Flat Roofs

Following appointment onto the Palace of Westminster MEPFS Framework, the Flat Roofs project was split into two phases.

The initial phase required a series of surveys to ascertain the condition and build up of the roofs to reliably inform the Client Design Team of the proposed works as part of their Stage 3 design. This phase also entailed the design of the temporary roof structure which spanned across 1500m2 of 18 roof spaces, situated above and around the House of Commons Chamber and Government Whips. Working with the scaffold engineers, the design was undertaken in a considerate approach in order to protect the building fabric by minimising the ties into a UNESCO World Heritage Site whilst additional factors of adequate lighting and sound protection to the Chamber itself which would impact the design of the scaffold.

The second phase focused on the construction works itself, from scaffold erection to the replacement of the roof fabric. With close stakeholder liaison, the scaffold roof was successfully erected over the various roof spaces, totalling over 27 miles in length. Upon completion, the existing roof fabric, comprised of an asphalt and screed build up ranging from 180 – 250mm, was sympathetically removed. The scaffold design allowed for mechanical means for the removal of approximately 500 tonnes worth of waste, which had to be transferred from the various areas and removed from the site. To maintain business as usual, we worked closely with the stakeholders to coordinate our works and ensure these were phased to maximise productivity whilst not disrupting the House activities and the occupants in the surrounding offices. Internal crash decks were consulted with stakeholders, with 3D mock-ups presented to provide access areas to occupants whilst allowing for the safe removal of roof lights and pavement lights, which were later replaced.

Following the strip out phase, the existing fabric was replaced, with a new asphalt and tapered insulation roof build up installed. Before this was carried out, we worked with the Fire Department on how the hot works element of the project would be safely and successfully undertaken. This included craning a two-tonne asphalt cooker onto the gantry, which would boost productivity and benefit the programme. Scaffold was struck in sections upon reaching waterproof status on the various asphalt roofs, allowing completion of the final roof finishes. To restore the roof to its original finish, concrete pavers and kerb pavers to match the historic design have been installed using an open joint pedestal system. As the roof finishes progressed, various replacements of M&E equipment and installation of new life safety features were required, such as safe access systems and emergency lighting.

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Knollys House
17 Addiscombe Road

020 8730 6200