UFH Screed Installation: What You Need to Know Before Booking

Screeding over underfloor heating is one of the most common and most technical applications in the industry. Get it right and you have a fast, efficient heating system with a perfect floor. Get it wrong and you risk cracked screed, cold spots, and a flooring finish that fails within months. Here is everything you need to know before booking.

Which Screed Works Best with UFH?

Liquid screed — anhydrite or gyvlon — is the industry-recommended choice for underfloor heating. It flows around and under the pipes, eliminating air pockets that reduce heat transfer efficiency. Its higher thermal conductivity means the system responds faster. It can also be laid thinner: 25mm cover above the pipe versus 65–75mm for sand and cement floating screed. This reduces floor build-up and speeds up drying time.

Pipe Cover Depth

You must have a minimum of 25mm of screed cover above the top of the UFH pipe. This applies to both liquid and traditional screed. Insufficient cover leads to hot spots, cracking directly over pipe runs, and reduced heat distribution. Always confirm pipe heights with your UFH installer before agreeing screed specification. screeding.com works directly with UFH installers on every project to confirm the correct build-up before a single bag of screed is mixed.

Commissioning the UFH Before Floor Finishes

Before any floor finish is laid, the underfloor heating system must be commissioned — a process of gradually raising the water temperature over several days to drive residual moisture from the screed. This is mandatory for anhydrite screeds and best practice for all. Typically: wait 28 days after installation, then run the system at 25°C for 3 days, raise by 5°C per day up to maximum operating temperature, hold for 4 days, then reduce. Floor finishes can be laid once the screed moisture content is below 75% RH (or 0.5% CM for anhydrite).

Programme Implications

UFH screeding projects require careful programme planning. Allow 28 days minimum drying time after installation before commissioning. Allow a further 7–10 days for the commissioning cycle. Then allow for moisture testing before floor finishes. Total programme from pour to floor finish: 5–8 weeks depending on depth, temperature, and ventilation. screeding.com provides a written programme with every UFH screeding quote.

Planning a UFH screed project? Get an instant ballpark quote from screeding.com, or ring us to discuss the specification in detail.