THE National Trust may need as much as £3-million to repair Castle Drogo, its Edwin Lutyens house in the Teign Valley, after the recent rains and gales.
The trust has known for about five years that the castle was developing serious damp problems and has already had the place re-roofed.
But the onset of storms in the autumn caused water to pour in through the windows and furniture was damaged.
The leaks are being monitored, but repairs will need to be started before the full extent of the task has been established by the architects.
House steward Michael Thomson said: "I would not be surprised if it cost £3-million.'
Despite its solid appearance, the castle is vulnerable to damp, first because it does not have cavity walls and secondly because, as Mr Thomson said, 'Lutyens houses do tend to leak.'
He said Lutyens was regarded as a great designer but was now less esteemed as an architect and that waterproofing was seen as one of his weak spots.
The castle management is trying to decide a policy to raise the money it will need.
The trust will be asked to contribute as much as it can, as the house was its first twentieth-century acquisition, was voted seventh best twentieth-century building in the UK in the 'Independent' and has rising visitor figures, bucking the national trend.
English Heritage, the government's heritage body, may be approached for a grant.
The management may also ask the National Trust to launch a national appeal.
However, there are many other National Trust properties in as bad or worse a condition which will be competing for money.