Anhydrite grades on Soham specifications
Anhydrite is the common name for calcium sulphate screed. Cement shrinks as it sets; this barely does, which allows broad bays with hardly any joints. It flows tightly around underfloor heating pipes, and it gives a flat surface for tiles, LVT or timber.
The grade appears on the drawings as a code. CA stands for calcium sulphate. Behind C sits compressive strength, behind F flexural, each given in N/mm2.
Domestic floors seeing little traffic can be CA-C20-F4. Homes, apartments and offices in the main get CA-C25-F5, and anything used harder steps up to CA-C30-F6.
Alpha hemihydrate products are an option where faster drying or a thinner section is important. Every one of those comes with its own data sheet, which governs how we pour it.
Apartment floors are one use. The screed usually sits over acoustic insulation, and bays and joints are laid out around doorways and corridors before the pour. New house plots are the other: drawings for a heated ground floor may call for a flowing calcium sulphate floor.
We prepare the full build-up with our own team and plan the joints first, so the pour goes to plan. If you are still weighing up pumped screed in general, see liquid screed in Soham. More on the material itself sits in what anhydrite screed is.
Finishing anhydrite floors in Soham homes
A calcium sulphate floor needs attention after the pour and before flooring.
Laitance comes first. As the screed cures, a weak, powdery film forms on top. When drying is done, it gets sanded away and the dust vacuumed up. Without that step, adhesives and levelling compounds may not bond.
Moisture testing is next. Flooring brands often want calcium sulphate drier than they would want cement, so nobody skips the hygrometer. On a heated Fordham Road plot, the pipes in the floor can usually begin force drying at about day 7.
Priming is last. Pick a primer whose maker approves it for calcium sulphate. Sanding and priming before the finish both come under our floor prep work.
The material has limits. Wet rooms, a boot room with a gully, an outbuilding: anywhere liable to get wet is off limits. A flowing cement screed goes there instead, and K & B can pour either.
All of this goes to you in writing when the pour is complete: the grade, the pour date, and the steps before flooring. That way the floor layer on a Soham plot knows exactly what base they are working on.
Anhydrite & Flow Screed prices in Soham
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 Soham
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 Soham
Soham is about 69.4 miles north-east of our Slough base as the crow flies, with postcodes including CB7. The nearest towns to it are Ely (5.7 miles), Newmarket (6.7 miles), Cambridge (12.8 miles) and Chatteris (15.1 miles).
More on anhydrite screed, part of our screeding services.
