How to level an uneven floor before tiling
Tiles — especially large ones — need a flat base. Here is how to level an uneven floor with SUMO Floorscreed so your tiling starts right.
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Tiling — especially large-format — needs a base flat to within a few millimetres, or you fight lippage and hollows the whole way. Rather than build up adhesive to fix a bad floor, you level the floor first with SUMO Floorscreed, a polymer-modified levelling and flooring-base mortar.
This guide covers levelling a floor ready for tiling.
What you’ll need
Step by step
Check flatness and set levels
Run a straightedge across the floor to find high and low spots and decide your finished level and any falls to drains. Mark reference levels.
Prepare and prime
Clean off dust, oil and loose material, and prime the substrate so the screed bonds to it.
Mix the screed
Mix SUMO Floorscreed to a workable, consistent mortar per its instructions. Mix batches you can lay before they stiffen.
Lay and rule off to level
Lay the screed and rule it off to the marked levels/falls with a straightedge, working to a flat, true surface. Compact it well.
Cure before tiling
Let the screed cure for the recommended time before tiling. Then fix tiles (S03/S04 for large format) on the flat base.
Care, tips & what to avoid
- !Tiling on an unlevelled floorAdhesive cannot bridge big dips. Level the floor first — especially for large tiles.
- !No primerScreed debonds from an unprimed, dusty base. Prime it.
- !Tiling too soonTiling a green screed risks movement and cracks. Let it cure.
