Protecting 300 years of history

Blenheim Palace is a Grade I-listed Building, a Registered Park and Garden, and a UNESCO World Heritage Site. Designed by Sir John Vanbrugh and Nicholas Hawksmoor and constructed between 1705 and 1722, the palace is a Baroque masterpiece and home to historic ceiling paintings by Sir James Thornhill and Louis Laguerre.

DIA is currently leading a £12 million project as architect, lead designer, Contract Administrator, and BR and CDM Principal Designer. Works will protect the Palace and its priceless artwork from damage and deterioration via a programme of re-roofing, facade conservation and repair, M&E upgrades and paintings conservation.

Climate resilience has been a key focus of the project. New ventilation details have been added throughout, every very lead detail reviewed, and where necessary re-detailed, to meet current standards. To achieve capacity for protection from a 1-in-500-year storm, with an additional 40% allowance for climate change, every gutter has been redesigned and rebuilt. This long-term approach aims to protect the building for the next 300 years. Welsh slate is being used alongside the original lead, which is being tested, melted down, and sandcast for reuse. Structural repairs are required, in metalwork or English oak, with only the significantly deteriorated sections replaced.

A visitor platform was integrated into the scaffolding during the project. Open from April 2025 to April 2026, this offered once-in-a-lifetime views over the palace and grounds. The platform was fully accessible, offered a 300-person capacity, served by two staircases and two lifts, and obtained building regulations approval. Through this feature, over 100,000 people have experienced Conservation in Action.

Work is due to be completed in October 2026. Read more about the project and find updates here..