trade specification for ceramic wall/floor tiler...ceramic floor tiles (customer upgrade) 4.14 the...

Trade Specification for Ceramic Wall /Floor Tiler October 2019

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TRADE SPECIFICATION FOR CERAMIC WALL/FLOOR TILER

INTRODUCTION This trade specification must be read in conjunction with th Bovis Homes’ Contract Conditions, all drawings, specifications, any planning or environmental requirements and relevant sections of NHBC Standards. 1.0 GENERAL REQUIREMENTS

1.1 As a minimum requirement, all operatives must hold a current CSCS card

applicable to their trade. Supervisors must hold a current CSCS Gold Card or CITB SSSTS certificate. All trades totalling three or more operatives on site must have an on-site trade supervisor (SSSTS or gold card). This person can be a working supervisor.

1.2 Contractors shall provide evidence that their operatives have received suitable

training for any plant or equipment they will be operating/using, including proprietary access systems where applicable. All hand-held power tools will either be battery or 110v powered where practicable and must be maintained in good condition with all guarding/safety features in place. Permission must be sought from the Bovis Homes’ where any tools are required with increased voltage. Contractors are required to carry out 3 monthly PAT testing for all electrical tools on site.

1.3 All operatives and supervisors are required to participate in the Bovis Homes

Health and Safety Induction and Quality Induction Programme before commencing work on site. This will be given by the Site Manager and a signed record maintained.

1.4 The Contractors Supervisor is required to attend and actively participate in Daily

Activity Briefings (DABs) with the Site Manager. Supervisors are required to visually inspect work areas prior to putting operatives to work. Contractors should be made aware of all Standard Operating Procedure’s (SOPS) and must comply with the requirements.

1.5 A Trade Self-Certification Checklist must be completed by the Contractor for every

plot and receipt of the same by the Employer is a prerequisite of final payment. 1.6 The Contractor will be required to assist with the completion of the Bovis

Production Quality Plot Log for each plot. 1.7 Any inadequate information must be highlighted to the Employer in writing. It

will be the Contractor’s responsibility to ensure that sufficient information is available to carry out the works to meet all technical, health and safety and programme requirements.


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2.0 FACILITIES PROVIDED BY THE EMPLOYER The following will be provided by the Employer:

2.1

2.2

Shared welfare facilities as per Bovis Homes’ Policy for Health, Safety and Welfare. Fork lift truck/driver assistance on a shared use basis with other trades. No claims for standing time will be entertained. Unless otherwise stated at enquiry, Bovis Homes will supply one fork lift and one driver only under the terms of the Contract.

All other plant, equipment and tools shall be supplied by the Contractor, e.g. 110-volt or

lower power generating plant and fuel, transformers, all power tools, hand tools and consumables, sufficient to meet the requirements of the programme and the progress of the works. All electrical equipment must be PAT tested. Additionally, seasonal hire of task lighting and heating equipment when necessary is the Contractor’s responsibility.

3.0 MATERIALS

All materials are to be supplied by the Contractor. Ceramic tiles, BUTECH adhesives, grout and ancillaries are to be obtained from PORCELANOSA as specified in the Porcelanosa Fixing Specification attached and are available at preferential rates for Bovis Homes Contracts. Refer to the current range issued as part of specific tender instructions for the development.

4.0 SCOPE OF WORKS

The following section provides an overall description of works to be undertaken by your trade and, as such, highlights extracts of standards, workmanship and practice for your attention, it cannot describe all of the detailed requirements of British Standards, EU Standards, NHBC Standards, manufacturer’s instructions, industry trade best practice and other legislative requirements which will be deemed to apply to your trade. All works shall be carried out in accordance with BS 5385 Wall and Floor Tiling Part 1: 2009. Refer to General Specification for extent of tiling to walls and floors. Porcelanosa recommended fixing specification ref. B7014/2 is attached. You will note that purely representative wall tile ranges have been included in the descriptions. This specification should be followed without exception. Adequate dust control measures to be provided when machine cutting tiles, to include extraction/FFP3 with face fit testing. Please note the following specific requirements which are highlighted for ease of reference:

4.1 The existing backgrounds and bases are to be prepared as per Clause 300. 4.2 All plasterboard walls are to be primed as per Clause 462.


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4.3

All chipboard floors to be overlaid with 6mm WBP plywood screw fixed at 200mm centres using counter sunk 25mm screws (by Carpentry Contractor).

