Anhydrite grades for Gravesend apartments and new plots
Calcium sulphate screeds are coded under a European standard: C followed by the compressive strength, F by the flexural, both in N/mm2. Three grades cover the usual specifications. For light domestic traffic the grade is CA-C20-F4. CA-C25-F5 is what typical houses, apartments and offices need. CA-C30-F6 handles heavier wear. We pour exactly the grade the architect or engineer has specified, never a cheaper swap.
Alpha hemihydrate products stand apart from these. Specifiers turn to them when quicker drying or a shallower floor matters, and every one is laid to its maker's sheet for depth, drying and preparation.
For flats, low shrinkage is the main attraction. Big bays and few joints are possible, which often lets an entire apartment floor go down in one pour. It goes over insulation and acoustic layers, or onto concrete, and it flows fully around underfloor heating pipes. We plan the bay and joint layout in advance, especially at doorways between flats and corridors.
Newer plots are a smaller share: homes built between 2000 and 2014, a period that includes the rebuilding of Christianfields between 2007 and 2013, make up 9% of Gravesend's stock. For the pumping and access side of a pour, see our Gravesend liquid screed page, and for a fuller explanation of the material, read what anhydrite screed is.
Laitance and moisture checks on Gravesend anhydrite floors
Laitance, a thin and weak top skin, appears on calcium sulphate as it cures. It must be sanded off once the screed is dry, because adhesives and compounds laid over it can fail along with it. The step is easy to miss on a busy site, which is why we hand over laitance advice in writing.
Moisture is the second check. The moisture limit flooring makers give for calcium sulphate is often below the cement figure. Use a hygrometer and check the result against the flooring maker's limit; a count of weeks proves nothing. Heating, where fitted, can normally start pulling moisture out from about 7 days.
Then the primer. It must be compatible with calcium sulphate and applied to a clean, sanded, dry surface. If the finish needs a smoother base, our levelling service in Gravesend can follow on.
Calcium sulphate is not for anything that may get wet. Wet rooms and anywhere that gets washed down should have a cement flowing screed or a cement screed laid by hand instead. Our screed repairs service covers damaged areas on either type.
Anhydrite & Flow Screed prices in Gravesend
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 Gravesend
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 Gravesend
Gravesend is about 44.2 miles east of our Slough base as the crow flies, with postcodes including DA11 and DA12. The nearest towns to it are Northfleet (1 miles), Tilbury (1.3 miles), Grays (3.2 miles) and Swanscombe (3.7 miles).
More on anhydrite screed, part of our screeding services.
