The Grand Magazine, Fort George

Context

This architecturally important building is right on the coast in the northeast of Scotland. The building is now being used to house an armoury of weapons used at Culloden, the last battle on British soil.

Issue

The building, being a well designed gunpowder magazine, is reasonably dry inside but not quite dry enough for a collection of weaponry. Leather was starting to slowly deteriorate and small amounts of corrosion were forming on some of the metals. The collection had been isolated in a large glass enclosure but it was not known how well this was performing to protect the collection.

Intervention

A one year period of monitoring established that the environmental conditions inside the enclosure were less good than in the main part of the magazine. The building could not be adjusted to any great extent so a portable electric heating system, controlled by Meaco humidistats was installed. The relative humidity setpoint was gradually lowered until the conditions in most parts of the enclosure were consistently below 65% relative humidity. A Meaco wireless monitoring system ensured that conditions in each part of the display were quantifiable.

Outcome

The whole enclosure now provided a stable environment that should ensure the long term survival of the whole collection – metals, canvas and leather. There is some concern that the lower relative humidity will increase salt formation in and on the brick and masonry walls. This will be monitored and consideration given to some intervention on the walls.