4.4

Plywood floors to be primed as per Clause 462a

4.5 All adhesives, primers, grout and other tile ancillaries to be BUTECH products as specified and obtained from Porcelanosa.

4.6

BUTECH waterproof tile adhesive and grout must be used throughout. Suitable adhesive/primer to be used for fixing tiles to any plywood boxing. (Refer to Porcelanosa specification as before described).

4.7 Seal any plywood in shower locations with Unibond solution as extra safeguard

to water penetration. Ensure that a minimum 150mm cut tile is always fixed as first course above shower tray, as Standard Detail Sv 127.

4.8

4.9

Customers or sales department’s choice of tiles to be fixed in each bathroom, en-suite, kitchen and cloakroom as indicated in the General Specification. Please refer to this carefully to ascertain extent of tiling. To facilitate potential future maintenance requirements the Contractor shall ensure that 6no wall tiles from the batch used in each bathroom and ensuite are placed under the bath.

4.10 Proprietary plastic quadrant corner edge trims to be used at all external angles

and stop beads to exposed edges. 4.11 All Silicone Sealant/Mastic will be undertaken by the Mastic Contractor. Tile trim

will be undertaken by the Wall Tiling Contractor. All tiled areas to be polished and cleaned by the Wall Tiling Contractor.

4.12 All cutting and fitting around fittings and fixtures to be included. 4.13 Tiling around fixings (radiator tails, pipework, brackets, etc) must be cut using

circular diamond tipped bits or saws to complete a neat and tight finish. On no account will snapped tiles be accepted.

Ceramic floor tiles (Customer Upgrade)

4.14 The Contractor must ensure that the flooring material is laid on a clean, level,

surface. Unless otherwise stated, floor tiles are to be laid square, i.e. not diagonal pattern. See Clause 4.3 and 4.4

4.15 Include cutting around units, obstructions and perimeters of room. 4.16

4.17

Where applicable, tiles to be laid in all appliance spaces and under the front edge of the kitchen units. On Completion of floor tiling, it is the Contractors responsibility to lay/fit floor protection material supplied by Bovis Homes (see clause 5.1).


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5.0 PROTECTION OF THE WORKS 5.1 The Contractor shall protect all works in accordance with Bovis Homes’ Site

Materials Protection Policy Rev A. 5.2 Protection of worktops, baths, basins and sinks should be applied by others and

should be maintained and reinstated by yourselves as necessary. 5.3 On no account may tilers work inside baths or shower trays without ply

protection board, nor should it be removed to work. 5.4 Damage arising to any other material including sanitaryware, kitchen units and

worktops as a result of your work will be contra charged.

6.0 WASTE MANAGEMENT 6.1 GENERAL 6.1.2 The control of waste is not only a key issue for Bovis Homes but also for

all our Contractors. Together we need to minimise waste production and reduce the expense of disposing of any waste materials that we produce.

6.1.3 We would draw your attention to the section on site tidiness contained in

the Contract Conditions, in particular frequency of clearing and cleaning. All work areas are to be left clean and any waste/rubbish placed into mini skips on a daily basis.

6.1.4 All tile waste, off cuts, etc, to be placed into Green mini skips (Inert

Waste), plastic, cardboard and paper waste should be placed into Orange mini skips (LMW Waste).

6.1.5 The Contractor will be contra charged for waste not disposed of in the

correct manner, including consequential costs


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BUTECH M40 TILING SPECIFICATION

110 . GENERAL WALL TILING TO PLASTERBOARD WALLS

Tiles : PORCELANOSA, VENIS AND CERANCO WALL TILES Size : 200 x 316 x 10mm to 333 x 666 x 10mm Base/Background : Plasterboard / Skimmed Plaster Preparation : General preparation as clause 300. Bedding : BUTECH NOTCHED TROWEL (WALLS) as clause 730 Adhesive : BUTECH BT-2000 N (Plaster and Plasterboard surfaces should

not be primed) Grout : BUTECH COLORSTUK RAPID Colour : TBC Joint width : 2mm (for Solid Back Mosaic Tiles and Interlocking Tiles refer to clause 910) Movement Joints (WALLS)Perimeter sealant movement joint as clause 622

Sealant : BUTECH S-107 N Colour : TBC

Accessory : Tile edge trim Description : BUTECH PRO-MATE

Cleaning prior to As clause 995 handover :


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114. GENERAL FLOOR TILING TO WOODEN FLOORS

