Resolving Rising Damp to a Hallway on Bourne Avenue, SL4
A damp survey and remedial treatment to the hallway at a property on Bourne Avenue, addressing rising damp with plaster removal, DPC injection, salt neutralisation, and re-rendering.
Project at a Glance
The Brief
We were asked to attend a property on Bourne Avenue to carry out a full damp survey for the client. A damp survey was carried out by our surveyor, Robert Cain, to assess the property throughout, including the hallway, both bedrooms, and the external elevations, before any treatment was recommended.
Results of the Survey
The survey has indicated that there is a possibility of water penetration into the hall, mainly due to the lack of an adequate damp-proof membrane. Moisture measurements from the walls in the hall were consistently higher than acceptable levels, indicating a dampness problem that can cause structural damage and unsanitary living conditions if not repaired. Water stains were evident at low level, and because of the position at which the elevated moisture measurements have been recorded, there is a possibility of failing render.
Externally, the survey noted that adjoining roof, guttering, flashing, and downpipe areas needed checking to ensure they were not contributing to the damp concerns being reported, since these are all areas from which penetrating damp and water ingress could originate. Elsewhere in the property, the bedrooms showed separate issues relating to ventilation, insulation, and condensation, which were reported on and recommended for attention alongside the hallway works.
The Diagnosis
Because the elevated moisture readings in the hallway were concentrated at low to mid-level and consistent with a rising pattern, and given the water staining and render deterioration observed at the same height, the survey concluded that the most likely cause was rising damp linked to a damp proof course that was either absent, failing, or being bridged. This pointed to a defect at the base of the wall rather than a leak or condensation-related issue, since the pattern and location of the readings were consistent with capillary rise rather than a localised source above.
The Treatment Strategy
Based on the survey findings, we recommended a comprehensive damp proofing treatment to the hallway walls. The affected plaster needed to be carefully removed to a height of 2 metres to expose the base of the wall and any residual salt contamination. A new damp proof course was then recommended, installed using a Dryzone chemical DPC injected into the mortar course to create a barrier against further rising moisture. A waterproof render was suggested for the affected area after the installation of the DPC, together with a plaster skim, which would allow the wall surface to be returned to a smooth state.
This method was selected since it takes into account all factors regarding the problem of rising damp; the removal of the plaster is important because it eliminates the salt-infested material, which would further draw moisture in despite the presence of the new DPC.
The Treatment
Our contractor, Brandon Halson, completed the treatment over 2 days onsite. The scope of work followed the recommendations from the survey:
- Hacking off the affected plaster on the hallway walls
- Injectinga new chemical damp proof course into the base of the walls
- Carrying outsalt neutralisation treatment to the affected masonry
- Applyinga waterproof render to the treated area
- Skim plasteringthe walls ready for redecoration
No unexpected issues were encountered during the works, and the job was completed to the full scope agreed. The work area was left in a safe and tidy condition on completion.
The photographs below show the hallway walls following hack off, DPC injection, and re-rendering.
The Result
The rising damp affecting the hallway has been fully treated, with the new chemical DPC in place to stop further moisture rising through the base of the wall, and the salt-contaminated plaster removed and replaced with a waterproof render and skim finish. The scope of the work was confirmed as completed in full against the schedule of works agreed, and the job was signed off by our Head Contractor on completion.
As with all our damp-proofing treatments, redecoration of the treated area should not take place for several weeks, to allow the render and plaster to cure and the residual moisture in the wall to dry out fully. A breathable, water-based matt emulsion should be used, and non-porous wall coverings such as vinyl or lining paper should be avoided until drying is complete.
Why this approach matters: rising damp readings can sometimes be mistaken for a simpler, more superficial problem, but the pattern and height of the elevated readings in this hallway pointed clearly to a failing damp proof barrier. Treating the cause at the base of the wall, rather than simply redecorating over the water staining, is what gives the result long-term durability.
Damp Treatment FAQs
What is the test method for establishing whether there is rising damp or not in a given hallway?
A surveyor uses a moisture meter to measure moisture levels at various levels on the walls, and the result of rising damp will show high moisture levels mostly at lower levels with evidence of staining and damage to the render or plaster near the ground level.
What makes it necessary for removal of the plaster before installation of the new damp-proof course?
In cases where there is rising damp, the plaster may contain salts that absorb moisture from the air even after the cause of the damp has been fixed. This means that removal and replacement with waterproof render is necessary.
How long does it take for a wall to dry out after DPC injection and re-rendering?
Once a new damp proof course is installed, it stops further moisture entering the wall, but the residual moisture already in the wall will still need time to dry out, typically at a rate of around 1 inch per month depending on wall thickness.
Do you treat damp issues in other rooms as well as hallways?
Yes. Our surveys assess the whole property, and where issues such as condensation, poor ventilation, or penetrating damp are identified in other rooms, these are reported on with separate recommendations alongside any rising damp treatment.
Do you carry out damp surveys and treatment across Berkshire?
Yes. We carry out damp surveys and remedial treatment across Berkshire and the wider South East. You can read more on our damp proofing page.
Planning a Damp Survey or Dealing with a Damp Problem?
Our surveyors diagnose the real cause of damp before recommending treatment, using moisture readings and a full property inspection rather than guesswork. The survey fee is deducted from the cost of work if you go ahead.
Survey carried out by Robert Cain, damp surveyor at Advanced Damp. Treatment completed by Brandon Halson. Project completed at 69 Bourne Avenue, SL4 3JR.
Sam Fitzgerald is the founder of Advanced Damp and a working damp and structural waterproofing surveyor with over 12 years of experience 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.
