No 6. Ceiling Damp Stain - Is The Roof Leaking?
Damp stains seen from the underside of ceiling sheeting are a common defect on older homes.
Unfortunately, the causes of these stains may be difficult to establish during a Pre-Purchase Building Inspection especially if the stain is currently dry. When our inspector identifies a stain to the ceiling during the inspection he notes its position and uses either a moisture meter or a thermal imaging camera to establish if the area is currently wet or dry. If the area is wet at the time of the inspection, it is much easier to establish the cause (If it's raining and there is a roof leak for example) than if it's dry.
The causes of ceiling stains are many. Here is a list of some of them
- Broken Roof Tile
- Loose Roof Sheeting
- Dead Vermin
- Possum Urine
- Condensation In Roof Void
- Condensation on Under Side
- AC Unit Drain Blocked
- Water Plumbing Leak
- Loose Roof Sheets
- Insufficient Roof Sheet Laps
- Blocked Gutters
The inspector will attempt to get onto the roof and into the roof void to identify the cause of the stain however he can only do this if it is safe to do so and the areas are not obstructed. You will often see these stains in a report with a recommendation to investigate further because the it is not possible to fully identify the cause within the scope of a pre-purchase inspection. For example, it may be necessary to remove insulation from the roof void or install safety equipment to access a high or steeply pitched roof.
Another problem ABIS inspectors come across is venters will freshly paint over stains without address the cause. This can make it very difficult to pick up the issue especially if the roof void is obstructed with insulation, etc.
We have even come across situations where a vendor has used dust from a vacuum cleaner to cover up evidence of a leaking roof on the top side of a ceiling sheet.