates, as described in the

relevant provisions of Section 5, Concrete, or as described in the ProjectDocumentation.

3 All blocks are to be finished with a fine finish to an approved ornamental pattern and are tobe 100 m thick unless otherwise noted with slots in ends of blocks to receive reinforcement.

4 Claustra walls should be built with vertical straight joints reinforced with 12 mm mild steelreinforcing bars vertically at each straight joint pinned to structure at each end andsurrounded solid with mortar.

5 Blocks are to be bedded in a mixture of white cement and sand (1:4) and struck pointed toapproval.

4.7 STONE WORK


1 Stone work includes rough cut stone, marble, limestone, granite.

2 Stone work shall be executed by an approved specialist sub-Contractor

3 Stone should be sound and free from defects which would impair strength, durability orappearance. Each species of stone is to be provided from a single quarry. Quarries andfabrication plants should be available for inspection by the Engineer.

4 All stone to be of soundness (hardness and density), texture, graining colour, tone and rangematching the Engineer’s sample.

5 Dielectric separator: Bituminous paint is to be used in accordance with the manufacturer’sinstructions and shall be approved by the Engineer.

6 Cushions: Clear plastic or neoprene, 25 by 50 mm, thickness as required.

4.7.2 Anchorage Devices

1 Anchors, dowels, cramps, plug anchors, angles, relieving anchors: Fabricated of stainlesssteel or non ferrous metal (e.g. bronze) complying with thickness as required to systemimposed loads but not less than 5 mm.

2 Embedded items shall be of malleable iron castings or steel fabrications, thickness asrequired to sustain imposed loads but not less than 5 mm thick products to be stainless steelor non-ferrous. Devices embedded in concrete or masonry include the following:

(a) edge inserts with tee-shaped wedge-action slot, with askew head bolt, washer and nut





QCS 2010

(b) dovetail anchor slots of size to receive specified anchor, filled with waterproof filler andopen face sealed

(c) adjustable insert with square nut slinging in integral track.

3 Reinforcing mesh used for anchorage shall be stainless steel.

4.7.3 Mortar

1 Mortar shall comply with the relevant provisions of Part 2 of this Section. The cement usedfor stone work mortar shall be white Portland cement. The Class of mortar

2 Mortar for setting stone flooring, steps and treads shall be Class M7 mortar. The grout shallincorporate a waterproofing additive for wet area flooring.

3 Mortar for setting all other stone shall be Class M3 mortar. The mortar shall incorporate awaterproofing additive for wet areas and exterior stone. The mortar shall incorporate ashrinkage-reducing accelerator diluted with water in the ratio as recommended by themanufacturer.

4 Pointing mortar: shall be Class M5 mortar with a mineral colouring admixture as required tomatch the stone. The mortar shall incorporate a waterproof additive for exterior and wet areapointing.

4.7.4 Fabrication

1 The Contractor shall accurately cut, dress, drill, fit and finish stonework to shapes anddimension shown on the approved Shop Drawings. Exposed plane surfaces shall be madetrue in line and exposed curved surfaces true in radius. The thickness of the stone shown isthe minimum thickness.

2 For wall facings, the Contractor shall do the following:

(a) cut exposed external corners of stone as shown(b) ease exposed external edges where shown(c) cut all other joints and edges square and at right angles to face, and with backs

parallel to face

(d) make arises straight, sharp, true and continuous at joints(e) cut curved stone panels true to radius as shown to produce an even, flush curvedsurface.

4.7.5 Installation

1 Dovetail anchor slots, wedge type inserts, and other items requiring building in to concrete ormasonry work shall be furnished in sufficient time so as not to delay the progress of thework. Tie inserts shall be wired into reinforcing to prevent displacement. No forced entryanchorage device will be allowed.

2 Stone shall be set in accordance with the approved Shop Drawings, level, plumb, square andtrue with uniform joints, accurately aligned with grain running in the direction as approved bythe Engineer unless otherwise stated elsewhere in the Project Documentation. The workshall match mock-ups.

3 Dowels, anchors and ties in shall be provided in sufficient quantity to eliminate “rattle” orloose pieces and to ensure a rigid installation. The extent of the anchorage and installationdetails shown are intended to indicate minimum requirements. In general, a minimum of oneanchor per 0.18 m

2 is required, with additional anchorage provided where necessitated by

the size, thickness and setting or shape.

