GENERAL SPECIFICATION FOR FIXING EXTRUDED TILES (GAIL, INTERBAU, NCI, VITRO, ETC) ONTO INTERIOR SURFACE BEDS AND SUSPENDED SLABS
Please note that ‘general’ specifications are issued for information purposes, and should not be used as project specifications.
As each and every project needs to be assessed individually on its own merits and characteristics please contact the TAL Technical Advice Centre for a project-specific detailed materials and methods specification for specific projects.
It is important that the tile selected is suitable for the application, preferably against a written Supplier’s specification. Factors such as water absorption, irreversible moisture expansion, MOR and PEI ratings, chemical resistance and overall stability of the product need to meet the requirements of the service conditions.
The backs of all tiles must be clean and free from dust and contaminants.
Please note that any “wet” areas, such as showers or balconies, should be waterproofed using TAL SUPERFLEX or TAL SUREPROOF waterproofing compounds prior to commencing tiling. Please feel free to contact us for a specification for waterproofing and tiling these areas, as well as for technical literature on any of our products.
TAL PRODUCT REQUIREMENTS
The TAL products required for this installation are as follows :
TAL KEYCOAT *
TAL GOLDSTAR 6
TAL BOND / TAL BOND POWDER
TAL WALL & FLOOR GROUT / TAL QUARRYGROUT
NOTCHED FLOOR TROWEL
TAL SEALMASTER CORD
TAL GOLDSTAR SEALMASTER 1000
Special note must be taken of the following:
These tiles (extruded, glazed and/or unglazed stoneware) tend to have characteristics similar to those of porcelain tiles, ie low water absorption rates (0.5% or less) and dense bodies, necessitating the use of adhesives with higher bond strengths than conventional (standard-setting) adhesives.
We have specified the use of TAL GOLDSTAR 6 rapid setting high strength adhesive for the installation of these tiles. However, if timing on this project allows for a quick setting adhesive option, then TAL GOLDSTAR 12 can be considered.
The advantages of using TAL GOLDSTAR 12 are as follows :
It is however important that newly installed tiles are protected from traffic (other trades, etc) for a minimum of 12 hours, while the adhesive sets. This is especially important in fast-track installations.
All surface beds should have a damp proof membrane (DPM / DPC). Should there be no damp proof membrane below a surface bed or if prevailing moisture levels do not attain 5% (75% RH) or less, it is recommended that TAL X-CALIBUR X-SHIELD VAPORSTOP HB (vapour barrier) be applied prior to tiling to eliminate potential problems associated with excessive moisture in the substrate (such as slow- or non-curing of the adhesive, efflorescence on grout and porous tiles, etc).
TAL X-CALIBUR X-SHIELD VAPORSTOP HB is a moisture tolerant, 100% solids epoxy barrier coat that prevents the passage of water vapour and moisture through concrete slabs.
Please contact TAL for more information on the application of VAPORSTOP HB.
Suspended Applications :
Tiling onto SUSPENDED concrete slabs require special precautions to be taken as the installation is prone to increased movement caused by slab deflection and creep, loading on the slab, etc. TAL BOND or TAL BOND POWDER needs to be incorporated in the adhesive and grout mix, or a single part flexible adhesive such as TAL GOLDFLEX needs to be used to allow for the increased movement.
NOTE : All Ground Floor levels with Basement / Parking levels below should be construed as SUSPENDED slabs.
- BACKGROUND PREPARATION
- Allow all new concrete work and screeds to cure for at least 6 weeks and 4 weeks respectively before proceeding. All new concrete work and screeds must have a moisture content of 5% or less before tiling can be commenced. When tiling directly onto concrete, ensure that the surfaces are clean and free of all traces of curing agents, laitance and any other surface contaminants, preferably by scarifying.
- Any screeding must be firmly attached to the underlying concrete, must be integrally sound (no crumbling, cracking, etc) and must be of a quality and consistency suitable for tiling. All damaged, defective, deteriorated or hollow sounding areas must be removed and the floor made good before proceeding. The surface must be clean and dry and free of all traces of dust, debris, loose particles and surface contaminants.
- If the surface has been woodfloated (rough) it is possible to commence tiling. However, if the surface has been powerfloated or steelfloated (smooth, dense) it will be necessary to first key the surface with a slurry consisting of 1 part TAL KEYCOAT to 2 parts TAL KEYMIX powder or 2 parts TAL GOLDSTAR 6 or 12 powder (by volume), which is applied by block brush. Allow this slurry coat to dry for 4 – 6 hours before applying the adhesive. *
- ADHESIVE SYSTEM
- Surface Beds
- Apply TAL GOLDSTAR 6 rapid-setting adhesive to the background using a notched trowel.
- Suspended Slabs
- Apply TAL GOLDSTAR 6 rapid-setting adhesive mixed 20kg with 5 litres of TAL BOND (replacing the water in the mix) to the background using a notched trowel.
Alternatively, TAL BOND POWDER may be added to the adhesive mixing water at a ratio of 1 x 1kg sachet per 20kg TAL GOLDSTAR 6, or TAL GOLDFLEX single-part flexible rapid-setting adhesive may be used. When using TAL GOLDFLEX no additives are required, simply mix with clean water, alleviating possible mixing errors on site.
- In this tiling situation it is imperative that there is a solid bed of adhesive at least 6mm thick beneath each tile. We would recommend the use of a notched FLOOR TROWEL.
- At no time spread more adhesive than can be tiled onto in 10 – 15 minutes. Depending on atmospheric conditions, this will normally be around 1 square metre. This prevents the adhesive from drying or “skinning” before the tiles are applied.
- Bed dry tiles (do not soak) firmly into the wet adhesive with a twisting action to ensure full contact between the background, tiles and adhesive. Tiles should be well tapped home with a rubber mallet or the wooden handle of a trowel. It is sound practice to remove the occasional tile to ensure that good contact has been achieved.
- When using heavily lugged tiles, or tiles with a very irregular back profile, it is good practice to butter the back of each tile, ensuring that the grooves or dovetails are completely filled with adhesive.
- Clean off any surplus adhesive remaining on the face of tiles and between the joints with a damp sponge before the adhesive dries.
- Never butt joint tiles. Joints are required to allow the individual tiles to move with respect to each other and thus avoid a compressive stress build-up. They are also required as vents for the tile adhesive to cure. The joints between these tiles must be a minimum of 5mm wide, or as per manufacturer’s instructions.
- Pot life of the adhesive will vary with climatic conditions. Under no circumstances should adhesive which has been left standing for too long be reconstituted by adding more liquid.
- Do not tile over structural, expansion or cold joints in the background. These joints must be extended through the various layers to the surface.
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