The Coronet Theatre, Notting Hill Gate, London

The Coronet Theatre build in 1898 was to be completely refurbished. The roof construction was, a concrete deck with a Laid-To-Fall screed, waterproofed with asphalt that some 20 years before had been overlaid with a liquid applied reinforced coating.

Product brief:

A structural engineer’s report limited additional weight being added to the structure and as a listed building heights of parapet walls could not be altered. Proteus Waterproofing carried out a U-Value and condensation calculation which showed a severe condensation problem in the roof structure that had caused severe spalling of the concrete.

High Performance Waterproofing

The client’s requirement was to provide a minimum 20 year waterproofing system and turn the roofs into a usable space for rehearsals, roof plays and for other social gatherings. Therefore, the new roof system needed to be light weight, remove the condensation issue, provide waterproofing and needed to be fully trafficable with an aesthetic finish

Problem Solving

Our U-Value calculation showed a minimum 120mm insulation was required to bring the building up to current building guidelines, however this would mean the roof finish causing the parapet to be too low for safe roof use. Therefore, a further calculation was carried out which showed a minimum 70mm insulation would remove the condensation issue and be thin enough to comply with the parapet wall height.

Proteus Waterproofing designed an overlay system utilising the Proteus Pro-Therm Protection board, a bespoke PIR insulation board with a 6mm cement board fully bonded to it. Being bespoke the board could be made with 70mm insulation, total thickness 76mm. This was then waterproofed using Proteus Pro-BW® Plus, a liquid that is a cold applied fully reinforced balcony and terrace waterproofing system. Utilising this insulation board and the Proteus Pro-BW® Plus waterproofing, Proteus Waterproofing were able to meet all the client’s requirements. Remove the condensation issue, meet the limitations of a light weight overlay system, waterproof the roofs and achieve the aesthetic trafficable finish required.

High Performance Waterproofing

Proteus Pro-BW® Plus is a high performance, rapid curing protective waterproofing membrane for balconies and walkways making it ideal for refurbishment where structural movement has occurred. Proteus Pro-BW® Plus reduces installation time from days to hours. Suitable for a variety of external applications, it can be installed on concrete and asphalt for both communal and private balconies, walkways, staircases and pedestrian ramps. As it is a cold applied installation, the system meets health and safety criteria by minimising risk to both operatives and members of the public. Proteus Pro-BW® Plus is BBA Certified and manufactured in the UK.

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