4 Steel backup support shall be provided for the stone work where shown on the ProjectDrawings and as required to provide rigid installation. Steel support framing shall beanchored securely to the building structure.

4.7.6 Wall Cladding

1 Relieving angles shall be set as required for the proper support of stone. Before setting, theContractor shall clean the stones and the backing. The stone shall be saturated with waterbefore setting in mortar in order to prevent total absorption of moisture from the mortar.





QCS 2010

2 Stone shall be set with two cushions per stone in every horizontal joint, extending full depthof the stone and to within the dimension from the face as shown. Secure with anchors,dowels, and cramps of approved construction, as required for a rigid and secure installation.Fill anchorage holes with accelerated setting mortar. Rigidly secure strap anchors to thebacking.

3 Flashing materials shall be repaired to their original condition where they have been

punctured by anchorage or damaged during setting.

4 Cavities shall be kept behind the facing free of mortar or other foreign material.

5 Fill and seal joints as indicated in the Project Documentation.

4.7.7 Paving and Flooring

1 The following shall be performed by the Contractor when laying paving and flooring:

(a) place reinforcing mesh in the setting bed(b) tamp the stone into the setting bed with mallet until firmly bedded to the proper level(c) remove stone, cover the back of the stone with wet cement and return to position on

the setting bed; before applying the wet cement, wet the back of the stone to preventmajor absorption of moisture from the cement

(d) use cushions and spacers to maintain uniform jointing and setting.

2 Joints shall be grouted with water and neat cement by buttering the edges of the stones asthey are laid. Surplus joint cement cleaned from face of the stone immediately.

3 Where grinding is required to completely align and level joints, permit a minimum of six daysof setting time to elapse before commencing grinding. Perform grinding by wet abrasion, in amanner as to retain the finish, to match the balance of stone paving, and so as to be free ofdepressions and grind marks. The Contractor shall exercise care to avoid damage to orsoiling of adjacent work.

4.7.8 Erection Tolerances

1 The following maximum non-cumulative erection tolerances shall be complied with:

(a) variation from plumb +/- 3 mm in storey height(b) variation from level +/- 3 mm in any bay(c) variation in location +/- 6 mm in any bay(d) edge alignment 1.5 mm

4.7.9 Submittals

1 Submittals shall be made in accordance with the relevant provisions of Section 1, Generaland the following Clauses.

2 Shop Drawings: The Contractor shall submit shop drawings of the stonework showing indetail the layout, jointing, anchors and dowels, dimensions, sizes and locations of cut-outs,adjoining work, etc. Each piece on the Shop Drawings is to correspond to the identificationnumber on the back of each stone. The Contractor shall co-ordinate all components which

are specified elsewhere (flashing, insulation) which comprise the system into this submittal.Shop Drawings shall be co-ordinated with all related trades.

3 Samples: The Contractor shall submit to the Engineer 600 x 600 mm sample panels withcross-joints to show the sealant materials of each type and finish of stone required. Thesamples shall show the full range of colour and texture expected in the finished work. Inaddition the Contractor shall submit one (1) full size sample of each type and finish, falling inthe average colour and texture range. The Engineer’s review and approval of the sample isto be for colour, texture and pattern only. Compliance with all other requirements is theexclusive responsibility of the Contractor.

4.7.10 Visual Mock-ups

1 Following the approval of the samples, the Contractor shall construct mock-ups for approval

by the Engineer prior to installation. Mock-ups to be provided shall be as follows:





QCS 2010

(a) wall facing: assembled to simulate the final condition, direction of graining, andindicating joint conditions, use of spacers, shims, anchorage, relieving angles,supports, and all other features of the final work

(b) flooring: samples of flooring/skirting, etc, of each type of stone work specified is toconsist of a full pattern and be complete with all anchors, bedding, jointing, sealers,etc., in accordance with approved shop drawings

(c) provide mock-up for any other stonework as shown on the drawings and as requiredby the Engineer.