Tiles : PORCELANOSA, VENIS AND CERANCO GRES FLOOR TILES Size : 316 x 316 x 10mm to 602 x 602 x 10mm Tiles : URBATEK PORCELAIN FLOOR TILES Size : 300 x 600 x10mm to 600 x 600 x 10mm Tiles : PORCELANOSA AND VENIS PARQUET FLOOR TILES Size : 140 x 900 x 10mm to 220 x 900 x 10mm (laying as per clause 915)

Base/Background : 22mm tongue & groove P5 chipboard flooring Preparation : General preparation as clause 300

Apply priming coat of BUTECH UNIVERSAL BONDING AGENT as clause 462/a Over lay the floor with 6mm WBP plywood screw fixed at 200mm centres using counter sunk 25mm screws as clause 475

Bedding : BUTECH SOLID-BED/SOLID SURFACE (FLOORS): as clause 830 Adhesive : BUTECH SUPERFLEX S2 RAPID Grout : BUTECH COLORSTUK RAPID Colour : TBC Joint width : 3mm(for Ceramic Parquet refer to clause 915) Movement Joints (FLOOR) Perimeter sealant movement joint as clause 624

Sealant : BUTECH S-107 N Colour : TBC

Cleaning prior to As clause 995 handover :


116. GENERAL FLOOR TILING TO SAND AND CEMENT SCREED

Tiles : PORCELANOSA, VENIS AND CERANCO GRES FLOOR TILES Size : 316 x 316 x 10mm to 602 x 602 x 10mm Tiles : URBATEK PORCELAIN FLOOR TILES Size : 300 x 600 x10mm to 600 x 600 x 10mm Tiles : PORCELANOSA AND VENIS PARQUET FLOOR TILES Size : 140 x 900 x 10mm to 220 x 900 x 10mm (laying as per clause 915) Base/Background : New polymer modified cement : sand screed (unbonded), see addendum

M10 Preparation : General preparation as clause 300 Bedding : BUTECH THICK BED SOLID BED TROWEL (FLOOR) as clause 830 Adhesive : BUTECH PORCE-QUICK (Grey) Grout : BUTECH COLORSTUK RAPID or BUTECH COLORSTUK 2-12 GREY Colour : TBC


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Joint width : 2mm Movement Joints (FLOOR) Perimeter sealant movement joint as clause 624 Sealant : S 107 N

Colour : TBC Intermediate preformed strip movement joint as clause 626 Sealant type : S-107 N Strip Ref : BUTECH PRO-DILATA

Cleaning prior to As clause 995 handover : GENERAL REQUIREMENTS 200 BUTECH PRODUCTS:

To be applied strictly in accordance with the sitework instructions on the relevant product data sheets. For further information contact BUTECH, Technical Advisory Service, on 01827 25 44 90

210 INSTALLATION: To be carried out by trained operatives using safe working methods and where necessary, suitable protective clothing and equipment.

220 SUITABILITY OF BACKGROUNDS/BASES: - Before starting work ensure that backgrounds/bases are: - Sufficiently flat to permit specified flatness of finished tiling, bearing in mind the permissible

minimum and maximum thickness of the bedding material. - Suitable for tiling in the service conditions to which it will be exposed. - Sufficiently strong and rigid to support the tile finish. - If any of the above requirements are not met, inform the site supervisor and await

instructions.

223 NEW GYPSUM PLASTER: Before commencing work ensure that plaster has been allowed to dry out by exposure to air for at least 4 weeks. If the surface to be tiled is dusty, this is to be removed by thorough dry brushing and the surface primed using BUTECH-UNIVERSAL BONDIND AGENT (diluted 1:1 with clean water).

225 NEW SAND/CEMENT SCREEDS: Before commencing tiling, ensure that screeds have been allowed to dry out by exposure to air for at least 3 weeks.

230 FALLS IN THE BASE: Before starting work, check that where required, falls have been provided in the base. Inform the CA if the falls are inadequate. Do not attempt to provide falls by increasing or decreasing the specified thickness of the bedding material unless fixing by the semi-dry cement: sand bedding method.

246 SCREEDING: The screeding (specified in section M10) to receive tiling to be carried out by the tiling subcontractor or under their direct supervision and to their approval.

280 SAMPLES: Before placing orders submit representative sample(s) every different WALL TILE TBC or FLOOR TILE TBC from PORCELANOSA, VENIS or URBATEK. Ensure that delivered materials match sample(s).


