How does water move behind a wall without showing on the paint?
Water moves down a wall cavity by gravity and sideways along the framing and insulation. It can wet the drywall from behind without reaching the surface, and it can stay in the cavity for a long time. The paint shows the damage only once the moisture has reached the face of the wall.
Drywall takes up water from behind and holds it in the gypsum core. The paper facing can look dry while the core is wet. A stain appears only where the water breaks through to the paint, which is usually below the highest point the water reached.
Insulation in a cavity can soak up water and release it slowly, and the framing can hold moisture in the wood. The crew reads the cavity at several heights, because water can move upward through wicking and then drop back down.
Is thermal imaging enough to find a leak?
No. Thermal imaging can show where a surface is cooler, which can suggest moisture, but it cannot confirm a leak alone. The crew uses imaging to narrow the area and then confirms each spot with a moisture meter. The leak itself is found by opening a small area, not by the image.
A thermal image shows surface temperature, and several things can change that temperature without a leak. A meter shows moisture content in the material, which is the measure the drying depends on. Using both together reduces the number of openings the crew has to make.
The homeowner can ask to see the imaging and the meter readings side by side. Each finding should have a reading behind it, and the crew explains what each reading means.
When is it worth opening a wall to look for a leak?
A wall is opened when the readings are high and stay high, when the source has not been found by other means, or when the water meter shows that water is still moving in the building. The opening is kept as small as possible, and it is explained before it is made.
Opening a wall without readings can cause unnecessary damage and can leave the source untouched. The crew starts with the least invasive checks and opens only when the readings give a reason. The first opening is often small, a hand-sized hole in a low part of the wall.
Once the leak is found, the crew shows the homeowner the pipe, the fitting or the joint, and records the location on the sketch. The plumber can then repair it without searching the wall.
What affects the cost of hidden leak detection?
The main factors are how many areas must be read, how large the damp zone is, how many openings are needed to find the source and how hard the source is to reach. Each job is priced after the walkthrough, and no price is quoted over the phone. The repair of the leak is a separate job.
A leak behind an accessible wall in a single room is a smaller job than one that runs through several rooms and under a slab. The number of openings and the amount of drying that follows both add to the cost.
The repair of the pipe or the roof is quoted separately by the trade the homeowner chooses. The crew's detection report is shared with that trade so the repair can be planned from the evidence.
What should I do if I think there is a hidden leak?
Check the water meter with every fixture off, look for damp or soft spots, and note where the damp is worst. Do not open walls or pull up flooring yourself. Call the number and tell the team whether the meter is moving and which area feels damp.
A water meter that is moving with everything turned off is a strong sign of a leak somewhere in the supply. Write down the reading and the time, then check it again after a few hours. That simple record helps the crew decide where to start.
Keep the area dry and ventilated, and move items away from the damp wall or floor. Photograph any stain before it changes, because the photographs show how the damage has moved.