Anhydrite grades for Rushden flats and houses
Anhydrite is specified by grade, not just by name. Take CA-C25-F5: it is a calcium sulphate screed rated at 25 for compressive strength and 5 for flexural strength, in N/mm2, under the European screed standard.
Three grades turn up most often on drawings: CA-C20-F4 for light domestic traffic, CA-C25-F5 in most houses, flats and offices, and CA-C30-F6 where use is heavier. Whether it is a new house or a whole block of flats, the engineer's specification fixes the grade, and we pump exactly that.
Now and again the specification asks for an alpha hemihydrate material rather than a standard grade. Those suit jobs where quicker drying or a slimmer section counts, and their own product sheet, not the standard grades, sets the depth and drying advice.
What makes calcium sulphate useful day to day is how little it shrinks. The bays can be big and the joints few, so an open flat floor or knocked-through ground floor goes down in a single pour. Where joints are needed at doorways or between heating circuits, the layout is decided before the pour.
Since 2000, 22% of Rushden's homes have been built, and newer houses and flats are where these grades appear on drawings. Our guide to anhydrite screed goes further into the material.
Preparing Rushden anhydrite floors for flooring
Pouring the floor is only half the job. While it dries, calcium sulphate develops a weak skin on top called laitance. Tile adhesive, levelling compound and flooring adhesive grip it poorly, so once the floor is dry it is sanded back to sound screed and primed with a primer made for calcium sulphate.
Moisture is the other test. Flooring makers often set the moisture limit lower for calcium sulphate than for cement screed, so a floor can feel dry to the touch and still fail. When the flooring goes down is settled by a hygrometer reading. If the flat or house has underfloor heating, running it from about 7 days can usually force dry the screed.
Wet areas are off limits for calcium sulphate. Bathrooms with walk-in showers, wet rooms and utility floors that could flood should be laid in a cement based flowing screed, or by hand in sand and cement screed for Rushden wet rooms. If the programme needs a cement floor that dries fast, see our quick drying screed. Where both materials sit in one flat, we set the levels together so the thresholds match.
Anhydrite & Flow Screed prices in Rushden
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 Rushden
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 Rushden
As the crow flies, our yard in Slough is about 52.5 miles from Rushden, which lies to the north. Postcodes here include NN10, and Wellingborough (4.1 miles), Raunds (4.6 miles), Burton Latimer (6 miles) and Kettering (9.3 miles) are close by.
More on anhydrite screed, part of our screeding services.
