Musty Smell or Mould? Water Under the Floor

Mould needs moisture, and a persistent musty smell in one room is the smell of a wet floor void or a soaked screed. A slow leak from a pipe under the floor does not make a puddle you can see; it soaks the concrete or the earth beneath the boards, and the moisture rises into the room as damp air, mould on cold surfaces and, eventually, swollen or lifting flooring. By the time the smell is obvious the leak has usually been running for months.

Suspended timber floors in the Victorian and Edwardian houses across London are the classic case: a leaking pipe under the boards keeps the void wet, mould grows on the joists and skirting, and the boards cup and lift. In the solid-floor houses around Watford, Bushey and Harrow, a leak in the screed shows as a smell, dark grout, lifting laminate and a skirting board that feels damp. Kitchens and bathrooms add waste pipes and appliance connections to the list, and ground-floor flats add the possibility of a leak from a communal pipe beneath.

We identify the water first, because mains, heating and waste water each point to different pipework. A moisture meter maps how far the damp has spread; a thermal camera shows cool wet areas and warm heating runs; a borescope through a small hole lets us look into the void without lifting the floor. Acoustic listening and tracer gas then pinpoint the leak so only one section of floor comes up. You get a written report with the moisture readings, thermal images and photographs.

Where the leak has damaged the floor or the finishes, trace and access cover on most buildings policies is the route to finding it and reinstating what we open. Our report sets out the source and the extent of the damp so the claim can move. If the damp is rising or from outside rather than a pipe, we will tell you that straight away rather than sell you a repair you do not need.