What is penetrating damp?
Penetrating damp is a catch-all phrase that covers the many defects that may affect the external fabric of a building. Explained like this should tell you that there are an equal number or ways to fix it, but there are actually many more as the repairs depend on the type and extent of the defect, the type of materials used, the type of building it is, and the site conditions.
How do you know if you have penetrating damp?
Simply put, you will have damp patches, staining on walls or ceilings or peeling wallpaper, usually a combination of all of them. These indicate that there is a failure of the external fabric that is allowing water ingress whether it is one of a dozen ways a chimney can fail, or another dozen ways a roof can leak or many more ways water can enter through the walls or around windows. None of these defects wil be solved by replastering inside.
How do you treat penetrating damp?
It depends on the causes. A solution could be to improve a weathering detail, clean out gutters, ventilate a chimney or repair slating etc. Penetrating damp isn't a defect on its own but often used by the damp proofing industry to enable them to offer just one solution - re-plaster over a waterproof membrane. You can probably tell how that will work out.
How much does it cost to treat penetrating damp?
Another frequently asked question which depends on what is causing it in the first place. If you get an answer to that question in terms of £ per m2, then it is not repairing it, only covering it up. There is no easy answer to the cost as the defects need to be inspected by someone with no treatments to sell.