Calcium sulphate grades for Berkhamsted apartments and plots
Look at the drawings for a Berkhamsted job and the calcium sulphate screed will carry a short code, CA-C25-F5 for example. Read them in three parts: CA for the calcium sulphate binder, then a C value for how much it resists crushing (compressive strength) and an F value for bending (flexural strength), each in N/mm2.
Of the three usual grades, CA-C20-F4 suits home floors with little traffic. Most houses, along with offices and apartments, take the CA-C25-F5 grade, and CA-C30-F6 is for harder-working floors. With 19% of Berkhamsted's homes in purpose-built blocks of flats, the middle grade is the one those apartment floors are meant to have.
New houses are the other place it turns up. Homes built since 2015 make up 6% of the town, and a new house may have a calcium sulphate screed over insulation and heating named on its drawings.
Because calcium sulphate hardly shrinks, big bays with only a handful of joints are possible. Where those joints go, particularly across doorways and between heating zones, is fixed before pour day.
Some drawings name an alpha hemihydrate product, picked to dry sooner or to go down thinner, and with those the manufacturer's sheet governs depth and drying times.
Here the focus is the material. For the pumping method and where flowing screeds suit ordinary homes, see our liquid screed page for Berkhamsted. Background reading is in our guide, anhydrite screed explained.
Before flooring goes onto Berkhamsted anhydrite
Pouring is not the end of it: a calcium sulphate floor goes through three stages before any covering.
First, the laitance. Curing leaves a soft, powdery film on top; when the floor is dry it gets sanded off and the dust vacuumed up. Adhesives laid over laitance can fail. We can carry out that sanding through our floor preparation service.
Second, moisture testing. A hygrometer reading shows whether the screed is ready for the covering you have picked. The reading matters more here than on a cement floor, because the makers of many coverings will accept less residual moisture in calcium sulphate. If pipes run through it, switching them on after about 7 days helps the drying along.
Third, priming. Use a primer formulated for calcium sulphate, and match it to whichever adhesive comes next.
Keep it out of anywhere that may get wet. Where a shower area or plant room is part of the plan, a cement based flowing screed takes its place. If the plot is in Amersham, see anhydrite flow screed in Amersham.
Anhydrite & Flow Screed prices in Berkhamsted
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 Berkhamsted
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 Berkhamsted
As the crow flies, our yard in Slough is about 16.3 miles from Berkhamsted, which lies to the north. Postcodes here include HP4, and Tring (4.3 miles), Hemel Hempstead (4.5 miles), Chesham (4.5 miles) and Amersham (6.2 miles) are close by.
More on anhydrite screed, part of our screeding services.