As with many conservation projects, new discoveries are made as work progresses.
The contractors for the lantern repairs, Brown & Ralph, have provided an explanation as to what happened when they looked below the surface. What was revealed showed why this project is so crucial for the future of this historic building:
“Having removed the original weather-proofing from the lantern, several areas of suspected decay to the timber structure beneath were identified. Upon further investigation, it was found that some timbers were rotten and the structure weakened in these areas. This is thought to be the result of long term minor water ingress.
“Once the areas were identified, the Museum’s Structural Engineer worked with carpenters from Brown & Ralph to design a repair to the timber structure. This involved propping critical load-bearing timbers, cutting out rotten timber, forming joints and ‘letting in’ of new timber.
“The repairs were all worked out individually to cause as little interference as possible but maintain maximum strength throughout the structure. B&R were able to carry out all the repairs employing traditional timber joints. The replacement timber (some with sections as large as 300mm x 150mm) was selected from a trusted saw mill and used slow grown Douglas Fir to mimic the timber used when constructed originally.
“As a result, the structure is back to full strength whilst maintaining the original aesthetics. It has since been re-boarded with similar Douglas Fir.”
The installation of scaffolding took several weeks. During this time, there was a great awareness of the potential risk to the historic interiors and the collections in surrounding galleries. There were several methods of protection in place, to minimise risk from physical damage (e.g. knocks, scratches), as well as dust.
Now the scaffolding is up, survey work has begun and it provides a rare opportunity to get up close and personal with the lantern interior. Not only do we need to establish the extent of any deterioration or damage to the building and its decorative interiors, but also if we can understand the causes.
For example, staining in the dust below the side windows indicates that there has been condensation or water ingress. Closer inspection of the internal timber reveals that there is a condensation tray at the base of the lantern side windows. This design originally allows for collected condensation to flow through an outlet pipe to the outside. It may be that the pipes have been blocked by insects, causing the tray to overflow. To stop this happening in the future, we need to confirm the cause and either make modifications to the design or ensure changes to the maintenance of the current pipework.
We are still at the early stages of the project, and so survey of the plasterwork and internal decoration are ongoing.
We shall keep you updated as the project progresses – watch this space!
The Fitzwilliam Museum is about to undertake a major building conservation project in the Founder’s Entrance. The focus will be on the lantern at the very top of the building.
The Founder’s building was first opened to the public in 1848 and the maintenance and preservation of the historic features is paramount. As a Grade 1 listed building, it is a priority to ensure it will remain resilient long into the future.
This project will look to address a variety of different aspects, including the replacement of some of the gutters and rain water pipes to prevent leaks. Repairs and replacement of some of the damaged curved glass and glazing compound (which holds the glass in place) will be done. Conservation work to the internal decorative plasterwork and balustrade will also be undertaken.
Work has already begun in preparation for the scaffold installation: the sculptures that usually sit on the first floor landing have been boxed up and put into storage for safekeeping.
From the end of April, a large scaffold platform will be installed across the whole of the Founder’s Entrance to allow access to the lantern. This will mean that the Entrance Hall will need to be closed to visitors for a few weeks. Once the scaffold is up and false ceiling put in, visitors will be able to visit the Hall once again.
This project will continue into early 2018. Please keep an eye on the Conservation and Collections Care blog for updates and photos.