Leanto shed in coastal area.
2 walls single block (end new)
1 wall existing old building part cob over part block/part stone
Other end timber and part glazed window
Floor existing concrete
New roof. ceiling joists (new) supporting modern (recycled) timber sheets - roofing quality, and with two layer felt covering
Under roof - polystyrene fitted between joists.
There is ventilation at roof level - air brick at end and soffit venting at olwer (open) side of pitch.
No heat - electrics not installed
This cold roof construction is suffering from excessive condensation. Is there any way this can be reduced?
ie applied coatings internally or externally to walls and concrete slab?