For nearly two centuries, a persistent leak has plagued the grand country mansion of Kingston Lacy in Dorset. Year after year, moisture seeped into the roof, confounding experts who conducted numerous reports on the issue. However, the National Trust has now finally identified the root cause: a design flaw by the renowned master architect Sir Charles Barry.
The Architectural Oversight
Sir Charles Barry, best known for his work on the Houses of Parliament, was commissioned in 1835 to design a new cupola for the 17th-century country house. In an unusual decision, he designed the windows of the dome-shaped structure to be glazed 'inside out'. According to the National Trust, this was possibly done to make the cupola more visually appealing to visitors. However, this meant that the protective putty was placed on the inside of the glass instead of the outside.
Consequences of the Flaw
This design flaw caused moisture to leak in more easily, leading to rotting timber window frames, destroyed paintwork, and the need for regular maintenance over the years. Historical documents show that repair work was carried out on the cupola while the Bankes family owned the property, and since 1981, the National Trust has also undertaken multiple repair campaigns.
Identifying the Problem
After years of investigations, the team at the Grade I-listed property has pinpointed the exact source of the leak: the windows of the cupola, which were glazed inside out. The National Trust spokesman explained: 'What's changed is that detailed surveys, long-term monitoring and historic research now give us a clear understanding of what's really causing the leaks, which means we can now fix the problem once and for all.'
Planned Repairs
Work will take place in stages over the next year. The team will also investigate and repair defects in the leadwork around the base of the cupola, which is also allowing water to seep in. The current works are aimed at stopping this cycle of decay rather than repeatedly treating the symptoms. This comprehensive approach ensures that the historic mansion can be preserved for future generations.
