Penetrating damp around your windows is usually a problem with the window frame – typically, it is not property sealed or in the case of an old window, the sealant is no longer effective. In this case, you may be able to have the windows resealed to correct the problem and prevent future moisture from getting through. However, in severe cases, it might be necessary to completely replace the window. If the damp that has been caused by the moisture getting through a faulty window frame has caused serious damage to the internal or external walls, this may require you to have the affected parts of the wall replaced or replastered once the source of the damp has been dealt with.