Tracing a Dining Room Damp Patch to a Gutter Fault in Battersea, SW11
An isolated damp patch on a dining room wall in Battersea was traced from the flat roof above to a displaced gutter end cap and worn pointing. The fix was a targeted repair, not damp proofing.
Project at a Glance
The Brief
The owner had a single damp patch on a dining room wall and wanted to know what was causing it before committing to any work.
The Survey
To find the source, our surveyor started the inspection on top of the dining room flat roof. The end cap from the main roof gutter had been displaced, so rainwater was spilling straight onto the wall above the damp area. The pointing below had worn away and moss had built up on the coping.
Moisture readings were high only within the affected patch, up to 62.9% on the WME scale, while the wall around it read dry. Thermal imaging showed a matching cold spot caused by moisture evaporating from the wall. There was no evidence of rising damp or of a wider problem.
The Solution
The answer was to stop the water at its source and repair the damage it had caused.
- Rake out the worn pointing outside and repoint the affected area.
- Remove the damp plasterboard inside, replace it and finish with a skim coat.
- Refit the gutter end cap so roof water runs into the gutter instead of down the wall.
The Work
The internal and external repairs took two days, and the owner signed the job off with no unexpected issues.
The Result
A chemical damp proof course would not have helped here, because the water was coming from above, not below. That is why every job starts with a survey. Read more about penetrating damp or see our page on damp proofing in Battersea.
Frequently Asked Questions
Why is the damp only in one patch of my wall?
A single, well defined patch usually points to a specific source outside, such as a gutter, downpipe, flashing or a section of failed pointing, rather than rising damp.
Can a small gutter fault really cause damp inside?
Yes. A displaced end cap or leaking joint can pour water onto the same spot every time it rains, soaking through solid brick over time.
Do I need a damp proof course for penetrating damp?
No. Penetrating damp is fixed by stopping the water getting in and repairing the damage. A damp proof course only treats rising damp.
A damp patch that will not dry out?
Our CSSW and CSRT trained surveyors find the real cause before recommending any work. Non-invasive survey with a clear written report. No obligation.
Survey carried out by Lionel Sewell (FODCS) at Advanced Damp. Project completed in Battersea, SW11.
Sam Fitzgerald is the founder of Advanced Damp and a working damp and structural waterproofing surveyor diagnosing and treating moisture problems in residential and commercial properties across London and the South East. He is FODCS certified (a Federation of Damp Certified Surveyor) and a member of the Federation of Damp. His hands-on work covers rising damp, penetrating damp, condensation, basement waterproofing to BS 8102, and thermal imaging surveys, and he has personally completed over 400 damp surveys across properties of every type and age. Everything he writes draws directly from jobs he has carried out. He does not write about treatments, products or causes he has not dealt with first-hand in the field.
