How Long Does Screed Take to Dry?

Walking on it vs laying a floor on it

You can walk on a sand and cement screed the next day, and on most liquid screeds after a day or two. That doesn't mean they're dry. Tiles, timber, vinyl and carpet need the screed to have lost most of its moisture first, and that takes far longer.

Sand and cement screed

The usual rule of thumb is about a millimetre a day for the first 40mm, and slower after that. A typical 65mm to 75mm floor can take around three months or more to dry fully in normal conditions. More on this screed: sand and cement screed.

Liquid screed

Liquid screed is often laid thinner, which helps it dry faster. Some products can be force-dried with the underfloor heating once they've cured, following the manufacturer's heating-up schedule. More on liquid screed.

Fast dry screed

Fast dry screed is made for tight programmes: walk on it the next day, and get floor coverings down in days rather than weeks, depending on the product and the depth.

What speeds drying up, and what slows it down

• Helps: good ventilation once the screed has set
• Helps: a steady, mild temperature in the house
• Helps: a thinner screed, where the floor build-up allows it
• Slows: cold, damp weather and closed-up rooms with no air moving
• Slows: plastering and other wet trades in the same rooms

Rough drying guide for sand and cement screed

This uses the common rule of thumb: a day per millimetre for the first 40mm, then about two days per millimetre after that. Real drying depends on the weather, heating and ventilation.

Curing comes before drying

For the first week or so, a cement screed needs to cure, not dry out fast. Keep strong sun, draughts and heaters off it so the surface doesn't dry before the inside, which is a common cause of cracking and a weak, dusty surface. Once it's cured, open up the house and let the air move.

Why different floor coverings care

• Timber and laminate: moisture from the screed can make boards swell and cup
• Vinyl and LVT: trapped moisture can lift the adhesive and cause bubbles
• Tiles: more forgiving, but adhesives still need the screed dry enough
• Carpet: the most forgiving, but the underlay can still sweat on a wet screed

Your floor fitter will know what their product needs. Ask them before you book the screed, so the dates line up.

Test before the floor goes down

Before tiles, timber or vinyl go down, your floor fitter should test the moisture in the screed. Laying too early is the main cause of lifting tiles and cupped timber floors.

From JAM Floor Screeding, Portlaoise. Over 20 years laying screed across Leinster. Figures here are typical guidance; your floor's spec and the manufacturer's data sheet always come first.