Rising Damp on a Shared Party Wall in Stockwell, SW9
Paint was peeling along a ground floor wall in an 1870s terrace in Stockwell. The wall backed onto a neighbouring courtyard, and a damp proof course installed many years earlier had failed.
Project at a Glance
The Brief
The owner had peeling paint along a ground floor wall that seemed to line up with a small courtyard in the house next door. A damp proof course had been installed in the wall many years before.
The Survey
The affected wall is a party wall shared with the neighbouring house, whose small open courtyard sits on the other side. The courtyard drain was not clearing properly, so water pooled against the base of the wall, and staining below the gutter and downpipe suggested rainwater was overflowing onto the brickwork. The painted courtyard wall was flaking and holding moisture.
Inside, readings along the hallway wall were well above normal, with blistering paint and salt contamination at low level. This was consistent with rising damp combined with moisture tracking through from the courtyard side, and the earlier damp proof course had deteriorated.
The Solution
Because part of the cause sat in the neighbouring property, the specification was in two stages, with a party wall agreement in place.
- First, the courtyard drainage and rainwater goods on the neighbouring side to be put right, so water no longer pools against the wall.
- Then the rising damp treatment in the hallway: skirting boards removed, salt contaminated plaster removed to 1.2 metres, a damp proof course injected into the mortar course, waterproof render applied and a smooth skim finish.
The Work
The internal work took a day and a half. The owner was advised to wait five to six weeks before redecorating, using a breathable paint, so the treated walls could cure fully.
The Result
Dealing with the courtyard water first means the new damp proof course is not fighting a constant supply of water from next door. Shared walls and small courtyards are common in the older terraces around Stockwell and Vauxhall. See our page on damp proofing in Vauxhall.
Frequently Asked Questions
Can damp come through from a neighbouring property?
Yes. A blocked drain, leaking downpipe or raised ground on the other side of a party wall can keep it wet. The survey looks at both sides so the cause is fixed, not just the symptoms.
Why wait before redecorating after damp proofing?
New render and plaster need time to cure. Waiting five to six weeks and using a breathable paint protects the finish and lets the wall dry properly.
Do damp proof courses fail over time?
They can. Older damp proof courses can deteriorate, or be bridged by later work, raised ground or render, which lets rising damp return.
Damp on a party wall?
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 Stockwell, SW9.
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.
