Test for dampness by checking for visible or musty signs, then comparing the suspect area with a dry area of the same material using a moisture meter. This can identify possible excess moisture, but it cannot confirm the cause. Compare the pattern with the common causes of damp before deciding which specialist to contact.
Check for signs of damp
Inspect during dry weather and, where practical, again after rain. Look at:
- ceilings and wall-to-floor junctions
- walls around windows, showers and plumbing fixtures
- floors, skirting boards and accessible spaces beneath sinks
- areas behind furniture that can be moved safely
- surfaces for stains, bubbling paint, lifting wallpaper, mould or white crystalline deposits
- plaster, timber and skirting for warping or unusual softness
- rooms and cupboards for persistent musty smells
Note whether signs appear after rain, showering or water use. Old stains may remain after a leak has stopped, and mould or peeling paint alone does not identify the cause. Look for other clues that a water leak is causing mould rather than assuming the two are connected.
You may lightly check whether an intact surface feels unusually cool or damp. Do not touch mould, sewage-contaminated material or wet areas near electrical fittings. Do not open walls, lift fixed flooring or enter confined roof or subfloor spaces.
Use a moisture meter
Take several readings across the suspect area and compare them with an apparently dry area made from the same material. Follow the meter manufacturer’s instructions and select the correct material setting where available.
Pinless meters can check walls for moisture without making holes. Avoid inserting meter pins into finished walls because concealed cables or pipes may be present.
Record readings in a simple grid and compare like with like, such as plasterboard with plasterboard. Different materials and finishes respond differently, so do not treat the displayed number as a universal moisture percentage unless the manufacturer confirms that interpretation.
Metal, concealed pipes, foil insulation, salts, coatings and variations in material density may affect readings. A pattern of elevated readings is more useful than one high result, but it still cannot prove condensation, rising damp or a concealed leak.
If condensation is suspected, record room humidity and temperature at similar times over several days. Note the weather, ventilation, showering and cooking. If the pattern is concentrated in a bathroom, check which ventilation option best prevents mould. A single reading is not conclusive.
When to arrange an investigation
Seek professional investigation if elevated readings persist or spread, materials soften, staining returns, deterioration progresses or moisture appears after rain or water use.
If water is actively leaking, turn off the main water supply only if the valve is safely accessible. Keep away from wet electrical fittings, switches and appliances, and arrange urgent assistance. Do not disturb suspected asbestos-containing material or areas affected by sewage.
Plumbing leak tracing must adhere to AS/NZS 3500.1 (the national water supply standard governing pipe pressure testing and joint integrity) and AS 3740 (the national waterproofing standard for internal wet areas to protect framing and subfloors against moisture migration) under Building Commission NSW Contractor Licence 305428C and Qualified Supervisor oversight.
Fixed Today is the trusted local team Sydney households and strata managers have turned to for over 15 years for reliable leak detection. When you reach out, our team asks a couple of screening questions about your property's construction—such as whether you have double-brick walls, timber flooring over a crawl space, or a concrete slab, and whether dampness worsens after hot water use or rainfall—so our vehicle arrives stocked with acoustic microphones, tracer gas kits, thermal cameras, and pinless moisture meters. If results suggest a concealed plumbing leak, contact our leak detection team for professional investigation. We walk you through a clear task breakdown before diagnostic work begins, backed by fixed upfront pricing and a $0 call-out on approved work.