Educational Resource
Mistakes to Avoid with Underfloor Heating
We've been called in to fix dozens of underfloor systems installed badly by others. These are the most common errors — and how to avoid them.
We've been called in to fix dozens of underfloor systems installed badly by others. These are the most common errors — and how to avoid them.
The unfortunate truth about underfloor heating: it's easy to install badly, and very expensive to fix once the slab is poured. Mistakes made on day one can haunt the system for 30 years.
1. No heat-loss calculation. Installer guesses at pipe spacing, system runs hot or cold, can't be balanced. 2. Pipes too far from the slab surface — heat takes hours to reach the floor. 3. Insufficient insulation under the slab — heat goes down into the ground. 4. Manifold sized wrong — system can't be balanced room-by-room. 5. Wrong floor finish over high-output zones — timber cracks, vinyl warps. 6. No commissioning records — boiler is never tuned to the system.
Skipping the heat-loss calculation. Without one, the installer guesses at pipe spacing — and the system can't be balanced. We refuse to quote without a heat-loss calculation, every time.
Sometimes. If the issue is commissioning, controls or balancing — yes, we can re-tune. If the pipework is wrong (too far from slab surface, wrong centres, no insulation under slab) — usually only a partial fix is possible without major demolition.
Ask for: a heat-loss calculation, named insurance, references on past installs, a fixed-fee quote (not 'cost plus'), and commissioning records at handover. If they can't provide these, walk away.