Major restoration work is taking place at the Middle Drawbridge of the Tower, which was created in 1834 to allow munitions to be brought into the basement along a buried tramway. This originally rising drawbridge has been in poor repair and in danger of falling down. To prevent this happening, Historic Royal Palaces, in conjunction with English Heritage appointed NDB Interiors to undertake a project to build and reinstate a new, strengthened, rising drawbridge.
Key to this project was ensuring that the exact dimensions and original construction were replicated. To do this, Terrain Surveys carried out a 3D laser scan survey of the original bridge before it was dismantled. All records have been kept as historical evidence and for verification purposes. To fortify the drawbridge, a steel skeleton was placed inside the structure and this was covered with unseasoned oak by specialist craftsmen. Terrain also produced accurate drawings and plans to set out grids, control points and datums for the carpenters to use.
Other specialist teams have also been required to ensure the new drawbridge is in keeping with the old, including stonework and antique joinery experts. NBD Interiors Managing Director, Paul Johnson, commented on the project: “The millimetre-accurate point cloud 3D scans and high quality specification drawings Terrain have supplied to capture this historic building have facilitated this project tremendously. Using Terrain’s laser scanner and techniques has saved us time, money and stress”.
The project, however, has not been without its challenges; heavy rain added complications, particularly since workshops were set up in adjacent moat, drained back in 1843 and re-flooded in early 2014! Despite the weather, the project is set to complete on time and budget by Easter and will prove a prime example of English Heritage restoration.
