Choosing a CA grade for South Woodham Ferrers projects
On a drawing, this screed shows up as a code like CA-C25-F5. Read CA as shorthand for a calcium sulphate binder. After them, the figure following C is the crushing strength and the one following F the bending strength, both measured in N/mm2 as the European screed standard sets out. For housing the choice is usually between three grades. A guest room or study that sees little wear could go down at CA-C20-F4. The everyday choice for houses, flats and offices is CA-C25-F5, and a floor expected to work harder moves up to CA-C30-F6.
On an extension without an engineer's specification, we recommend the grade from the use of the room and the covering planned. Where a thin section is unavoidable, or the floor has to dry quickly for a fixed handover, an alpha hemihydrate product may suit better; those follow their own product sheet for depth and drying, and we work to it. A heated kitchen extension finished in large tiles is a common case for a considered grade choice, since the floor must stay flat and dry out on time for the tiler.
Flats are the other application. Purpose-built blocks make up 13% of homes in the town, and refurbishing a flat floor over insulation or heating is a job where the low shrinkage of calcium sulphate helps, because large bays can be poured with few joints. Joints are still planned at thresholds and between heating zones before we pour, and our own team prepares the build-up. Our anhydrite screed guide goes further into how calcium sulphate behaves.
Finishing anhydrite floors in South Woodham Ferrers before flooring
Nothing should be glued to an anhydrite floor until its top has been dealt with. As it dries, fine particles rise and form laitance, a weak skin that adhesives and compounds cannot grip. Once dry, the floor is sanded to remove it and vacuumed, then primed with a product compatible with calcium sulphate.
Moisture is the next test. Flooring manufacturers are often stricter about damp in a calcium sulphate base than in a cement one, so an anhydrite floor can look done and still fail. A hygrometer reading settles the question, and counting days since the pour does not. If the floor has heating pipes in it, switching them on from around day 7 and turning them up step by step usually helps the drying along.
Anhydrite does not cope with getting wet, so keep it out of any room where water could end up on the floor. Utility rooms at risk of a leak, wet rooms and walk-in showers are therefore out, and those rooms take a pumped screed bound with cement, or a hand-laid traditional screed for South Woodham Ferrers bathrooms. Where a new anhydrite floor meets an older floor that is being kept, the two may finish at slightly different heights, and a thin latex screed can bring them to one level before the finish.
Anhydrite & Flow Screed prices in South Woodham Ferrers
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 South Woodham Ferrers
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 South Woodham Ferrers
On the map, South Woodham Ferrers sits east of Slough, about 55.1 miles from our base in a straight line (postcodes including CM3), next to Rayleigh (4.1 miles), Wickford (4.9 miles), Rochford (5.7 miles) and Maldon (6.5 miles).
More on anhydrite screed, part of our screeding services.
