Lantern Project in the Founder’s Entrance (Part 5)

What lies beneath…

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.”

Lantern Project in the Founder’s Entrance (Part 4)

Work on the Founder’s Entrance lantern is in full swing. The internal plaster conservation works were completed last month, along with the conservation cleaning.  And Tobit Curteis Associates have given us the below update on the conservation paint treatments they have been working on.

The scheme of decorative plasterwork and polychromy in the entrance hall is among the finest of its period in the country. It was conserved for the first time at the turn of the millennium at which point it was found that, although the surfaces were extremely dirty, having lived through the Industrial Revolution, the condition of the plaster and paint work was generally very good. Cleaning and conservation revealed the decoration in all its richness and had a huge effect on the appearance of the hall as visitors enter the museum. Some 17 years later, the conservation survey showed the condition still to be generally very good although there had been additional accumulation of dust and dirt as well as some minor flaking and loss resulting from unstable environmental conditions.

The aim of the current conservation project therefore is to record and document the condition of the decoration and to carry out limited stabilisation, cleaning and retouching. The team of conservators, working with Tobit Curteis Associates, has now been working on the conservation of the polychromy for three weeks and the work is progressing well. Most of the treatment carried out by Tobit’ team in 1999 and 2000 has remained stable and the areas of more recent damage have responded well to treatment. The planned relighting of the entrance hall will further improve its appearance so that visitors can again experience the decorative scheme much as the architect originally intended.

Tobit Curteis Associates

Lantern Project in the Founder’s Entrance (Part 3)

Discoveries

Investigations into the lantern are well underway.  (Catch up with what has happened so far by reading Part 1 & 2.)

Specialist contractors Brown & Ralph have begun to look at the side windows of the lantern. After removing the glazing putty from one of the panes of glass, more information about the original intent has been revealed.

Original pane of glass removed

Each pane has a central section of etching, with a clear border around the edges. Over the years, as repairs have been done and panes replaced, the putty and paint lines have crept further inwards, making the clear border not visible.

Red dotted line showing original line

The glass will be removed and cleaned. And, as the glass is reset, the putty line will be restored so that the clear border will be visible again. Looking at the windows as a whole, it is possible to tell which panes have been replaced.  The ones with a rose tint are original.  As part of this project, we intend to replace the newer non-tinted glass with rose-tinted etched glass in order to return to the original aesthetic.

View of side windows showing difference between old rose-tinted panes and the later non-tinted panes

Keep an eye on the blog – we will keep you updated as the project progresses.

 

Lantern Project in the Founder’s Entrance (Part 2)

Atlantes and lantern side windows viewed from scaffold platform
Protection during installation of scaffolding

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.

Foam and plywood were used to protect the historic mosaic floor. Sculptures which could not be moved were boxed in.

Nearby objects were protected from potential knocking and additional dust fall.
During the scaffold construction, the balustrade, bannisters and floor were boarded. Boards underneath scaffold legs ensured the additional load to the floor was spread. The scaffolding was cleaned before coming into the building, and clean wood was used. There was an increased risk of dust ingress as the front door would have to be left open while materials were moved into the building, so additional dust protection was in place; plastic sheeting proved invaluable to minimise dust movement to surrounding galleries.
Up close
Scaffold platform aptly nicknamed ”The Ballroom”

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.

Interior condensation tray with pipe leading outside
Exterior pipes for condensation pipes

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!

Lantern Project in the Founder’s Entrance (Part 1)

Founder’s Entrance lantern

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.

Moving day for the sculptures

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.

Can you turn the heating up?

No.  Well, maybe.  It depends.

At the Fitzwilliam Museum, collections are kept in the best environment we can achieve, in order to prolong the lifespan of the objects and artworks; temperature is an aspect of museum management which not only is important for the comfort of visitors, but it also has a huge impact on the collections.

As the temperature remains low over the Winter months, we have to think carefully about how we heat the building.

Why might we pause before turning up the heating?  Bear with this brief physics lesson, if you can:

Increased temperature can affect a range a materials, including adhesives, metals and resins.  And, while it may not be visually obvious straight away, increasing temperature can increase the rate of deterioration of objects.

Temperature also has a direct impact on relative humidity (RH).  RH is the amount of moisture in the air in relation to the temperature, and is given as a percentage.  100% RH means that the air cannot hold any more moisture – this is when you would see water dripping down the walls!  The warmer the air, the more moisture it can hold; and if we were to turn up the heat in a room, the relative humidity would decrease causing the air to feel dry.

Organic materials, such as wood, contain water.  If the RH of the air is less than the moisture content in the object, then water will start to travel from the object to the air – this is when cracks can (literally) start to appear.

Panel painting which has curved as the wood reacts to the level of moisture in the air

So, if we turn the heating up, we have to introduce moisture into the air using a humidifier to keep the RH at the same level.  This will help prevent the objects drying out.

With older objects, there is often more evidence of the changing environments it has encountered, like this panel painting.  The wooden panel has curved as a reaction to the humidity levels around it.

At The Fitzwilliam Museum, we have the added complication of working in a Grade I building.  The Founders Building dates back to 1848, and there have been several additions since.  We have air handling units in some of the more modern galleries, which can control temperature and humidity.  But in the older galleries, we can only use heat to control the environment.

Environmental monitor measuring relative humidity and temperature

We have over 70 environmental monitors in the building, and they help us keep track of the environment in all the galleries and store rooms.

So, when we are asked if the heating can be turned up, we might say ‘yes’ but we have to do a bit of data analysis first.

Readings from an environmental monitor in Gallery I. It is showing the daily fluctuations in temperature and RH.