Main-PRO have just completed a re-roofing and structural project to the WHSmith and former Santander branch in Selby, North Yorkshire.
Initially, the job was intended to be a straightforward roof upgrade; it involved stripping off the existing built up felt roofing, installing 120mm insulation and recovering using IKO’s roofing system which offers a 20 year guarantee.
However, after stripping off the original covering we discovered a major structural fault with the concrete beam and block roof structure. Significant sagging of the beams had occurred over time which resulted in a 70mm low point over a span of approximately 6m; this was serious enough for us to stop work on the roof whilst we requested for a structural engineer to carry out a detailed survey.
A temporary felt covering was applied to the roof whilst the survey and report was undertaken. The survey revealed structural movement of the roof beams as well as the first and second floors.
Our structural engineer provided 3 design options for the installation of steelwork to prevent any further movement of the roof and floors. These designs were then put forward to WHSmith for their consideration as the installation of major steelwork in the building would have an impact on their shop floor.
Once the design was agreed, we instructed our metalwork fabricators to manufacture the strengthening beams, posts, and splicing components. Whilst this was underway, we carried out underpinning work on the ground floor party wall foundations to accept the additional loadings.
The three steelwork installations (ground floor, first floor and roof) took place over three consecutive Sundays to avoid disruption to the retail outlet who are open Monday to Saturday. Main-PRO would like to thank WHSmith staff for their assistance in attending the branch on the three Sundays.
Once the steelwork was installed and all the necessary making good was undertaken we could then safely resume works on the roof which has now been insulated and fully recovered.