The quality of all tiling is strongly influenced by the condition of the surface you tile over, so it's important to ensure that your floor is firm and structurally sound, level and clean of oil, grease, dust and debris before you start tiling.
If the concrete is new, it must be allowed to cure for at least 28 days before it's tiled over. The rule of thumb for concrete curing is generally 1 week for every 25mm of slab thickness. Remember while concrete is hard and strong, new concrete does shrink slightly over time so it is best to use an underlay, flexible adhesive and of course, incorporate movement joints into your tiling, to allow for this. Talk to your Beaumont store for the best product to suit your project.
If the concrete is steel-trowelled, it will need to be mechanically roughened (and then thoroughly cleaned) before tiling, otherwise, you will not get enough adhesion.
Any concrete release agents and curing compounds should be removed by mechanical means.
Any holes or irregularities should be filled with a suitable levelling compound 24 hours before laying the tiles. If the floor is too uneven or has the wrong “fall” it can be built up, after being chipped, with a 2:1 fine clean washed sand and cement mixture with a bonding agent additive. This building up is not easy and should only be done in cases where the surface is quite unsatisfactory. Concrete floors should be left with a wood float finish.
It is important to start with a flat floor, particularly when installing large tiles. Interior floors should have a maximum of 5mm variation across 3 metres. Where the underlying floor surfaces are not flat, a levelling compound may need to be applied before tiling.
For concrete with small hairline cracks under 1.5mm, apply a flexible underlay, decoupling mat or crack isolation membrane before tiling. We can help with a range of suitable products. For cracks in the concrete wider than 1.5mm and the best solution for your project, consult your local in-store experts.
Once all concrete, patching and levelling compounds are cured and dry, the next step is priming (if required) then tiling.
Our Hot Tip: Drying of concrete depends on the thickness of the slab and if polythene sheet is used under the slab or not. For best results, concrete must be allowed to cure for at least 28 days. Cement topping should be cured for 7 to 14 days.