4.8 CAST STONE


1 The requirements for manufactured stone for vertical applications and for trim, includingcopings and sills shall comply with the relevant provisions of BS 1217 or ASTM C1364 andreconstructed masonry shall comply with the relevant provisions of BS EN 771-5.

2 Cast stone work is to be executed by an approved specialist subcontractor.

3 All cast stone is to be sound and free from defects which would impair strength, durability orappearance. Each type of stone is to be supplied from the same quarry. Quarries and

fabrication plants are to be available for inspection by the Engineer.

4 Joint sealing compounds used with stone will conform to Section 24, Part 15.

4.8.2 Submittals

1 Samples: The Contractor shall supply cast stone sample panels, size 200 x 200 x 300 mm,for each colour and finish of stone for approval by the Engineer.

2 Shop Drawings: The Contractor shall provide drawings of cast stone work showinganchorages for the approval of the Engineer.

3 Certificates: The Contractor shall provide certification documentation as necessary,describing in detail testing laboratory facilities and qualifications of its principals and keypersonnel. The Contractor shall also provide certification that the cast stone meets

requirements of the Project Documentation.4.8.3 Product Delivery, Storage and Handling

1 Cast stone shall be cured for a minimum of 30 days before delivery. Each unit is to have thedate of manufacture impressed in the back of the stone.

2 Cast stone shall be stored under waterproof covers on boarding clear of the ground and shallbe protected from handling damage, dirt, stain, water and wind.

4.8.4 Anchorage Devices

1 Coping stones shall be anchored to the masonry with no less than two dowels to each stone.Dowels may be either 8 mm stainless steel pipe 75 mm long or 12 mm diameter stainlesssteel bars 75 mm long.

2 Course stones shall be anchored to the backing with one metal anchor for each 600 mm inlength. Each stone shall have not less than two anchors. Anchors are to be stainless steel 4mm x 30 mm with the end in the stone turned down 25 mm and other end turned up to 50mm

END OF PART




QCS 2010 Section 13 Part 5 Masonry Laying Page 1

QCS 2010

5. MASONRY LAYING ....................................................................................... 3

5.1 INTRODUCTION ........................................................................................... 3

5.1.1 Scope 3

5.1.2

References 3

5.2 WORKMANSHIP ........................................................................................... 3


5.3 BLOCKWORK ................................................................................................ 3

5.3.1 Setting Out of Blockwork 3

5.3.2 Wetting Blockwork Units 4

5.3.3 Laying of Blockwork 4

5.4 BRICKWORK ................................................................................................. 5

5.4.1 Brickwork Wetting and Brick Wetting Test 5

5.4.2

Brickwork Laying 5

5.5 REINFORCEMENT ........................................................................................ 6


5.5.2 Placing Reinforcing 6

5.5.3 High Lift Grouting of Cavity Walls 7

5.5.4 Low Lift Grouting of Cavity Walls 7

5.5.5 Water Penetration Testing 7

5.6 FAIR FACED BLOCK WALLS ....................................................................... 8


5.7 OPENINGS .................................................................................................... 8


5.8 INTERSECTING WALLS AND PARTITIONS ................................................ 8


5.9 CONNECTIONS BETWEEN WALLS OR PARTITIONS AND COLUMNS ..... 9


5.10 JOINTS BETWEEN PARTITIONS AND FLOOR SOFFITS ........................... 9

5.10.1


5.11 FILLING HOLLOW BLOCK WALLS ............................................................... 9


5.12 CAVITY WALLS ............................................................................................. 9


5.13 SERVICES ................................................................................................... 10


5.13.2 Fixings 10





QCS 2010

5.14 DAMP-PROOF COURSES .......................................................................... 10

5.14.1 General Description 10

5.15 PROTECTION OF FINISHED WALLING ..................................................... 11

5.15.1 General Description 11





QCS 2010

5. MASONRY LAYING

5.1 INTRODUCTION

5.1.1 Scope

1 This Part specifies workmanship and setting out of masonry works.


This SectionPart 2 Mortar and groutPart 4 Unit Masonry

Section 6 Concrete

5.1.2 References

1 The following standards are referred to in this Part:BS 743 Materials for Damp-Proof CoursesBS 6398:1983 Specification for bitumen damp-proof courses for masonryBS 6515:1984 Specification for polyethylene damp-proof courses for masonryBS 8215:1991 Code of practice for design and installation of damp-proof courses in

masonry construction

5.2 WORKMANSHIP


1 Work is to be performed by experienced workers under the direction of a qualified supervisor

who is fully aware of the Project requirements. Final work is to be equal to any samplepanels submitted to, and approved by, the Engineer.

