The Grade I listed Chapel is perhaps the most iconic building in Cambridge sitting gracefully on the reaches on the River Cam. It is one of the largest chapels in the UK and has incontestably one of the world’s most beautiful examples of Fan Vaulting, executed in the 15th Century. It is home to the King’s College Choir and forms an integral part of college life whilst remaining a prevalent destination for thousands of visitors each year.

The award of the re-roofing project was consequently a prestigious one. It was a privilege to play a small part in extending the life of the building for further hundreds of years, and also to increase the environmental credentials of the building.

Project Nature
This project comprised of the refurbishment of the existing lead-roof using an intricate scaffolding system and leadwork techniques. Once removed, the lead roofing was smelted and re-dressed for re-application to the roof. The scaffolding protected the delicate fabric of the building, side chapels and the historic stained-glass windows.

Alongside these works, structural resin repairs were carried out to the oak roof trusses and the installation of PV Panels across the entire roof area completed this prestigious project.

Construction Methods and Features

• Leadwork, including smelting, sand casting sheets and reapplication to the roof.
• Resin structural wood repair.
• Temporary works design and execution of scaffolding
• Photovoltaic Array fixed with bespoke mounting arrangement and fixing points, to reduce their appearance

Constraints and Successes

• The scaffolding system was an exceptionally complex design, providing access to the whole building but without introducing pressure to the fragile structure. Months of intricate design work preceded its final installation which was essential to the execution and completion of the project.
• The delicate nature of the historic oak roofing structure meant any hot works within the vicinity had to be rigorously supervised. We installed a fire-protected Hot Works platform and utilised other tools such as thermal imaging, a 2-hour fire watch and extensive availability of fire extinguishers to provide protection to the sensitive dry timber roofing system.
• The installation of the photovoltaic panels required specialist detailing as they were fixed to lead, however we successfully installed the array, which will aid reduction on annual electricity demand of the College’s main site, aiding the proposal to decarbonise its operations by 2038.

Project Facts and Stats

• We placed 71.31% of orders with local (within 50mile radius) subcontractors.
• We erected and dismantled 400 tonnes of scaffolding.
• The quantity of lead used (excluding rainwater goods), is approximately 91 tonnes, or 992 rolls.
• The linear meterage of replacement sarking board totalled 19,800m.
• We installed 438 photovoltaic panels, generating a power output of 184kWh.

“As I have mentioned publicly a few times, I am so grateful to you and your team, Matthew, Philip, Toby, and many many others. Today I saw the final bits of the Chapel site being taken away – what a project to share and be proud of. That, and Spalding (retro) and Old Gardens (in the midst of COVID and so much asbestos etc) – you sit on top of a wonderful team of can-do people who work WITH the client to deliver – on time, to budget etc. I do hope King’s will soon again be working with Barnes.”
Philip Isaac, Bursar, King’s College