Grades and bays for Feltham's mixed schemes
In Hounslow, 37% of homes are purpose-built flats. In a Brentford or Feltham apartment, this material makes sense because it barely moves while curing, letting a whole flat go down in broad bays with hardly any joints, and it runs fully over acoustic mats and heating pipes.
The specification will give a designation. CA tells you the binder is calcium sulphate. The C figure is compressive strength and the F figure flexural strength, both in N/mm2, under the European standard for screed materials:
CA-C20-F4 suits domestic floors with light traffic. CA-C25-F5 is the all-round grade for most homes, flats and offices. CA-C30-F6 suits floors that take heavier use.
Whichever grade the engineer writes down is the one we pour; we never substitute a near match. Where a grade looks unsuited to a room, we query it with the engineer first. Occasionally an alpha hemihydrate product appears on the plans in its place, picked because it dries sooner or can go down thinner, and its own data sheet then sets the depth and drying.
Bay and joint lines are set with you ahead of the pour. They sit at doorways and where one heating zone meets the next, never across the middle of an open room. On a large mixed scheme, with homes above shops or offices, that planning is what keeps a big floor free of cracks. For the background, our guide to anhydrite screed explains the material, and the screed pumping service covers delivery and placing.
Laitance, testing and wet rooms in Hounslow flats
As this kind of floor dries, a fine, crumbly film called laitance comes to the top. Adhesives and compounds grip the skin rather than the screed, and floors fail that way months later. Once drying is far enough along, that skin is sanded away and the surface is sealed with a calcium sulphate primer.
Moisture needs checking with care. Flooring manufacturers often set a lower moisture limit for calcium sulphate than for cement, so a Brentford flat floor can look ready before it is. A hygrometer reading decides. With underfloor heating fitted, switching it on gently from about day 7 can usually hurry things up.
Some 11% of Hounslow's housing dates from 2015 or later. New blocks run to tight programmes, and the written drying and laitance notes we hand over help the flooring contractor plan.
One rule does not bend: no calcium sulphate in rooms that could get wet. In a Hounslow flat, a bathroom with a walk-in shower, a wet room or a plant room where a leak is possible should get a cement based flowing screed, or the hand-laid mix on our Hounslow sand and cement screed page.
Anhydrite & Flow Screed prices in Hounslow
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 Hounslow
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 Hounslow
Hounslow is about 13.3 miles east-south-east of our Slough base as the crow flies, with postcodes including TW8, W4, TW14 and TW13. The nearest towns to it are Richmond upon Thames (2.5 miles), Ealing (3.5 miles), Sunbury-on-Thames (4.7 miles) and Ashford (5.5 miles).
More on anhydrite screed, part of our screeding services.
