Plaster remediation at Vaucluse House
For the next few weeks, the upper hall at Vaucluse House will look a bit like a Christo installation as we work to remediate plaster damage in Fitzwilliam’s room.
Fitzwilliam’s room, at the end of the upper hall, is located directly below the concrete turrets added to the roofline in 1917 by the trustees of Vaucluse House. These turrets match the original stone turrets erected by William Charles Wentworth, but being concrete, they haven’t survived nearly as well.
Last year, SLM undertook a major conservation project using traditional methods and techniques to repair damage to the turrets caused by structural weakness and movement. This project was a success – so much so that SLM was awarded a NSW Heritage Award in 2017. The repair work put a stop to the water seeping into the walls through cracks, sealing the building and ensuring the turrets will survive another hundred years. With the house now watertight, the internal walls have been given time to dry out.
The next stage of the project is to remediate the damage caused to the internal plasterwork by years of water seeping through, bringing corrosive salt with it. The cornice in Fitzwilliam’s room was starting to exfoliate, and the surface paint had peeled significantly as the salts pushed their way through the plaster.
The first step was to remove the collection from Fitzwilliam’s room – furniture, bed, bookshelves, rugs, etc - and store it safely for the duration of the project. Next, larger pieces of furniture that were too difficult to move were drop-sheeted, and a protective membrane installed to prevent dust spreading through the house.
The old plaster had to be removed, which proved difficult as it was up to 60mm in some places. Once this had been chipped off the walls, a coating of Westox cocoon was applied. This poultice is made from pharmaceutical grade paper and has a high porosity. Applied wet, the poultice releases water into the masonry, which causes salt to become a solution. As the poultice dries, it pulls the salt solution out of the walls, along with any remaining moisture. After two weeks, the poultice is removed, and the process repeated.
Finally, when the walls are thoroughly dry and salt-free, they can be re-plastered with a traditional lime plaster. The plaster will then be given time to dry, before sanding and re-painting. It’s a slow process, but one we want to get right to ensure the safety of the collection and the longevity of Vaucluse House.
More from Vaucluse House
Caught in the nick of time at Vaucluse HouseThursday 7 September 2017
After a couple of weeks of unusually strong winds through the valley at Vaucluse House, eagle-eyed staff yesterday afternoon spotted a hairline crack at the junction of a large, horizontal branch with the trunk of the established jacaranda tree in the service courtyard.