Specifying anhydrite for Eastleigh apartments and new plots
Calcium sulphate screed is graded by two numbers. In a designation such as CA-C25-F5, CA means calcium sulphate, C25 is the compressive strength and F5 the flexural strength, both in N/mm2 as the BS EN screed standard defines them. Three grades cover most housing and offices:
CA-C20-F4 for domestic floors with light traffic. CA-C25-F5 for most homes, apartments and offices. CA-C30-F6 for heavier use.
On apartment buildings and new build plots, the engineer or developer names the grade and we pour to it. Occasionally the specification asks for an alpha hemihydrate product in place of a CA grade. Those are used where faster drying or a thinner section is needed, and each follows its own product sheet, which we work to.
The practical strength of calcium sulphate is its low shrinkage. It sets with very little movement, so large bays can be poured with few joints. That suits open-plan apartments and the long, continuous floors of new homes. Where joints are needed, such as at door thresholds or between heating zones, the layout is agreed before the pour.
The borough covers Bishopstoke, Fair Oak, Boyatt Wood, North Stoneham and Chandler's Ford as well as the town, and new plots anywhere across it are treated the same way, with the grade confirmed in writing before the pour. Our anhydrite screed guide gives more background on the material.
Laitance and moisture checks on Eastleigh anhydrite floors
Anhydrite has one habit that must be dealt with. As it dries, a weak layer called laitance forms on the surface. Tile adhesive, levelling compound and flooring glue will not bond to it reliably, so once the moisture has come down, the laitance is sanded back and the bare screed is primed with a product made to work with calcium sulphate.
Drying is the next check. Before a manufacturer will let its product go over calcium sulphate, the screed often has to be drier than a cement one would need to be, so we take a hygrometer reading instead of trusting the date. Where underfloor heating is installed, calcium sulphate can usually be force dried with it from about 7 days.
The material is not for wet areas. A wet room, a walk-in shower or a floor that could see leaks should be poured in a cement based flowing screed, or laid by hand in cement screed for Eastleigh wet areas.
After sanding and priming, sheet vinyl and LVT may still need a skim to reach SR1, which is covered by our floor levelling service. For flow screed across the city boundary, see anhydrite screed in Southampton.
Anhydrite & Flow Screed prices in Eastleigh
Liquid flowing screed (which includes anhydrite): £24 to £31 per m² supplied and laid (MyJobQuote, August 2026), so £960 to £1,240 for 40 m². MyJobQuote does not say whether these figures include VAT. See our floor screeding cost guide or screed calculator.
Who lays your anhydrite and flow screed in Eastleigh
K & B Screeding’s own team, led by director Donatas Bardisevicius. Founded 2019, company 12298780.
See what customers say in our Google reviews and on our testimonials page.
Anhydrite & Flow Screed from Slough to Eastleigh
As the crow flies, our yard in Slough is about 49.6 miles from Eastleigh, which lies to the south-west. Postcodes here include SO50 and SO53, and Hedge End (4.4 miles), Southampton (5 miles), Romsey (6.5 miles) and Winchester (6.6 miles) are close by.
More on anhydrite screed, part of our screeding services.