I will openly admit that I know very little on this subject but hopefully someone can provide some good advice. My girlfriend's flat here in Germany was built underneath where the cellar area of the flats that she lives in. The main living space is a large (about 60sqm) rectangle with windows facing outside along one side towards a canal.
At one end of this room there is a large downspout that comes through the room to the canal and is used to pass rain water from the main gutters through into the canal. This was hidden from the room in what looked like an MDF box and as of last year we started getting problems with damp.
So the builders are in and luckily this is nothing we have to pay for as it's a part of the main house and therefore nothing we have to cover financially and when they took the surrounding box down there was a huge amount of damp, the pipe insulation was rotting and sodden and there was mould growing as well.
They have drilled holes in the exterior wall to dry it out, removed the cladding on the pipe and here's where I start to get worried. They plan on re-cladding and building some form of container around the pipe, but say that the only way to fix the damp problem is to put holes in the container that lead into the living space!
If the problem was one of heat difference between warm flat and cold pipe space this sounds like it will just leak cold air into the flat, ultimately leading to higher heating costs. So the question is, how should a problem such as this be fixed.
Any help would be greatly appreciated
I include some pictures of what we currently have: