I live an a terraced house built approx. 100-120 years ago and have a water problem underneath one of my bedroom window sills.
I will upload some photos later but here's a brief description of the problem:
As I said there is a damp patch under the window sill, about half a metre wide. This appeared last year, I have since gutted the room and had the walls rendered and plastered. I also had a new window installed at the same time. I must admit that the old window was in awfull nick and after inspection I had come to the conclusion that this was the cause of the damp problem. It is now obvious that this was not the case (the builder didn't advise me otherwise however).
Anyway. Today (first dry day in South Wales for quite a while) I have scraped all loose paint off the window sill, which I have found to be in bad condition. The best way of describing this would be a loose top layer of stone, almost as though water has penetrated beneath the top layer and caused it to seperate (in wood I would describe this as delaminating, though I don't think this would be the correct terminology for stone?). I have also removed the loose pieces of stone. I'll upload photos shortly.
Along with the above, beneath the paint I have unearthed a crack on either side of the sill, from front to back of the sill. Again I will upload photos shortly.
I am now under the impression that this (the cracks) is the source of the water ingress. Please could you offer your proffessional opinions on this problem. Any comments will be greatly appreciated.
In the meantime (as soon as I have typed this) the only thing I can think of to remedy this temporarily is to get the silicone sealant out and go to town (I am desperate to save the nice new plastered wall inside).
Right! I'm off to play with the sill again.