5.3 BLOCKWORK

5.3.1 Setting Out of Blockwork

1 All blockwork is to be fully set out before laying commences to ensure:

(a) correct bonding over all lengths of wall particularly at openings and piers(b) minimum cutting(c) compliance with Table 5.1

2 The average thickness of both vertical and horizontal mortar joints is to be 10 mm exclusive

of any key in the joint surfaces of the unit.





QCS 2010

Table 5.1

Setting Out of Blockwork

Item of Construction Type of DimensionsPermissible Deviation

(mm)Space between walls At floor

At Soffit

20

30

Size and shape of wallelements

Height up to 3,000 mm

Straightness in 5,000 mm

Verticality up to 2,000 mm

Level of bed joints in 3,000 mm

40

8

15

15

Walls Position in plan of any point orspecified face in relation to nearest

grid line on the same level

15

Door, window and otheropenings

Position in elevation from designposition

Level of sill or soffit for each 1,000mm of width

with maximum of

Verticality of any point for each1,000 mm of height

with maximum of

15

5

15

5

15

5.3.2 Wetting Blockwork Units

1 All blocks are to be adequately wetted with water before they are laid and the tops of wallsleft off from the previous day’s work are to be similarly wetted before the new workcommences.

5.3.3 Laying of Blockwork

1 Block walls are to be built from undamaged blocks in stretcher bond unless otherwisespecified.

2 All bed and vertical joints are to be spread with mortar to ensure complete and solid bedding

and grouting through the full thickness of the wall. All keys in jointed surfaces must becompletely filled.

3 Mortar extending into the cavities of hollow blocks which are to be reinforced and filled shallbe removed.

4 Each block is to be adjusted to its final position in the wall whilst the mortar is still plastic. Any block which is moved after the mortar has stiffened shall be removed and relaid withfresh mortar.

5 Half blocks and special blocks are to be used as required to ensure correct bonding.

6 All perpends, quoins and joints are to be kept true and square, other angles are to be

plumbed and bed joints levelled as the work proceeds.





QCS 2010

7 The work is to be carried out course by course not leaving any part more than 800 mm lowerthan another. Work, which is left at different levels, is to be racked (stepped) back to theapproval of the Engineer.

8 In cavity wall construction both leaves are to be carried up together, not leaving any leafmore than 400 mm below the other.

9 Partitions shall be 100 mm thick unless otherwise noted. Partitions having lavatories orother plumbing fixtures secured to them back-to-back (or approximately so) are to be aminimum of 150 mm thick. Solid concrete masonry units shall be built in where full unitscannot be used or where needed for the fixing of accessories. Bells or hubs of pipes must becompletely enclosed.

10 Reinforced masonry partitions are to fully extend to the underside of slabs.

11 When pipes or conduits or both occur in plastered partitions, at least one web of the hollowmasonry units must be retained.

12 When new masonry partitions start on existing floors, the existing floor finish material is to be

cut down to the concrete surface. New masonry partitions are not to abut any existingplastered surfaces, except suspended ceilings.

5.4 BRICKWORK

5.4.1 Brickwork Wetting and Brick Wetting Test

1 Bricks shall be laid dry unless the following test indicates the need for wetting:

(a) draw a 30 mm circle with wax crayon on bed surface of dry brick. Using a medicinedropper, place 20 drops of water inside the circle and measure the time required forabsorption of the water

(b) if water is absorbed in less than 1½ minutes the brick must be wetted before being

laid.

2 Bricks are to have no visible moisture when laid.

5.4.2 Brickwork Laying

1 Unless otherwise specified elsewhere in the Project Documentation, bricks are to be laid in arunning bond with each course of masonry bonded at the corners. The bond of facing bricksin existing buildings shall be matched. Before starting work, facing bricks shall be laid on thefoundation wall and the bond adjusted as needed for openings, angles, corners, etc.Exposed brickwork joints are to be symmetrical about centre lines of openings. No bricksmaller than a half-brick shall be used at any angle, corner, break, or jamb. The bond patternshall be maintained plumb throughout. Jumping of the bond is prohibited. Brickwork shall be

anchored to concrete columns, beams and walls, to steel stud construction and to masonrybackup with ties and anchors in accordance with the relevant provisions of BS 5628.

