Museum of Natural History Roof Project

An extensive 26 month project to repair and clean the 150 year old glass roof covering Oxford University’s neo-Gothic Museum of Natural History, and to conserve the decorated timber and ornate metal work was completed for the scheduled re-opening of the Museum on Saturday 15 February 2014.

The project

Since opening in 1860, the 8500 tile glass roof had been prone to leaks, resulting in the ongoing challenge of protecting exhibits from damage and visitors from the nuisance of buckets strategically placed around the building to catch wayward drips.

The roof was designed to shine daylight onto the Museum’s ornate filigree ironwork, depicting intricate examples of flora and fauna. Sadly a century and a half’s worth of dirt meant that the tiles were no longer letting in as much light.

In the Museum’s 150th anniversary year, a £2.1 million project to clean, repair and conserve the glass roof, timber and ironwork was identified. Funding came from the University’s Repairs and Maintenance budget, together with additional donations made specifically for conservation of the timber and metal work.

The University worked on the project with local construction contractor Beard, conservation architects Purcell and quantity surveyors Turner and Townsend.

The challenge   

The project was complex and required a scaffolding sub-contract of over £300k. It took nearly three months to erect an internal 18m high, safe working platform and waterproof deck.

Each of the 8500 tiles was carefully taken down, soaked and cleaned with a non-abrasive scourer to remove degraded UV film.  Around 20% of the 12-15mm thick tiles have been replaced, either because of damage, or to remove any modern Georgian wired tiles added over the years.

Finding suitable replacements proved a challenge for the project team. The first tiles were identical copies of the originals made in ceramic moulds and baked in a kiln. However the production process was slow and too costly.

The solution

The eventual solution was finding a supplier that could produce the tiles more cost effectively by laminating two sheets of thinner glass together. This process produced tiles of the thickness and opacity required – but much faster. 

The Museum was closed for 14 months whilst the most extensive work was undertaken. During this period the Museum took the opportunity to clean and re-hang some of the larger exhibits and to undertake a major programme of lighting improvements.

Over 2000 specialist magnetic fixings (made by the Ashmolean Museum team), designed to protect the building’s structure have been used to provide the cabling support for the new lighting. This includes colour changing of the iconic ironwork columns, feature lighting to mirror the original gas ring lighting system and the introduction of 80 specially manufactured globes for the cloisters.

Paul Goffin, Director of Estates, says: ‘This project presented us with the ideal opportunity to enhance the appearance of this Grade I listed building, and to ensure its continued use and enjoyment for members of the public, students and staff.

‘It’s an impressive achievement. The newly cleaned roof and new lighting helps to enhance the entire visitor experience and demonstrates the collaborative working of different teams across Estates Services.

‘And, to date, there’s not been a single leak.’ 

Published August 2015