In warmer summer months, condensation appears on the interior of a first floor bedroom external wall. The wall is solid masonry, south-west facing and contains 2 chimney flues – this is where the condensation seems to focus. Is this because the flue space causes that part of the wall to be much cooler? If I keep the bedroom door open to increase ventilation, the problem lessens. I am surprised by the lack of ventilation as the bedroom has an open fireplace – maybe the door needs to be open to create a through draft. Can you suggest an alternative solution as I don’t want to have to sleep with the bedroom door open if possible? The house is 120 yrs old and in a national park and is very exposed so any air bricks etc, recommended may cause a heating problem in winter due to the driving winds. Also, the other bedroom with 2 flues which is north west facing has no condensation.