2 Bricks shall be laid in a full bed of mortar. The mortar shall be spread over a few bricks at atime and shall not be furrowed. The mortar bed shall be slightly levelled to incline towardsthe cavity. The brick shall be placed before the mortar has had chance to stiffen. Head jointsin stretcher courses are to be completely filled with mortar. Bricks shall be pushed into placeso that the mortar oozes out at the top of the joints.

3 Before connecting new masonry with masonry previously laid masonry, loose bricks ormortar shall be removed, and the previously laid masonry shall be cleaned and wetted. Newwork is to be toothed into unfinished work.

4 Brick headers are not to project into the grout space.





QCS 2010

5 Cleaning holes are to be left in double cavity walls during construction by omitting units atthe base of one side of the wall. In general, clean-out holes are to be provided at eachlocation of vertical reinforcement.

6 Cavities shall be kept clean of mortar and debris. The cavity shall be cleaned every dayusing a high pressure jet stream of water, compressed air, industrial vacuum, or by laying

wood strips on the metal ties as the wall is built. If wood strips are used, lift strips with wiresor heavy string as the wall progresses and before placing each succeeding course of wallties.

7 Exterior walls shall be built with 100 mm of facing brick, backed-up with inner leaf of brick orconcrete masonry units. Solid brick jambs shall be constructed not less than 200 mm wideat exterior wall openings and at recesses.

8 Joints are not to be tooled until mortar has stiffened enough to retain a thumb print when thethumb is pressed against the mortar, however, mortar is to be soft enough to be compressedinto joints. Joints in exterior face brick work shall be finished with a jointing tool to producesmooth, watertight concave joints. Exposed interior joints in finished work shall be tooled toa concave profile.

5.5 REINFORCEMENT


1 Expanded stainless steel mesh joint reinforcement, if specified, will be embedded in thehorizontal mortar joints not closer than 20 mm from the external face of the wall and, exceptat movement joints, is to be continuous and lapped at least 75 mm at all passings. Full lap

joints are to be provided at angles.

2 Vertical bar reinforcement is to be properly positioned and secured against displacement.The cavities containing the reinforcement are to be completely and solidly filled with thespecified concrete. The whole surface of the reinforcement is to be in contact with the mortaror concrete. The minimum clear distance between the vertical bars and the block is to be 12mm.

5.5.2 Placing Reinforcing

1 At the time of placement, steel reinforcement is to be free from loose flaky rust, mud, oil, orother coatings that will destroy or reduce the bond.

2 Steel reinforcement is to be in place at the time of grouting. Horizontal reinforcement shall beplaced as the masonry work progresses.

3 The minimum clear distance between reinforcing and masonry units shall be 12mm.

4 The minimum clear distance between parallel bars shall be one bar diameter.

5 Vertical steel reinforcement shall be held in place by centring clips, caging devices, or otherapproved methods.

6 Vertical bars shall be supported near each end, and at intermediate intervals not exceeding80 bar diameters.

7 Horizontal reinforcement shall be set in a full bed of grout.

8 Reinforcement shall be spliced or attached to dowels by placing in contact and wiringtogether.

9 Splices shall be staggered in adjacent reinforcing bars. Reinforcing bars shall be lapped atsplices at a minimum of 40 bar diameters.





QCS 2010

5.5.3 High Lift Grouting of Cavity Walls

1 Grout shall be placed by hand bucket, concrete hopper, or grout pump. Each lift of groutshall be consolidated after free water has disappeared but before plasticity is lost.

