The £95 million facelift should see the condemned Victorian wing demolished and new accommodation and facilities built in its place.
Townend is an 18th century building with a Victorian Italianate wing.
During the 19th century an additional three-storey Victorian wing was built, squaring off the existing buildings and creating a central courtyard.
Water has been pooling around the foundation and the Revolutionary War section is separating from the Victorian wing.
Emerging into the sunshine, we stood on a stone terrace roof forming part of the Victorian wing of the castle.
There are three 30-metre long Victorian wings on the eastern side of the barn, added to house cattle.
The building comprises the remains of a medieval hall, a single storyed cruck-built structure with two farms and a Victorian wing built up around it.
Various Victorian wings were removed and it left lots of holes.
It has 681 rooms, 380 of them in the Victorian wing.
This included the removal of the Victorian wing, and most of the Edwardian additions.