CID Pro Tips / Roof & walls

My wall is damp or mouldy. What should I do?

By CID Home Repairs and Services · Published

Start here

Find and address the moisture source before repainting. Note whether the patch follows rain, plumbing use or condensation. Ventilate when safe, and arrange assessment for recurring or extensive damp, hidden leaks or contaminated water. Avoid disturbing a large mouldy area yourself.

When to get professional help

Keep away from wet electrical fittings, unstable finishes and sewage-contaminated areas. If mould exposure is affecting your health, seek medical advice as well as addressing the property problem.

What have you noticed?

These clues help explain the problem. They do not confirm its cause.

What you seeWhat to report
The patch grows after rainReport possible water entry through the building.
It is near a pipe or wet roomA plumbing leak may need investigation.
It accompanies condensationVentilation and indoor moisture may be contributing.

What you can do now

  1. Take dated photos and note whether the area is spreading. Do not drill or cut into the wall to locate a leak.
  2. Address visible leaks and dry clean, wet surfaces promptly where safe. Keep electrical appliances away from the damp area.
  3. Describe the symptoms before choosing waterproofing, painting or cleaning. Extensive damage or mould needs appropriate professional assessment.

Details that help us arrange the repair

  • The room, approximate affected area and how long it has been present.
  • Whether it changes after rain, showering or other water use.
  • Previous cleaning, waterproofing or painting and how soon it returned.

If you rent or live in a managed building, notify the owner or property manager and agree the arrangements before authorising work. Take photos only where it is safe; you can share them when CID follows up.

What affects the repair cost?

Ask for the cause and proposed repair sequence in writing. Leak repair, drying, damaged-material replacement and redecorating can be separate parts of the work.

Questions before you book

Will anti-mould paint solve it?

A coating does not fix the underlying water or moisture problem. Establish the cause before deciding on a finish.

Does every damp wall need waterproofing?

No. A leak, rainwater entry and condensation need different responses. An inspection helps select the appropriate work.

Sources and further reading

These guides cover initial checks and reporting, not a remote diagnosis. If there is immediate danger, move to safety and contact local emergency services. Do not wait for a website enquiry.

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