The window sealant on a few upstairs windows has rotted. This has allowed wind driven rain to enter and the window sill has warped as a result. Would a joiner be able to replace the sealant and window sills ? Would I have to get a damp expert in to check that the wall is ok ? I'm looking into getting cavity wall insulation and can't proceed until the damp problem is fixed. Would the insulation people need to see some sort certificate to prove the damp has been dealt with ?
Thanks
