35-second explainer
Wet loft: leak or condensation?
A 35-second guide to damp lofts: record the timing, understand clues and gather evidence safely before choosing a repair.
Silent, with on-screen text. Press play when you are ready.
General guidance. A property-specific inspection may be needed.
Watch on its own page →Read the video transcript
Wet loft? Leak or condensation? A damp loft does not automatically mean your roof is leaking. Start with the pattern.
Cold mornings. Lots of droplets? Condensation can form when moist air meets a cold surface. The pattern is a clue. It is not proof.
After rain? Record the timing. Note when dampness appears and whether wind changes it. Rain entry and condensation can happen together.
Before you book a repair, record when the damp appears, take photos from a safe position and keep details of previous repairs. Do not climb onto the roof to investigate. An inspection may be needed to establish the cause.
Get a straight roofing answer. Use the roof problem checker at northeastroofanswers.co.uk. Need help with your property? Enquire directly with J&L Welch. General guidance, not a diagnosis.
What this means in practice
Heat loss, air leakage, vapour movement and ventilation must be designed together. Adding insulation without maintaining the intended air path—or assuming a breathable membrane solves every moisture risk—can move condensation into concealed parts of the roof.
What to check next
- Distinguish condensation from rain entry
- Check extract fans discharge outside
- Keep ventilation paths clear of insulation
When should you ask a roofer to inspect it?
Seek a build-up-specific assessment when condensation persists, timbers remain damp, insulation has been altered or a reroof changes a thermal element. Compliance is based on the complete construction and target U-value, not an insulation thickness copied from another roof.
Safety first: do not climb onto a roof without suitable access, training and protection. Keep clear of loose coverings, unstable ceilings and water near electrical fittings.
Would you like a property-specific answer?
Request an inspection and written quotation from J&L Welch.
No deposit is required. Payment is due on completion within seven days, with the agreed scope and price confirmed in writing.