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290 CONTROL SAMPLE(S): Complete sample area(s), being part of the finished work in approved location(s) as follows and obtain approval of appearance before proceeding.

PREPARATIONS

300 EXISTING BACKGROUNDS/BASES GENERALLY: - Remove efflorescence, laitance, dirt and other loose material. - Remove deposits of oil, grease and other materials incompatible with the bedding.

Clean down all areas to be tiled by washing with water containing detergent then with clean water.

- Paint and other non-porous surface products should be removed or suitably scored to ensure that the area to be tiled is porous in order that the adhesive can dry out.

- Allow background/base to dry before fixing tiles.

352 TONGUE & GROOVE FLOORBOARDS:

The boards are to be: - In good condition, dry, securely screw fixed and that the fixings do not protrude. - Screw fixed to supporting joists at a maximum of 300mm centres. Where necessary, noggins

are to be inserted to allow fixing at 300mm centres.

340 GYPSUM PLASTERBOARD BACKGROUNDS:

- Ensure that sheets are dry, securely fixed and rigid with no protruding fixings and the face intended to receive the decorative finish is exposed.

- Gypsum plasterboard is a suitable background where the weight of tiling does not exceed 32 kg/m² (equivalent to tiles with a thickness of 12.5mm).

- The plasterboard should comply with BS 1230: Part 1 and be: o Type 3 where there will be any exposure to moisture. o Not less than 12.5mm thick. o Fixed with screws or nails at 300mm centres both horizontally and vertically to

seasoned timber or suitable proprietary framed supports. - Rigid and free from springiness and surface undulations. - Plasterboard wall linings fixed with plaster dabs or adhesive should be allowed to stand for

10 days before being tiled.

462/a PRIME WITH BUTECH UNIVERSAL BONDING AGENT: Brush apply the undiluted primer to the 6mm WBP plywood overlay and allow to dry.

475 INSTALLATION OF 6mm WBP PLYWOOD OVERLAY: Ensure the tongue and groove chipboard flooring is clean and dust free. Lay the 6mm WBP plywood at right angles to the chipboard flooring using 25mm counter sunk screws at 200mm centres.

FIXING

600 FIXING GENERALLY: - Check that there are no unintended colour/shade variations within the tiles for use in each

area/room. Thoroughly mix variegated tiles. - Cut tiles neatly and accurately. - Work in small areas to ensure tiles are fixed within the open-time of the adhesive. - Before bedding material sets make adjustments necessary to give true, regular appearance

to tiles and joints when viewed under final lighting conditions. - Clean surplus bedding material from joints and face of tiles without disturbing tiles.

610 ADVERSE WEATHER: - Do not fix tiles if the temperature is below 5°C or in damp conditions. - Do not use frozen materials or apply adhesives to frozen or frost covered surfaces. - Do not fix tiles if the temperature of the background/base is in excess of 65°C.


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- Take adequate precautions to protect work from inclement weather, frost and premature drying out.

620 SETTING OUT GENERALLY: - Joints to be true to line, continuous and without steps. - Joints on walls to be truly horizontal, vertical and in alignment round corners. - Joints in floors to be parallel to the main axis of the space or specified features. - Cut tiles/slabs to be kept to the minimum, as large as possible and in unobtrusive locations. - Joints in walls and floors to be in alignment. - Where positions of movement joints are not specified they are to be agreed with the CA. - Before laying tiles obtain approval of setting out.

622 SETTING OUT MOVEMENT JOINTS (INTERIOR WALLS): Provide movement joints in tiling:

- Over existing and/or structural movement joints. - At abutments with other surfaces. - Over junctions between different background materials. - At internal vertical corners. - At 6 m centres horizontally and vertically. - Joints to be at least 6mm wide and extend through tiles and bedding to the substrate. - Joints located over structural movement joints should also extend through any intermediate

substrate and be 40mm wide

624 SETTING OUT PERIMETER MOVEMENT JOINTS (FLOORS): - Provide movement joints in tiling at floor perimeters including abutments with walls,

columns, upstands/bases, etc. - Joints to be at least 6mm wide and extend through tiles and bedding to substrate.

626 SETTING OUT INTERMEDIATE MOVEMENT JOINTS (FLOORS): Provide movement joints in tiling:

- Over existing and/or structural movement joints. - Over junctions between different base materials. - Over supporting walls and beams. - Joints to be at least 6mm wide and extend through tiles and bedding to the base. - Joints located over existing structural movement joints should extend through any

intermediate substrate and be 40 mm wide.

