A 190-year-old leak at Kingston Lacy house has finally been traced to a design flaw in the cupola created by Sir Charles Barry, the architect of the Houses of Parliament.

Persistent Leak Finally Explained

For nearly two centuries, Kingston Lacy house, a magnificent country mansion, has been troubled by a persistent and perplexing leak. Despite numerous investigations and reports, the source of the moisture intrusion remained elusive, causing ongoing damage and requiring consistent maintenance.

The Design Flaw

The National Trust team responsible for the preservation of the Grade I-listed property has uncovered the root cause: a fundamental design flaw introduced by Sir Charles Barry. In 1835, Barry designed a new cupola for the 17th-century Kingston Lacy.

Glazing Error

Barry specified that the windows of the dome-shaped cupola be glazed ‘inside out’. The National Trust believes this was likely done to enhance the visual appeal of the cupola for visitors. By positioning the protective putty on the interior side of the glass, Barry inadvertently created a pathway for moisture to penetrate the window frames.

History of Repairs

Historical records show the Bankes family, previous owners of Kingston Lacy, undertook repair work on the cupola. Since the National Trust assumed responsibility in 1981, they have also implemented several repair campaigns, but these were largely palliative.

Comprehensive Restoration Project

The team’s detailed surveys, monitoring, and historical research pinpointed the exact source of the problem. The current repair project will be executed in phases over the next year, rectifying Barry’s glazing error and addressing defects in the leadwork surrounding the cupola’s base.

Long-Term Solution

A National Trust spokesperson emphasized that the analysis provides a clear understanding of the leak’s origins, enabling a definitive fix. The aim is to break the cycle of continuous decay and prevent future damage, safeguarding the long-term integrity of Kingston Lacy.

This project represents a significant investment in Britain’s architectural heritage, ensuring the cupola is restored to its former glory and preventing a recurrence of the long-standing leak.