Darkened grout over a kitchen extension's underfloor heating
The property
A 1930s semi whose large rear kitchen extension has underfloor heating loops set in the screed beneath big floor tiles.
The problem
Since the extension was finished, the boiler had needed refilling every few days. One row of grout had darkened, and the owner dreaded retiling.
How we found it
Each loop was closed off and put on a gauge. The one serving the far end of the kitchen fell; once that loop was warm, the thermal camera showed a blot under the dark grout.
The outcome
Moisture readings at the grout agreed, so four tiles came up at the mark. The loop was joined and retested while we were there, quoted separately.