Historic Stockport Property: Multi-Level Waterproofing Solution for Commercial Conversion
Historic Stockport Property: Multi-Level Waterproofing Solution for Commercial Conversion
Trace Basements were engaged to address waterproofing challenges in a historic Stockport commercial property being converted into a hair salon and cocktail bar. After initial work by another contractor proved inadequate for the complex multi-level below-ground structure, our team implemented a comprehensive cavity drainage waterproofing system. The project required specialised solutions to manage water ingress, control condensation in a high-humidity environment, and preserve the structural integrity while supporting the specific requirements of both businesses.
Multi-Level Implementation: Applied waterproofing solutions to a historic structure with below-ground elements across two floors, including areas extending beneath external paving.
Technical Soffit Design: Utilized XPS closed cell insulation with integrated drainage channels to effectively manage water ingress from above, meeting BS8102 requirements for advanced waterproofing.
Thermal Consideration: Positioned insulation above the cavity membrane to create a "warm" system, reducing condensation risk in the high-humidity salon environment.
Environmental Control: Installed a humidity-regulated ventilation system specifically designed for the salon's operational requirements.
An unloved historic commercial property at the heart of Stockport’s old town, was purchased by our clients Tom to create a hair salon and cocktail bar, across three floor levels.
A specialist heritage contractor was instructed to progress renovations, this including the installation of structural waterproofing at basement and also at ground floor level, this because external ground levels rose around the side and rear of the building. As a result, the structure was below ground across two storeys, and even extended partially out below cobbled paving behind the building, so is subject to rainfall and water from above.
A sub-contractor was instructed to progress the installation of an internal cavity drainage waterproofing system by the main contractor. The combination of multiple levels and soffits with water ingress from above, implied advanced design and detailing, and on this unfortunately the installing contractor fell short.
When concerns were raised this ultimately led to attendance by materials suppliers, who recommended Trace Basements, and that we take over the structural waterproofing on the scheme.
We priced the work and were then appointed.
Initial work following removal of the installed cavity membranes, was undertaken to consolidate the wall substrates. The structure had at some point, received a cementitious render, which was well adhered to the structure. Again at some point prior, areas of this render were mechanically removed, damaging the brickwork in the process, and leaving an 'open', dusty substrate.
This was repaired and consolidated with cementitious slurries, before moving onto the next steps.
A critical element of the work was the soffit area. BS8102 recognises inverted cavity membrane systems as ‘advanced waterproofing’ and requiring careful consideration.
Beneath the soffit we installed XPS closed cell insulation which will not absorb water and is suitable for use in damp environment. The XPS sheets include an integral slot drainage channel, so when installed with the slots facing upwards, they acted as a basic form of drainage to carry water to the perimeter wall.
We then installed cavity drainage membrane beneath, in a single sheet to ensure no joints/potential weak points, with membrane fully supported on ply timber laid to falls to ensure drainage.
In our design the insulation sits above the cavity membrane, meaning that the cavity membrane is encouraged to be ‘warm’, and condensation upon this is therefore discouraged, particularly important in a hair salon with significant vapour production. Our skilled joiners employed finishing ply to support the membrane, precisely cutting this so that it did not need to be concealed, preserving precious floor to ceiling height, and the ply has subsequently been varnished to provide part of the aesthetic within the salon.
All ground retaining structures incorporating waterproofingsystems require heating and ventilating to maintain a dry environment, and with the extent of hair drying/vapour here, it was always going to be an important aspect of the project. Trace designed and installed a humidity-controlled extract ventilation system, drawing air from each location within the salon.
Another consideration included the ground floor structure at salon level, which was formed in suspended timber, resulting in a requirement for isolation details to the perimeter, where timbers could otherwise bear into damp walls. Details were formed by resin fixing stainless steel threaded bar into the walls, sealing back around these with the internal membranes and then installing timber to the stainless threaded bar.
Below this floor there are two main areas, a full height basement with plant/equipment, storage and a W.C. to support the salon over, and then a separate sub-floor void. The sub-floor void was not initially accessible, but needed to be lined out with the Trace system to ensure continuity of protection and a dry environment throughout. We asked the main contractor to create an access hatch and we then lined out the space, creating valuable additional storage space for the premises.
All walls and floors area below ground were ultimately lined out and protected with cavity drainage membranes, drainage channels and a sump pump system, which we continue to maintain.
In closing we were extremely pleased to be able to play a small part in enabling the success of these businesses, and for such great clients. Another sucessful project.
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