Damp spots on walls usually come from a leaking pipe inside the wall, a failed seal around a shower or tub, condensation from humid air or cold pipes, water entering through a window or roof, or moisture coming through a basement foundation. Finding out which one is the cause decides whether you need a plumber or another kind of repair.
Plumbing Leaks Inside the Wall
Walls that hold water supply lines or drains are the most likely spots for a plumbing leak. A damp patch that stays wet all the time, or grows even when no one is using water, often means a supply line is leaking. A patch that gets wetter after showers or flushes may point to a drain or fixture seal.
Shower and Tub Seals
Cracked grout, missing caulk, or loose tiles can let water slip behind the wall each time someone showers. The damp spot often appears on the other side of the wall or on the ceiling below.
Condensation
In humid weather, cold water pipes can sweat, and moisture can build up on cool exterior walls. Bathrooms without good ventilation are especially prone to this. Condensation usually leaves damp spots that come and go with the weather and how the room is used.
Outside Water
If the spot shows up after rain, look at windows, siding, gutters, and the roof. Damp spots low on basement walls can come from groundwater pressing against the foundation.
To narrow it down, note when the spot appears and whether it changes with water use or weather. Checking the water meter with everything off can also help confirm a plumbing leak.
If the cause seems to be plumbing, a plumber can check the nearby pipes for leaks and fix it. If the moisture is from condensation, insulating cold pipes can be a simple fix. Call JPR Plumbing at (833) 603-1840.