11.1 General
11.1.1 Scope of Work
The scope includes supply and installation of hard floor tiles to the following main areas:
The Contractor should refer to the finishes schedule for details of specific tiling areas.
Ceramic tile flooring is specified under Section 14 ‘Ceramic Tiling’. The tile specification given in the following is intended for the purpose of quoting for installation only. The actual material will be specified by the Engineer in due course.
11.1.2 Relevant British Standards
Conform to the recommendations of the following British Standards where applicable:
BS 8000, Part II Code of Practice for Wall and Floor Tiling BS 4131 Terrazzo tiles
11.1.3 Literature and samples
Provide comprehensive technical literature on all proposed floor tiling products together with illustrations of all colours/patterns/textures available.
Selection of all material shall be to the approval of the Engineer.
11.1.4 Shop drawings
Provide detailed shop drawings showing patterned floor tiling where called for on the drawings, for the approval of Engineer.
11.2 Materials
11.2.1 Terrazzo tiles
The pre-cast terrazzo tiles and skirting shall be made from cement and coloured stone chipping as approved by the Engineer and manufactured in the Sultanate
shall be polished hard, durable and non-absorbent, of exact shape and even thickness and shall have sharp true edges and be the best of their respective types.
Floor tiles: 300 x 300 x 20mm pre-cast terrazzo floor tile with fine grit finish.
Stair treads: 600 x 275 x 30mm round edged tiles with two 5 x 5mm non-slip grooves shall be used for stair treads.
Colour, size of chips etc. to be specified by the Engineer at later date.
11.2.2 Marble Tiles or granite
20mm thick natural imported marble or granite tiles as noted in the finishes schedules. Standard size to be 300 x 300mm or 300 x 600mm unless otherwise indicated on the drawings.
Where used as a finish for stair treads the marble is to be 30mm thick to the profile shown on the drawings, and with a grit blasted flamed finish non-slip strip 40mm wide 20mm behind the nosing.
11.2.3 Skirting
Terrazzo : 300 x 150mm high, 20mm thick with chamfered top edge.
Skirting in conjunction with marble or granite finishes shall be 300x150mm high and finished in the same material as the floor.
Top edges of all skirting shall be chamfered or moulded to approved sample.
11.2.4 Non-slip Tiles and Skirting
Shower, bathroom and kitchen areas shall have an approved fully vitrified ceramic non-slip tile to approved colour and texture.
11.2.5 Cement
Ordinary Portland Cement to BS 12:1978, or Omani Standard No. OS7.
11.2.6 Sand
Clean sharp sand complying with BS 882:1983 (grading Zone 2 or 3) 11.2.7 Water
Clean potable water to comply with concrete specification.
11.2.8 Separating membrane Polythene sheet, 250 mµ thick.
11.2.9 Adhesives and Grouts
Adhesives and grouts should be fit for purpose in each area of use.
The following performance characteristics should be met:
• High compressive strength adhesive to take the weight of vehicles.
• High shear bond strength.
• Adhesive must be flexible to accommodate any vibration movement and impact.
• Grout to have a high compressive strength as well as being flexible.
• Grout to have high abrasion resistance.
• Grout to be stain resistant.
11.2.10 Adhesive System
Adhesive shall comprise of a “thin set” type bonding medium comprising latex adhesive with an inert filler powder; as per manufacturers specification.
11.3 Execution
11.3.1 Preparation
Ensure that all sub-bases for tiling (generally screeds) are thoroughly clean, dry and laid to the required levels and falls where applicable, before tiling work is commenced.
All surfaces which are to receive tiling to be left for at least 14 days after erection/ casting before tiling work is commenced.
11.3.2 Setting out
Lay out flooring material loose before cutting to approved layout/ pattern.
Lay out material to minimise cutting and avoid unduly narrow or small cut-offs.
Unless otherwise indicated on the drawings lay tiles with continuous joints running in both directions.
11.3.3 Laying of hard floor tiles Refer to Section 15 - fixing of floor tiles.
Refer to finishes schedules for location and type.
For terrazzo any of the above three approved methods of fixing may be employed.
11.3.4 Quality of tiling installation
The maximum permitted deviation from level will be 3mm under a 3m straight edge in any direction taking into account drainage falls where applicable.
Where cut tiles are necessary they shall be carefully cut with a suitable tool and rough edges rubbed smooth. Cut tiles which do not fit correctly shall be
replaced with properly cut tiles.
Ensure solid bedding of all tiles. Hollow sounding tiles to be replaced.
11.3.5 Grouting
Leave tiles for at least 12 hours before grouting joints.
Work grout well into joints until flush with face of tiles. Clean off surplus grout
Grouting procedure to be undertaken strictly in accordance with manufacturer’s recommendations.
11.3.6 Movement joints/separating strips
Provide movement joints to the full depth of tile and bedding at all wall/floor junctions and elsewhere if specified or so requested by the Engineer.
At wall junctions leave this joint empty of material ready for concealment by the skirting. Elsewhere joints to be sealed with backing material and sealant.
Install separating strips where hard flooring tiles abut other floor finishes or elsewhere as shown on the drawings. Ensure separating strips are perfectly flush with the tile surface.
11.3.7 Terrazzo polishing
All terrazzo surfaces are to be polished on completion. Large areas shall be wet polished by means of approved machines using a No.140 carborundum wheel.
Any surfaces too small for convenient machine polishing may be polished by hand, using a No. 140 carborundum stone and water. Care must be taken during any polishing operation not to damage any angles or arrases.
11.3.8 Skirting
Skirting shall be laid in such a manner that their vertical joints coincide with the horizontal joints in the floor tiles. The abutments against door frames shall be neatly formed.
11.3.9 Exposed stair treads
Lay the outer (exposed) treads on a thin - bed of two part epoxy adhesive, all as detailed on the drawings.
11.3.10 Completion
Leave floor finish clean and adequately protect the installation until handover.
11.3.11 Future Maintenance
As part of the contract, the Contractor shall store in a suitable place as advised by the Engineer/Client an additional 10% of the quantity of tiles used, for future use.