Project of the month: Oxford University Museum of Natural History
A project to repair the leaking roof and refresh the interiors of the Oxford University Museum of Natural History has been completed by regional contractor Beard and architect Purcell.
The grade I listed building has been a tourist attraction and centre of learning since it first opened in 1860, and houses the University of Oxford’s scientific collections of zoological, entomological and geological specimens.
The Gothic Revival museum building is characterised by its three dramatic glass and cast iron roofs, four storeys high, which span the main exhibition quad.
Over the past 36 months, Beard has carried out an extensive restoration project to clean and repair the vaulted glass roof, with each of the 8,500 diamond-shaped glass panels removed, cleaned and resealed.
The roof has leaked from completion 150 years ago, despite many attempts to fix it. The problem is the inconsistent thickness of the sand-cast glass tiles, which were cast to a nominal thickness of 10mm, but actually ranged from 8-12mm. These were nailed to the timber batons in an overlapping design, which created gaps that water could penetrate.
The roof of the museum had leaked for 150 years. Beard used mastic silicone adhesive to seal the sand-cast glass tiles
An effective solution was devised using a mastic silicone adhesive which proved ideal for both adherence and accommodating the tolerance required for the rough surface texture of the sand-cast glass. This innovative solution is fully reversible and allows the glass tiles to move and the building to breathe while maintaining the original aesthetic.
In addition, the lead has been replaced on the ridge and hips of the three glass roofs and the slate roof has also been relaid around the roof’s perimeter, extending down to the adjoining Pitt Rivers Museum.
As well as the roof work, the museum interiors required extensive cleaning and conservation. During the works, graffiti was discovered on the timber beams of the roof, thought to have been daubed by the Victorian roof painters. As a gesture to this, the present day project team was honoured with a plaque in the roof.
“With a new lease of life, we hope the museum’s newly-restored glass-tiled roof will continue to be admired and enjoyed by many generations of visitors to come,” said Stephen French, Beard site manager for the project.