All
many thanks for the advice. My initial reaction was that the "interstitial condensation" was rubbish, but having looked into it I honestly think that it is the only explanation. Essentially, I believe that the Protectawall coating on the exterior of the house is like cladding the house...
There is a pozidry (positive pressure ventilation system) but to be honest we rarely use it. When looking at the property I now realise that it should have probably indicated some problem to me - but it just looked like an extractor outside the bathroom. Other than that - simply windows...
Hi
we bought a rendered Victorian property about 9 months ago and had a full building survey done on it, which showed up no damp problems (one minor incidence of penetrating damp - apparently being caused by a faulty repair on an old air brick but nothing to concern us).
After buying it...