We have hit the stage in our new build in the past week where the house has been sealed to the weather with windows in and roof finished. Noticed yesterday after recent rain that while most of the walls are dry, there are some isolated wet patches on the west-facing walls. Also some damp in corner where wall meets floor. Spoke to the engineer and without seeing it he seemed to think that its not unusual and some waterproofer and lime in the render should prevent moisture coming through. The engineer is coming to take a look - do I have a problem to worry about?