Gary Finnie
Hi You need to get it inspected as soon as possible. There can be many reasons for the damp and it is sometimes not caused by what seems to be the most obvious reason. Some of the reasons for damp are roof issues, sealant around windows & doors, pointing, degraded timbers, soil above the DPM, damaged chimney stacks to name just a few. On inspection, there should be a process of elimination of causes dependant on where the damp is. A builder or damp specialist will be the best person to contact.
