Reading a flow screed specification in Oakham
Calcium sulphate, often called anhydrite, is a different material from cement. Because shrinkage is so low, big bays need few joints, and the material works well over underfloor heating. Specifications give it a class, with C for compressive strength and F for flexural strength, each measured in N/mm2.
CA-C20-F4 is used for domestic floors with light traffic, such as a bedroom or a small extension. CA-C25-F5 suits the general run of homes, apartments and offices, while floors that take harder wear get CA-C30-F6. On an apartment scheme or a group of new plots, the grade usually comes from the engineer or the developer, and we pour to that grade rather than substituting something else.
Apartments are a modest part of the Oakham stock. Purpose-built blocks of flats hold 11% of the town's homes, with conversions adding only a few more. On an apartment floor, the low shrinkage and flat finish of calcium sulphate let a whole flat be poured with few joints.
Alpha hemihydrate products are a special case. People pick them when a quicker dry or a shallower floor is needed, and each one's data sheet sets its own thickness, drying and heating rules. If your specification names one, send it with the enquiry. The anhydrite screed guide covers the chemistry in more detail.
We plan the bay and joint layout before pouring, so doorways and heating zones line up.
Laitance, moisture tests and primers in Barleythorpe
As any calcium sulphate floor dries, a thin and weak skin builds up on top. This laitance needs sanding back before adhesive or levelling compound goes on, otherwise the finish laid over it can come loose. On new floors in Barleythorpe and anywhere else, this step is easy to forget when the programme is tight.
Moisture needs just as much care. Plenty of flooring makers are stricter about moisture in calcium sulphate than in cement screed, so a floor can feel dry underfoot and still fail the test. A hygrometer test against the flooring maker's own relative humidity limit is the check to rely on. From roughly 7 days the heating can normally go on to force the drying along.
The primer must be a product made for calcium sulphate. It goes on after sanding and before any levelling compound or tile adhesive. For thin compound over the finished screed, see levelling a flow screed floor.
Anywhere that gets wet is the wrong place for calcium sulphate. A shower floor, utility room or anywhere likely to get wet should use a cement based flowing screed instead, and we offer that where needed.
Anhydrite & Flow Screed prices in Oakham
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 Oakham
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 Oakham
As the crow flies, our yard in Slough is about 78.7 miles from Oakham, which lies to the north. Postcodes here include LE15, and Stamford (10.5 miles), Corby (12.6 miles), Market Harborough (15.5 miles) and Desborough (16.2 miles) are close by.
More on anhydrite screed, part of our screeding services.