2 When placing grout by the high lift method, the Contractor shall:

(a) not pour grout until the masonry wall has properly cured for a minimum of 72 hours(b) close cleaning holes with masonry units(c) place grout in one continuous operation (grouting of any section of a wall between

control barriers is to be completed in one day with no interruptions greater than onehour)

(b) provide vertical solid masonry dams across the grout space for the full height of thewall at intervals of not more than 9 m

3 High lift grouting of double cavity walls should be undertaken in a single, continuous pour ofgrout to the top of the wall in 1 m layers or lifts in the same working day, with a minimumwaiting period of 10 minutes between each 1 metre layer or lift. Each layer or lift of grout isto be vibrated. The vibrator is to be extended 300 mm to 450 mm into the preceding lift toclose any shrinkage cracks or separation from the masonry units.

4 Grout for cavities of double cavity walls less than 50 mm wide should not be poured from aheight exceeding 300 mm.

5.5.4 Low Lift Grouting of Cavity Walls

1 Grout shall be placed by hand bucket, concrete hopper, or grout pump. Each lift of groutshall be consolidated after free water has disappeared but before plasticity is lost.

2 Double cavity masonry walls are to be constructed and grouted in lifts not to exceed 200mm. Slushing with mortar will not be permitted.

3 The grout space shall be kept clean from mortar droppings and clean the space beforeplacing the grout.

4 All grout is to be puddled with a grout stick during and immediately after placing.

5 The cores of concrete masonry units containing reinforcing bars shall be grouted as themasonry work progresses. Slushing with mortar will not be permitted.

5.5.5 Water Penetration Testing

1 Seven days before plastering or painting, the Contractor shall test exterior masonry walls forwater penetration. The number and location of tests shall be as stated in the ProjectDocumentation or as directed by the Engineer.

2 Water shall be directed at masonry for a period of one hour at a time when wind velocity isless than five miles per hour.

3 The areas showing moisture on the inside of the walls shall be corrected and re-tested toinsure that moisture penetration has been stopped.

4 Unless otherwise instructed, testing shall take place in the presence of the Engineer.





QCS 2010

5.6 FAIR FACED BLOCK WALLS


1 Fair faced block walls and walls built of facing blocks are to be constructed generally asClause 5.3.3 with particular care being taken to ensure:

(a) the specified bonding or joint pattern is consistent(b) the perpends are truly plumb for the full height(c) the blocks used are of the same texture and appearance to avoid a patchy effect(d) the colour of the mortar is consistent.

2 When a block has been placed in the wall, the extruded mortar is to be struck off flush, extracare being taken to avoid smearing the mortar on the face of the block.

3 Joints are to be left to stiffen slightly (thumb print hard) and then be firmly compacted with a jointing tool to the required profiles. The tooling of wet mortar will not be permitted.

4 If mortar droppings have struck to the blocks it must be allowed to dry and the surplus

removed by a trowel. The remaining residue shall be cleaned by rubbing with a small pieceof block and subsequent brushing down.

5 Where the cutting of blocks in fair face work is unavoidable, this should be done using amechanical saw.

6 The cutting of facing blocks will only be permitted where this can be achieved without avisible alteration to the facing pattern.

5.7 OPENINGS


1 Openings are to be square and the jambs, vertical and formed with the uncut faces of theblocks.

2 If door and window frames are to be built-in the requirements of Clause 5.3.4 of Section 18shall be complied with and the fixing cramps built-in solid in the mortar joints.

3 The jamb walling is to be built up against the frame all round as the work proceeds.

5.8 INTERSECTING WALLS AND PARTITIONS


1 Walls and partitions are to be bonded or tied to one another at junctions, unless movement joints are indicated.

2 If ties are used they should consist of 3 x 20 mm stainless or galvanized steel as directed bythe Engineer fully embedded in the horizontal mortar joints at vertical spacings notexceeding 600 mm.

3 The ends of the ties are to project a minimum of 75 mm into each wall or partition.





QCS 2010

5.9 CONNECTIONS BETWEEN WALLS OR PARTITIONS AND COLUMNS


1 All connections between block walls or partitions and concrete or steel columns are to bereinforced at maximum 400 mm centres by means of stainless steel or zinc coated expanded

metal as directed by the Engineer or approved proprietary ties shot fired to the column andbuilt into and fully embedded in the mortar joints of the block walls or partitions.

2 Stainless steel or expanded metal ties as directed by the Engineer are to be a width that willallow 20 mm clearances from each face of the wall or partition and be embedded for aminimum distance of 200 mm in the mortar joint.

