Edward Lyttons once did this fantastic interpretation of a medieval castle for a twentieth century client, and for aesthetic reasons, the roof doesn’t slope, and therefore doesn’t drain the water properly, The water gets in, seeps into the stone, and starts rusting the iron structural frame.
Oops!
Castle Drogo’s medieval-style flat roof has been its Achilles heel. Lutyens had attempted to seal the roof using asphalt, a relatively new and untested material for the time, but it was prone to cracks caused as the temperature rose and fell. Before the building was even finished, it had begun to leak.
The flat roof is roughly equivalent to two international football pitches. A high-tech roof system, designed by Bauder is being installed. This two layer membrane is designed to cope with the extremes of temperature experienced on Dartmoor.
In order to lay the new waterproof system, 2,355 granite blocks weighing 680 tonnes have to be removed and then reinstated. This will involve moving and reassembling entire battlements and large sections of the castle walls.
We have also had to redesign the roof gullies to accommodate the heavy Dartmoor rainfall.
