Substrates
some of the boards so 'bearers' can be fitted below to provide further support.
should be correctly commissioned prior to tiling and switched off during tiling. There must be no cracks in the screed otherwise
If your tiling is to last, it is essential that the surface onto which the tiles are to be laid is sound. Careful consideration must be given to the floor surface to confirm that the surface is level, clean, dry, free of dust, grease and any loose material.
Your tiler must confirm the suitability of the subfloor before tiling.
Sand and cement screeds
When tiling onto a new screed, a minimum period of one week for each 25mm of new screed should elapse to allow the screed to be suitably dry. Further time may be necessary, depending on weather and site conditions. We do not recommend tiling onto anhydrite or fast setting screeds without careful consideration - please contact our Technical Department for further advice.
A new screed may shrink as it dries, and this may result in cracks across the screed. If cracking does occur it is likely to appear across any tiles that are fixed to the screed. Ensure that the screed is suitably dry and stable before any tiling is started.
Any movement or day joints in the screed must be carried through into the tiled surface. Day joints or construction joints must not be tiled over without the inclusion of an expansion joint.
Bumps and hollows in screeded floors
Minor irregularities can be overcome with up to 5mm of Fired Earth Universal Levelling Compound* or Fired Earth Thick Bed Adhesive*. If the floor is very uneven, with undulations of more than 5mm, Fired Earth Universal Levelling Compound* should be used in conjunction with clean granite chippings.
Suspended timber floors/
Floating insulated floors
Suspended timber floors/floating insulated floors (polystyrene with water resistant chip board over) should be rigid, non- flexing and stable enough to bear the additional load. In order to minimise the damaging effect of lateral movement in the floor surface, it is recommended that the floor is prepared using Fired Earth Fleximat*. Our Sales Team will be happy to provide our separate information sheet.
If the suspended timber floor is subject to vertical movement, the floor must be stiffened. Remove flexing by fixing a minimum 18mm, WBP plywood over the existing timber, screwed down at 150mm centres. If the floating insulted floor is subject to vertical movement the floor must be braced by screwing and gluing WPB plywood to its surface, or removing
Seal all the surfaces of the plywood boards with Fired Earth Universal Bonding Agent*
Other types of floors
Fired Earth would recommend that all existing floor covering and residue adhesive are removed before tiling. However it is possible to tile over existing tiles provided the surface is completely sound, secure and thoroughly cleaned to remove all contaminants such as oil, wax and grease, using an appropriate cleaner.
Cork and woodblock floors must be removed and any bitumen left on the subfloor should be scraped away and all loose material removed.
Vinyl tiles must be primed with Fired Earth Universal Bonding Agent*.
Damp
Prior to fixing tiles, damp of any nature should be rectified. Consult a specialist if any doubt exists.
Finished floor level
The finished level of an existing floor will be raised by the maximum thickness of the tile plus approximately
Underfloor heating
Fired Earth floor tiles can be used over most underfloor heating systems. The heating
any floor tiles fitted on top will crack.
Fired Earth Fleximat* can be used as an
Always use flexible adhesive and grout and provide an expansion gap around all perimeters and abutments. As a general guide, do not tile continuously over areas with a length of over 6 metres, fit an expansion gap to prevent stress building up in the floor. Always fit expansion joints in doorways of adjoining tiled rooms.
DO NOT switch the heating on for at least two weeks after tiling, then, starting from ambient temperature, do not increase the temperature by more than 5°C in a 24 hour period until the normal working temperature is reached.
'Wet' floors
Please refer to our Waterproofing Showers and Bathrooms Installation Guide for further advice.
Walls
When tiling onto walls with floor tiles, consideration must be given to the weight of the tile and suitability of the substrate. Our Sales Team will be happy to confirm the weight of any of our tiles.
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