630 LEVEL OF FLOOR TILING: Permissible deviation in level from datum for 2m to be +/- 1.5mm.

640 FLATNESS OF TILING: Sudden irregularities not permitted. When checked with a 2m straightedge with 3mm thick feet at each end, placed anywhere on the surface, the straightedge should not be obstructed by the tiles and no gap should be greater than 6mm.

650 LEVEL OF TILING ACROSS JOINTS: Maximum deviation between tile surfaces either side of a joint, including movement joints to be 1mm for joints less than 6mm wide and 2mm for joints 6mm or greater in width.

730 ADHESIVE BEDDING: NOTCHED TROWEL (WALLS): - Use a BUTECH-ROUND NOTCHED WALL TROWEL. - Apply adhesive to dry background in areas up to 1m². For porous backgrounds, apply a skim

coat of adhesive first and comb remaining adhesive while skim coat is still wet. - Fill any depressions (ribbed, keyed profiles, etc.) to backs of tiles with adhesive. - Press tiles firmly into adhesive with a twisting/sliding action.

Ensure that the adhesive wets the back of each tile and achieves an area of contact of at least 75%.


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830 ADHESIVE BEDDING: SOLID-BED/SOLID SURFACE (FLOORS): - Use a BUTECH-SOLID-BED TIPPED TROWEL. - Apply adhesive to dry base in areas up to 1m². For porous bases, apply a skim coat of

adhesive first and comb the remaining adhesive while the skim coat is still wet. - For tile sizes above 33.3x33.3cm (or above 1000 sq.cm) a thin coat of adhesive should be

applied to the back of each tile ensuring that any depressions (ribbed, keyed profiles, etc.) are filled with adhesive.

- Press tiles firmly into position with a twisting/sliding action ensuring that as far as possible no voids are left beneath the tiles and that a solid layer of adhesive exists at the bottom of the tile joints.

880 CHECKING CONTACT AREA:

As work proceeds and before bedding has set, carefully remove random tiles to verify that contact area is as specified. Remove the initial bedding material, butter the removed tiles with fresh material and refix.

GROUTING / COMPLETION

900 GROUTING: - Allow bedding material to harden sufficiently before grouting. - Ensure that joints are 6mm deep (or the depth of the tile if less) and are free from dust and

debris. - Fill joints completely using a rubber grouting squeegee, tool to an approved profile, clean off

surface and leave free from blemishes.

- When using very dark coloured or black grout always check that it is suitable for use with the tiles that are being fixed to avoid colour bleeding.

910 SOLID BACKED MOSAICS AND INTERLOCKING TILES

- For Solid Backed Mosaics the size of the required joint is dictated by the grout joint which is pre-formed within the face of the tile. The required joint size is normally 1mm, but tiles should be fixed with the correct joint to ensure that the finished effect is of a continuous mosaic and not individual tiles.

- Interlocking Tiles give the appearance of a ‘butt joint’ but there is sufficient space for the joint to be filled with grout. Grout must be especially worked into the joint to ensure that they are completely filled.

915 CERAMIC PARQUET

- A maximum joint of 2mm should be used in all instances. Tiles should be laid randomly staggered to emulate natural wood flooring.

920 SUITABILITY OF MOVEMENT JOINTS: Before commencing, check that:

- Joint dimensions are within limits specified for the sealant. - Surfaces are smooth and undamaged . - Preparatory work which must be done before assembly of the joints has been carried out. - Inform CA if joints are not suitable to receive sealant and submit proposals for rectification.

930 PREPARING MOVEMENT JOINTS: - Clean surfaces to which sealant must adhere using methods and materials recommended by

sealant manufacturer. - Remove all temporary coatings, tapes, loosely adhering material, dust, oil, grease and other

contaminants which may affect bond. - Keep joints clean and protect from damage until sealant is applied. - Backing strip, bond breaker, primer: Types recommended for the purpose by sealant

manufacturer.


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- Insert backing strips and/or bond breaker tape into clean joints leaving no gaps. If the adhesive used to fix the tiles is BUTECH ONE-FLEX N or BUTECH PORCE_QUICK, ensure that a backing strip / masking tape prevents contact between silicone sealants and the adhesive.

- Cover adjacent surfaces with masking tape to prevent staining and protect surfaces which would be difficult to clean if smeared with primer or sealant.

