Kings College – Wilkins Hall Re-Roofing & Conservation Works
Wilkins Hall underwent a series of repairs and conservation work and completed in December 2020.
Originally constructed between 1824 and 1828 to the designs of William Wilkins, the repair work ensured the continued lige of this magnificent Grade-I listed building within the grounds of King’s College in the centre of Cambridge.
The scaffolding and temporary roof had a 3 month build time, before we could complete a full inspection of the North side of the roof. We initially surveyed the works via a drone whilst the scaffolding was being erected. On closer inspection of the slates, deterioration of stone, roof back gutters and weathering. It was only once the full inspection had been completed that the true extent of the works required became apparent. Leading to extra work needing to be carried out and also highlighted the extent of the gutter repair work.
Wilkins is used as the main dining hall for the students and Dons, and remained open at all times. The works being carried out on the roof with an open room below, was challenging due to Health & Safety. We designed a ‘birdcage’ scaffold to span the room, allowing the safety for the students below to continued use of the building. We also boarded out all of the roof space with ply-wood to prevent any fall through. This also worked well for the specialist stained glass repair company who used the bird cage to remove and replace the leaded lights.
The roof was lined with diminishing roof tiles, the works initially was to replace 25% of the roof with Welsh slates from the same quarry as the originals. After the closer inspection, it was advised that the remaining 75% of the roofing would only have approximately 20 year lifespan before they would need to be replaced. Taking advice from Welsh slate, and given the time taken and cost to erect scaffolding it was agreed with the client that we would replace them all.
Given the 6 month lead time for Welsh Slate, they were extremely accommodating taking on the order and incorporating it with another slate order for Trinity college Belfast which also had a diminishing roof Meaning that the off cuts from Wilkins would work out for Trinity, therefore ensuring there was no waste.
This project was logistically challenging due to the various road closures around the centre of Cambridge, all deliveries needed to be on site before 9.30am. All materials from slate, led, stonework, timber and cleaning materials, had to be transported from the road outside Kings college, hoisted up a level, moved along the platform to another hoist, that lifted to various levels. The reverse for taking waste material down, including the old slates.
