Hello, We are thinking of buying a loft apartment in an old (more than 100 years old) building. The apartments have been very nicely built, but in two places on the interior brick wall, there is white, crumbly, dust-like stuff collecting on the wall, and a lot of the brick and mortar from the wall has flaked off and fallen on the floor. Is this kind of thing fixable? Is it just going to continue to get worse destroy the structural integrity of the building? Thanks very much in advance for any advice.