950 APPLYING SEALANTS: - Ensure that operatives observe the manufacturer's and statutory requirements for storage

and safe usage of sealants. - Use equipment and methods recommended by sealant manufacturer and apply within the

recommended application life of primer and sealant, and the recommended air and substrate temperature ranges.

- Do not apply to damp surfaces (unless recommended otherwise), to surfaces affected by ice or snow or during inclement weather. Do not heat joints to dry them or raise the temperature.

- Fill joints completely, leaving no gaps, excluding all air and ensuring firm adhesion of sealant to required joint surfaces. Tool the sealant to a neat, slightly concave profile unless specified otherwise.

- Protect until cured.

960 PROTECTION (GENERAL): Adequately protect and keep clean all completed areas. Clean off any droppings immediately.

992 TRAFFICKING: When using BUTECH's rapid setting cementitious adhesives keep floors clear of traffic for at least 3 hours and permit light traffic only for the next 3 days. Do not allow the floors to be subjected to heavy traffic for at least 7 days after completion.

995 CLEANING TILES PRIOR TO HAND OVER: It is essential to remove all grout and polymer residues, some of which are not visible to the naked eye along with building grime that will be left on the surface after installation. Failure to do so may leave tiles difficult to clean and affect their aesthetic look. FILA Deterdek diluted 1:5 in water should be used in conjunction with the instructions on the product label. Floors should be vacuumed once dry to ensure all residues have been removed. Transit wax residue should be removed from polished porcelain using Fila PS87 diluted 1:5 in water used in conjunction with the instructions on the product label. In case of technical queries contact [email protected]

BUTECH ADDENDUM M10: SCREED

1010 SUITABILITY OF BASES TO RECEIVE SCREEDS: - Before starting work ensure that concrete bases are:

o At least 6 weeks old and thoroughly dry. o Sufficiently flat to permit specified levels and flatness of finished surfaces, bearing in

mind the permissible minimum and maximum thicknesses of the screed. o Clean and free from plaster, dirt, dust and oil.

1040 POLYMER MODIFIED CEMENT: SAND SCREEDING MORTAR: - Unless specified otherwise:

o Cement: Portland to BS 12, class 42.5. Sand: To BS 882, Table 4, grading limit C or M.

o Mix proportions: 1:3-1:4.5 batched by weight. Proportions are for dry sand, allow for bulking if damp.

o Modify the gauging water with BUTECH UNICEM at the rate of 10 litres per 50kg of cement.


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o Mix materials thoroughly to a uniform consistency in a suitable forced action mechanical mixer. Use the minimum amount of water necessary to give required workability.

o Use Portland cement mortar within 2 hours of mixing at normal temperatures. Do not use after the initial set has taken place and do not re-temper.

1060 SLURRY BONDING COAT: - For screeds using Portland cement: Mix by weight 1 part Portland cement to BS 12, class

42.5 to 1 part BUTECH UNICEM. - Brush onto base immediately before applying screed.

N.B.: It is important that the bonding coat is not allowed to dry out or set before the screed is placed, otherwise it will form a weak layer between the screed and the base, preventing effective bonding.

1080 SEPARATING LAYER: Lay sheets of polyethylene not less than 65 microns thick (250 gauge) on base and lap all joints not less than 100mm.

1100 LAYING UNBONDED SCREED: - Thickness of screed: Minimum at any point 50mm and maximum at any point 70mm. - Unless specified otherwise cast screed continuously, as far as possible without defined

joints, using either 'wet screeds' between strips/bays or screed battens accurately levelled to achieve the required thickness. Obtain approval for positions of bay joints.

- Lay screed onto a separating layer, as clause 1080. Compact screed thoroughly by heavy tamping or by mechanical means. Strike off any excess material using a rule/straightedge.

- Form vertical joints at day work/ bay joints. - Finish with a wood float.

1125 FLATNESS OF FLOOR SCREED: Sudden irregularities not permitted. When measured with a slip gauge to BS 8204: Part 1, Figure 3 or equivalent, the variation in gap under a straightedge (with feet) placed anywhere on the surface to be not more than:

5mm under a 3m straightedge. 2mm under a 1m straightedge.

1130 CURING:

Unless specified otherwise: - Immediately after laying, protect surface from wind, draughts and strong sunlight. - Screeds containing Portland cement to BS 12, class 42.5: As soon as screed has set, closely

cover with polyethylene sheeting for not less than 7 days. Allow to air dry for a further 14 days before tiling.

trade specification for ceramic wall/floor tiler...ceramic floor tiles (customer upgrade) 4.14 the...

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