UFH installation defects
Underfloor Heating Pipe Floating Up in Screed
Liquid screed is dense enough to lift poorly clipped pipe during the pour, leaving reduced cover that shows up as a hot stripe or a crack line once the heating runs.
Get your UFH fix-down checked before pouring
Name, phone, email — we'll reply the same working day with a fixed price.
Liquid screed flows around pipework rather than being compacted over it, which is part of why it gives such consistent cover — but it also means anything not firmly fixed down can move during the pour. Underfloor heating pipe is buoyant relative to wet screed, and if the clips or staples securing it aren't close enough together or robust enough, the pipe can lift toward the surface as the screed is placed.
The result is reduced cover over that section of pipe. Best case, it shows up as a slightly warmer stripe on the floor once the heating is commissioned. Worst case, thin cover cracks or the pipe becomes visible or damaged during later works like fixing skirting or drilling.
This is one of the reasons we insist on inspecting the UFH fix-down and doing a pressure test before any pour, and it's worth understanding what happens if a lift is discovered after the fact.
Why pipe floats during a pour
- Clips or staples spaced too far apart along the pipe run
- Clips not rated to hold pipe down against the density of liquid screed
- Pipe not adequately pressure-tested and monitored during the pour
- Screed placed too quickly or from too great a height in one spot
- Insulation board with a poor grip surface for the fixing method used
Cover depth reference
30mm over pipe
Minimum bonded cover
35–40mm over pipe
Minimum unbonded cover
300–500mm centres
Typical clip spacing
≥3 bar, monitored
Pre-pour pressure test
Signs of floated pipe after handover
| Sign | What it suggests |
|---|---|
| Warm stripe visible faster than surrounding floor | Reduced cover over that pipe run |
| Hairline crack tracking a straight line | Pipe close to the surface locally |
| Pipe visible when drilling for fixtures | Cover significantly less than spec |
| Uneven heat output across the room | Inconsistent cover across multiple runs |
Get your UFH fix-down checked before pouring
We'll inspect pipe fixing and run a pressure test before any screed goes down, and quote a repair if it's already happened.
We check clip spacing and pipe fixing before every pour, not after. It's a five-minute inspection that avoids a floor-up repair later.
— Exeter Liquid Screeders
UFH Pipe Floating — questions we get asked
Keep reading across the site
Get your UFH fix-down checked before pouring
We'll inspect pipe fixing and run a pressure test before any screed goes down, and quote a repair if it's already happened.