Tiling uneven floors

It is important, both for appearance and for safety, that the finished tile surface is flat with no tiles standing higher than the others. Usually this is easy to achieve when tiling onto a flat and level surface, but if the substrate isn’t flat various problems can arise.

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Common issues and queries you can face

Increased difficulty in achieving a flat finished surface on the tiles

Increased difficulty in laying tiles evenly

Using a notched trowel at a constant angle enables even distribution of tile adhesive onto a substrate. If tiles are all bedded with a similar force, they should all be at a similar height with minimal unevenness. Where the substrate isn’t level, this is much more difficult and it is more likely tiles will end up uneven.

Extra time required to fill holes

Extra time required to fill in substrate

Deep holes in the substrate may result in a bed thickness that exceeds the specification for a thin bed adhesive. Patching such holes can be time consuming if there are more than a few of them. In this instance, a thick bed tile adhesive may be more appropriate solution.

Some natural stones are not a constant thickness

Some natural stones are not a constant thickness

Uncalibrated natural stones are those which have been split along natural fracture planes rather than machine cut. The result is a stone that varies in thickness, both from within each stone and from piece to piece. These types of stone require a thick bed tile adhesive that can be applied to a greater thickness than normal.

Combination of problems

Combination of problems

In some instances — for example when tiling over a layer of existing ceramic tiles — the previously mentioned problems may be combined. Some tiles may need to be removed because they are unsound, whilst others may have been imperfectly fixed and exhibit some variation in height.