5.10 JOINTS BETWEEN PARTITIONS AND FLOOR SOFFITS


1 Non-load bearing internal walls and partitions shall be built-up to leave a 20 mm jointbetween the top of the wall or partition and the soffit of the slab.

2 After the walling has thoroughly dried out and after the expected deflection in the slab due todead load has taken place, the joint is to be filled solid with a Class M7 mortar in accordancewith the relevant provisions of Part 2 of this Section.

3 Where concrete slabs are supported on blockwork, a layer of polythene sheet is to beprovided between the top of the wall and the slab for the full width of the wall.

5.11 FILLING HOLLOW BLOCK WALLS


1 In the following situations, the cavities of hollow block walls are to be filled solid with eitherClass M7 mortar in accordance with the relevant provisions of Part 2 of this Section orconcrete Grade C15:

(a) jambs of all openings(b) ends, angles and junctions of walls and partitions(c) junctions of walls and partitions with columns(d) at sills(e) at tops of partitions, if so specified(f) to provide a solid fixing for false ceiling perimeters

2 The filling to courses is to be supported on a strip of expanded metal lathing embedded inthe joint below.

3 Walls which are to be filled solid are to be built up in lifts not exceeding 1,200 mm and befilled after allowing a minimum period of 24 hours to elapse to enable the mortar to harden.The initial compaction of the concrete is to be carried out by hand using a 25 x 50 mmwooden rod or by vibrator. The final compaction shall take place 10-15 minutes after initialcompaction.

5.12 CAVITY WALLS


1 Cavity walls are to consist of two walls separated by a minimum space of 50 mm andbonded together with stainless steel or approved other cavity wall ties.





QCS 2010

2 The air space between the walls is to be kept clear and clean of mortar droppings by the useof laths drawn up the cavity as the work proceeds or by other approved methods.

3 Any mortar which inadvertently falls on wall ties is to be removed.

4 Wall ties are to be spaced at the intervals given in the Table 5.2 unless otherwise indicated

elsewhere in the Project Documentation. Additional ties are to be provided in each coursewithin 250 mm of openings or at end wall situations and on each side of movement joints.

Table 5.2

Spacing of Wall Ties in Cavity Walls

Cavity Width(mm)

Maximum Horizontal Spacing(mm)

Maximum Vertical Spacing(mm)

50 - 75 1,000 400

75 - 100 800 400

100-150 500 400

Notes:

(a) The spacing of ties may be varied providing that the number per unit area is maintained.(b) The Table is applicable to cavity walls constructed of two blockwork skins.

5.13 SERVICES


1 Where walls are constructed of hollow blocks, the mechanical and electrical services are tobe run in the cavities of the blocks wherever possible. No services are to run within the cavityof a cavity wall.

2 Where chases have to be cut, suitable power tools, as approved by the Engineer, are to beused.

5.13.2 Fixings

1 Where fixing blocks, anchors, accessories, wall ties, etc., are specified they are to be builtinto the walls or partitions and solidly bedded in mortar.

2 Fixings which are not built-in are to be drilled or shot fired to the blockwork.

3 Expanded bolt fixings are only to be drilled into solid blocks or blocks having their cavitiesfilled solid.

5.14 DAMP-PROOF COURSES

5.14.1 General Description

1 Damp-proof courses shall comply with the relevant provisions of BS 743 or one of the otherreferences mentioned in 5.1.2.

2 Damp-proof courses are to extend through the full thickness of the wall, including pointing,applied rendering or any other facing material.





3 The mortar bed upon which the damp-proof course is to be laid is to be even and free fromprojections liable to cause damage to the damp proof course.

4 Where the damp-proof course is situated in a hollow block wall, the blocks are to be filledsolid in the course below the damp proof course.

5 All damp-proof courses are to be solidly bedded in mortar.

6 Joints of all damp-proof courses shall be lapped a minimum of 100 mm at all passings andsealed.

5.15 PROTECTION OF FINISHED WALLING

5.15.1 General Description

1 All newly or partially built walls are to be protected against drying out too rapidly in the sun’sheat by covering with hessian or other approved material which is to be kept wet for aminimum of 3 days.

END OF PART

section 13 (masonry) - qcs 2010

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