During the winter we have a humidity level of around 70% inside our house and have to have a dehumidifyer running during the day. If we get a sunny breezy day I can get it down to the low 60's and in the summer to the low 40's. We have no obvious damp in the house except two small patches on the livingroom wall. We have a damp proof course, central heating, cavity wall insulation and double glazing. We don't dry washing in the house, have an extractor in the kitchen and bathroom.
BUT we have a large void under our house of 4-5 feet and it is wet down there (it is lower than the ground level outside by 3-4 feet) so think this is where our problem is coming from.
Has anyone had similar problem that they've managed to resolve and can recommend any companies/techniques.