A brown stain is normally a sign that water has passed through a brick wall or over timber.
Tooltip Tags: techniques
Detecting surface dampness
Dampness deep within a wall when there is no surface dampness
Measure heat loss
Heating system water pressure loss. Instruct heating engineer to trace the lost water pressure from the heating system, fixing any leaks.
Leak detectors. Leak detection is complex, time consuming and sometimes expensive, especially if the leak is thought to be in imbedded concrete. Instruct a specialist leak detecting company such as Leakbusters.net
Detecting dampness deep within a wall in radio frequency mode. Meters can’t differentiate moisture from other dense matter such as metal and concrete. They help trace damp in a normal, homogeneous wall. Readings below 300 REL indicate that a wall is dry below the surface, 999 REL is the limit. These meters are for scanning and profiling.
Use a laser thermometer to measure the temperature of cold walls.
Use a pressure gauge to test for leaks. Once you have repaired the leak, you should check that the pressure remains steady.