When can you tile on new screed?

Short answer: you can tile when the screed has dried to the moisture level the tile adhesive manufacturer requires, commonly 75% relative humidity or lower, measured with a hygrometer. For a typical 65 mm sand and cement screed that can take two to three months naturally; liquid and fast-drying screeds can be ready much sooner. Calcium sulphate liquid screeds also need sanding and priming first.

Test, do not guess

A screed can look and feel dry on top while still holding plenty of moisture below. A hygrometer test, where a sealed hood sits on the floor until the air inside matches the screed, gives a reliable reading. Your tiler or our team can carry it out.

Typical timings

• Sand and cement, 65 mm floating: roughly 2 to 3 months in good drying conditions.
• Liquid calcium sulphate, 40 to 50 mm: often 5 to 8 weeks, sooner with underfloor heating force-drying once allowed.
• Fast-drying systems: days to a couple of weeks, depending on the product.

Preparing a liquid screed for tiles

1. Sand off the surface laitance, the weak, glassy top layer.
2. Vacuum thoroughly.
3. Confirm the moisture level.
4. Apply a primer compatible with calcium sulphate screeds and the chosen adhesive.
5. Use an adhesive suitable for calcium sulphate screeds, or a decoupling membrane, as the manufacturer specifies.

Over underfloor heating

The heating should be commissioned with a gradual heat-up and cool-down before tiling, so the screed has already been through its first temperature cycle. See our guide to the best screed for underfloor heating.

Quick answers

Can I tile sooner with an uncoupling membrane? Some membrane systems allow tiling on screeds with higher moisture levels. Follow the membrane manufacturer’s limits exactly.

What about wood and LVT? Timber floors often need a drier screed than tiles. LVT also needs a smoothing compound for a perfectly flat surface. See floor levelling.

Written by Ben Phillips, director of Chelmsford Floor Screeding Ltd, floor screeding contractors based in Billericay with 20+ years of experience across Essex and London. More about us.