Ok then my situation is, condensation in a loft which was re-tilled and felted 25 years ago, along with a fire wall added. No soffit boards, mid terrace, ie no end gable or boards for easy ventilation. Is there any benefit in fitting venting tiles if the felt isn't vapour permeable, or is a simple answer, but not ideal, to cut some of the felt to allow the moisture to escape? The other properties do not have any felt, so no issues.