A Return Visit to a Below Ground Garage on Alexandra Road, Epsom KT17
Advanced Damp had previously installed a cavity drain system in a below ground garage on Alexandra Road in Epsom. When a band of damp appeared further along one wall, we went back to find out why.
Project at a Glance
The Brief
Damp had tracked further along the right side below ground garage wall, beyond the area treated before.
The Survey
Inside, the earlier cavity drain system on both sides of the garage was still intact. The damp formed a horizontal band along the right wall, at a height closely matching the pathway level outside. It was isolated rather than across the whole wall, which suggested the previous treatment had not failed.
Outside, there were minor cracks between the perimeter wall and the paving on the front path, wider cracks at the side entrance step, and deteriorating pointing at the veranda corner. Close to two months of rain had likely tracked down through those cracks. Thermal imaging showed no heavy saturation within the wall.
The Solution
Seal the route in from above:
- Apply a waterproof concrete fillet seal at the wall and paving junction.
- Repoint the deteriorated joints.
- Monitor the wall through the next wet period.
The Work
The repointing and sealing work was completed in May 2026.
The Result
The fix was small and targeted because the survey showed the original system was still working. Read more about penetrating damp or see our south London damp proofing page.
Frequently Asked Questions
Does new damp mean my waterproofing has failed?
Not necessarily. Here the damp lined up with ground level outside and came from cracks above, not from the existing system.
What is a fillet seal?
A sloped bead of waterproof mortar at the junction between a wall and paving that sheds water away from the joint.
Why use thermal imaging?
It shows whether a wall is cold and saturated or just damp at the surface, which helps confirm the cause.
Damp come back after treatment?
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 Epsom, KT17.
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.
