Background:
When KFC wanted to enter the ‘next chapter’ and appeal to a younger audience, not only did it require the adoption of new technology, menu items and branding but it also required a rollout facelift for their franchise of restaurants across the UK. This was the case for the KFC Derby Foresters store. Run by Gastronomy Food Ltd, the project saw the modernisation and enhancement of the restaurant while improving the functionality of the space to streamline guest experience.
While investing in the interior of the restaurant and updating the external signage, it made sense for the owners to also upgrade the exterior of the building. The previous roof had reached the end of its serviceable life and was badly in need of repair. The roof is a warm roof design.
The roof is a flat area with significant upstands to half of the space. However, due to the roof sloping from back to front the height of the upstands drops from 970mm in height to 940mm in height. There is also a step onto a small canopy roof area.
Roofing product choice:
The previous roof was a single ply membrane which had been repaired numerous times over the years using a variety of liquid products. One of the biggest issues on this project was the timeframe for the work. Each week the KFC store remained closed resulted in the company losing significant income and they had to have all works both internally and externally completed within a four-week timescale.
Working with the tight timescale meant there would be no time for a complete strip of the roof and the decision was made to overlay on the existing roof. The existing substrate and would act as the AVCL and primer with a recovery board fixed on top. Single ply was then chosen for the waterproofing membrane due to its practical, cost effective and efficient properties that would bring the timeframe down.
Installation challenges:
The roof space was covered with a lot of plant equipment which, due to the internal works, was all switched off. The first decision was to decide which plant equipment could be removed and which the roofing contractors would need to work around.
Once the equipment had been removed, Leicestershire Flat Roofing cleaned off the existing substrate and installed a 50mm PIR insulation foil-faced recovery board mechanically fixed into the decking. The roofing contractors then unrolled the Armourplan P membrane over the roof and fixed into place with IKOfix fasteners. The team would then roll the next strip of membrane over the roof ensuring the end laps are staggered before hot air welding the side laps with a hot gun. On areas where additional fastening was required the contractors installed additional fastening before covering with a 200mm wide strip of Armourplan which they hot air welded on both sides and ends.
The perimeter edges and upstands were battened down to sit level with the parapet coping before plywood was installed to the edges with the parapet tops. At the upstands and openings, the Armourplan membrane is secured into place with a toothed flatbar which was then waterproofed along with the upstand in Armourplan P. The membrane was then adhered to the upstand and parapets by first applying an adhesive to the substrate, applying the membrane up and over the upstand and parapet and then rolling the surface to remove all air pockets. The membrane was then mechanically fixed on the parapet tops in accordance with the wind uplift calculations.
External corners on the existing plant equipment were dressed by making a cut in the membrane in line with the vertical corner before hot air welding into place. A corner patch is then hot air welded into place over the raised section of the corner patches.
Due to the roof falling from back to front, a large box gutter is sited at one end of the roof. The gutter was rotten which had resulted in water running straight through it. The roofing contractors demolished the box gutter down to the brickwork and rebuilt the structure with new joists and furring strips to ensure there were falls down to the outlets. Leicestershire Flat Roofing than waterproofed the gutter in Armourplan P which was fully adhered to the surface and then completed with black UPVC fascia and soffits.
The contractor is a part of the AccuRoof Roofing Contractor (ARRC) scheme which enables them to install systems supplied by Accuroof. Contractors are only allowed to install their systems if they are trained by Accuroof in their products and are regularly assessed on the quality of their work by their technical team. This provides the client and main contractor with peace of mind on the quality of the work.
Time was of the essence with this project so Leicestershire Flat Roofing, had to avoid a solution that would result in stripping the roof. Instead, the team, guided by the technical team at AccuRoof, opted for an overlay solution which would mechanically fix an insulating recovery board on top of the existing single ply roof. Choosing to install a single ply membrane like Armourplan P was then obvious for its speed of install and flexibility to work with the detailing on the roof. This included variable upstand heights, integration around retained plant equipment and the full reconstruction of a deteriorated box gutter.
The project not only extended the life of the building envelope but contributed to KFCs modernisation and rebranding efforts.
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