Calcium sulphate grades on Solihull plots and apartments
Every calcium sulphate screed is given a coded grade under the screed materials standard. In that code, C gives compressive strength and F flexural strength, measured in N/mm2. Three grades cover most buildings. CA-C20-F4 covers lightly used domestic floors, CA-C25-F5 fits most houses, apartments and offices, and CA-C30-F6 is kept for harder wear.
For a new house the grade comes from the engineer, and that is the grade we pour. Where a thinner floor or quicker drying is needed, a scheme may call for an alpha hemihydrate product. Each of those has a product sheet setting its own minimum depth, drying and heating times, and we follow that sheet over any general rule.
The material has real advantages over cement on large floors. Shrinkage during curing is minimal, letting broad bays go down with few joints across an open ground floor or a run of apartments. Any joints, typically at doorways or where one heating zone meets another, are planned out with the bays before pumping starts.
Homes built since 2015 make up 5% of Solihull's stock, and flats of all kinds 15%. When an office at Birmingham Business Park or Monkspath is refitted with a flowing screed, CA-C25-F5 is the grade normally associated with office use. There is more on how the material behaves in our explainer on anhydrite screed.
Laitance, primers and moisture readings in Solihull
As it dries, calcium sulphate leaves a thin, weak skin on top, known as laitance. That skin must be sanded away before adhesive or compound is applied, or the new floor ends up stuck to a crust rather than the screed. When the floor is dry enough we sand it, then prime it with a product made to work on calcium sulphate. A primer intended only for cement may not be compatible with it.
Moisture is the second check. Flooring makers often allow less moisture in calcium sulphate than in cement, so a reading that passes on sand and cement may fail on anhydrite. We test with a hygrometer and compare the result with the limit for the flooring being laid. If the floor is heated, the system can normally help dry it from about 7 days, warmed up gradually. Our guide on screed drying times covers the timings.
Anywhere that could get wet is the wrong place for anhydrite. In a wet room, a walk-in shower or a utility room where a leak is possible, use a cement based flow screed or a hand-laid Solihull sand and cement floor. For specification work on schemes further east, see anhydrite screed in Coventry.
Anhydrite & Flow Screed prices in Solihull
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 Solihull
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 Solihull
On the map, Solihull sits north-west of Slough, about 77.7 miles from our base in a straight line (postcodes including B91, B26, B92 and B90), next to Kenilworth (9.7 miles), Redditch (10.1 miles), Coventry (11.4 miles) and Warwick (12 miles).
More on anhydrite screed, part of our screeding services.
