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Basement Waterproofing with a Dual Sump Pump on Western Road, Tring HP23
A property on Western Road in Tring had a below ground area that needed to be made dry and usable. The solution was a full cavity drain membrane system with drainage and a dual sump pump.
Project at a Glance
The Brief
The owner wanted the below ground space waterproofed properly so it could be finished and used, rather than patched.
The Survey
The surveyor drew up a treatment plan for the below ground walls and floor, noting high external ground levels against the structure. Because water pressure against below ground walls cannot simply be blocked, the plan used a cavity drain approach that collects water and removes it.
Details on the plan included the footing to be dressed with mesh membrane, the window and reveals and the step to be brought into the system, and a dual pump system with a high level alarm discharging to a set point outside.
The Solution
A Type C cavity drain waterproofing system:
- Fix 8mm studded membrane to the walls and dress the footings with 3mm mesh membrane.
- Form a 100mm by 100mm channel in the floor, sealed with epoxy resin, to carry water to the sump.
- Install a dual sump pump system with a high level alarm.
- Fix plasterboard to the membrane by dot and dab and finish with a skim coat.
The Work
The membrane, plasterboard and skim were completed over four days. A planned ACO channel outside was omitted from the final scope.
The Result
The space now has a managed drainage system behind the new finishes, with a second pump and an alarm as backup. See our basement waterproofing page, or our page on damp proofing in Tring.
Frequently Asked Questions
What is a cavity drain membrane?
It is a studded plastic membrane fixed to below ground walls and floors. Water that gets through the structure runs behind it to a drainage channel instead of reaching the room.
Why fit two sump pumps?
A dual pump system gives a backup if one pump fails or the water volume is high, and the alarm warns you if the water level rises.
Can a waterproofed basement be plastered?
Yes. Plasterboard is fixed over the membrane and skimmed, giving a normal decorative finish.
Planning to use a below ground space?
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 Michael Young at Advanced Damp. Project completed in Tring, HP23.
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.
