Screed types · checked 29 October 2026
Sand and cement screed
The traditional floor screed: the mix, the depths, curing and drying, from the standards and the makers' figures.
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Figures checked against each source on 29 October 2026. How we check
A sand and cement screed is cement and sharp sand mixed with just enough water to hold together, spread over the slab or insulation, compacted and finished flat. It's the traditional floor screed in Irish houses and the one every builder knows.
BS 8204-1 recommends 1 part cement to 4 parts sand by weight, and no richer than 1:3 or leaner than 1:4.5, according to the Mineral Products Association. In a house a floating sand and cement screed is normally at least 65 mm deep.
Screed planner
Plan your screed
Put in your floor and the day it's laid. You get the volume, the weight, when it should be dry enough for floor finishes, and when the heating can go on, from the makers' own figures.
Drying times are for good conditions, closed up and ventilated. The floor is tested before finishes go down, not guessed. None of the Irish screeding contractors' sites we checked publish a price per m², so the price comes from your floor.
How deep it needs to be
The depth depends on what the screed sits on. The Mineral Products Association's screed data sheet sets out the BS 8204 figures:
| Construction (sand and cement) | Minimum | Normally specified |
|---|---|---|
| Bonded to the slab | 25 mm | 40 mm |
| Unbonded, on a membrane | 50 mm | 70 mm |
| Floating, on insulation, in housing | 65 mm | – |
| Floating, on insulation, other buildings | 75 mm | – |
Source: Mineral Products Association, Mortar Data Sheet 22: Screeds (Issue 3, October 2023). Checked 29 October 2026.
A bonded screed is the least likely to crack, curl or sound hollow, the data sheet says, but the slab has to be prepared mechanically so the screed grips it. An unbonded screed suits a slab that's contaminated or already has a damp-proof membrane on top. A floating screed is the usual choice over insulation and underfloor heating. See bonded, unbonded and floating screed for the differences.
- Floor finish Tiles here; timber or vinyl once the screed is dry enough.
- Sand and cement screed 65 mm or more when floating in a house.
- Polythene Over the insulation, laps taped.
- Insulation Rigid boards, firm and flat.
- Slab With the damp-proof membrane under it.
The mix and the strength
BS 8204-1 says a screed mixed at those proportions will meet the in situ crushing resistance it expects, and so will a screed of strength class C20 or C25. Factory-made screeds have to meet BS EN 13813, while screeds mixed on site are normally made to BS 8204.
A screed's hardness on site can be tested with the BRE screed tester: a 4 kg weight dropped 1 m onto an anvil four times, with the dent measured. The acceptable dent depends on the floor finish and how the floor is used.
Source: Mineral Products Association, Mortar Data Sheet 22: Screeds (Issue 3, October 2023). Checked 29 October 2026.
Curing and joints
A sand and cement screed has to be cured. The Mineral Products Association says it should be covered with plastic sheeting or similar to keep the moisture in for at least five days.
It also needs joints. In its comparison with its own liquid screed, Gyvlon lists sand and cement bays at a maximum of 36 m², 6 m long and 2:1 in shape, and says a floating sand and cement screed needs D49 mesh or fibre reinforcement. Those are a liquid screed maker's figures, so ask your contractor what bay layout they work to.
Sources: Mineral Products Association, Mortar Data Sheet 22: Screeds (Issue 3, October 2023); Gyvlon flowing screed general data pack (Anhydritec). Checked 29 October 2026.
How long it takes to dry
BS 8204-1 allows one day per mm of thickness for the first 50 mm, so a 50 mm screed should be dry enough in about two months in good conditions. Beyond 50 mm, two days per mm is the generally accepted figure, and Ronacrete expects a 75 mm screed with no additive to take about 100 days to reach 75% relative humidity.
Source: Ronacrete, Drying of Screeds. Checked 29 October 2026.
Most floor finishes need the screed at or below 75% relative humidity. If the dates are tight, a fast-drying screed uses the same method with a different binder. See screed drying time for the full picture.
When sand and cement suits
- A floor that needs falls, such as a wet room. A levelling screed can provide falls, the MPA notes, and Roadstone says its FlowPlus liquid screed can't be laid to falls.
- Small areas, single rooms and patch repairs, where a liquid screed pump isn't worth setting up.
- Bonded screeds on a sound slab, from 25 mm.
- Builds where the contractor and the floor finisher are both used to sand and cement and its drying times.
Sources: Mineral Products Association, Mortar Data Sheet 22: Screeds (Issue 3, October 2023); Roadstone FlowPlus cement liquid screed brochure (RS.BRO-19 Rev 01, March 2022). Checked 29 October 2026.
Bagged sand and cement screed
For small areas, pre-mixed bags save batching on site. McMahons lists Kilsaran's KPRO Floor FLS 401 sand and cement screed at €11.90 ex VAT (€14.64 incl. VAT) per 25 kg bag. A whole floor takes a lot of bags: at around 2,100 kg per m³, 1 m² at 50 mm weighs about 105 kg. See floor screed cost for the arithmetic.
Sources: McMahons: Kilsaran KPRO Floor FLS 401 S&C Screed 25 kg; Roadstone FlowPlus cement liquid screed brochure (RS.BRO-19 Rev 01, March 2022). Checked 29 October 2026. The density is the dry density Roadstone gives for its FlowPlus screed, used here as a guide only.
What the quote should say
- Bonded, unbonded or floating, and the depth
- The mix or strength class, and whether fibres or mesh are included
- Who lays the edge strip and the polythene
- Where the joints go
- How the screed is cured, and for how long
- When you can walk on it, and when the floor finish can go down
Questions people ask
What is the mix for a sand and cement floor screed?
BS 8204-1 recommends 1 part cement to 4 parts sand by weight, with limits of 1:3 and 1:4.5, according to the Mineral Products Association.
How thick should a sand and cement screed be?
Bonded to the slab: at least 25 mm, normally 40 mm. Unbonded: at least 50 mm, normally 70 mm. Floating on insulation: 65 mm in housing, 75 mm otherwise. These are the BS 8204 figures in MPA's data sheet.
How long does a sand and cement screed take to dry?
About one day per mm for the first 50 mm under BS 8204-1, so two months for 50 mm in good conditions. Ronacrete puts a 75 mm screed at about 100 days.
Does sand and cement screed need to be covered?
Yes. The MPA says it should be covered with plastic sheeting or similar for at least five days to cure.
Can sand and cement screed go over underfloor heating?
Yes, as a floating screed. The MPA's minimum for a floating screed in housing is 65 mm, and Designing Buildings Wiki gives 65–75 mm as the ideal range over heating.
Sources (5)
Prices and facts on this page were checked against these published pages. We are not connected to these businesses.
- Mineral Products Association, Mortar Data Sheet 22: Screeds: mortar.org.uk
- Gyvlon flowing screed general data pack (Anhydritec): specifiedby.com
- Ronacrete, Drying of Screeds: ronacrete.co.uk
- Roadstone FlowPlus cement liquid screed brochure: roadstone.ie
- McMahons: Kilsaran KPRO Floor FLS 401 S&C Screed 25 kg: mcmahons.ie
Get your floor priced
Four taps about the job and one screeding contractor who covers your county rings you. Or call 087 162 1846, lines open 8am to 8pm.