Screed vs Self-Levelling Compound: Which Does Your Floor Need Before Tiling?

Why the floor matters so much

Tiles show every flaw in the floor underneath. An uneven substrate leads to lippage (tile edges sitting higher than their neighbours), hollow or drummy tiles and cracked grout. In a shower, a floor without the right falls leaves water sitting on the tiles. Getting the base right is the least visible part of a tiling job and the most important.

Sand-and-cement screed

• Mixed from sand and cement and packed, then worked to level or to a fall with a straight edge.
• Can be laid thicker than most levelling compounds, so it can raise floor levels.
• The standard way to create falls to a floor waste in showers and other wet areas.
• Needs time to dry before waterproofing and tiling.

Self-levelling compound

• A cement-based compound poured onto a primed floor that spreads out flat on its own.
• Suits correcting dips, humps and uneven concrete across living areas, kitchens and hallways.
• Each product has a minimum and maximum thickness, so it is not a substitute for building up large height differences.
• Finds its own level, so it cannot create a fall to a drain.

Which one does your floor need?

• Shower floors and wet areas with a floor waste: a screed with falls to the drain, then waterproofing.
• A slightly uneven concrete slab in a living area: often a self-levelling compound is enough.
• Timber floors being tiled: usually sheeting plus a levelling product, after checking the floor is stiff enough.
• Large differences in height, or steps between rooms: a screed, sometimes finished with a thin self-leveller.