Hi guys just going to jup straight to the issue , ive recently built a grow box ( 1.2mx1.2mx1.8m) its nothing huge but should be plenty if area for my own personal. So it was built using double sheeted 12mm ply walls/roof/floor+ door with 50mm poly insulation between the sheets. Its very sturdy and well built. The issue im having is the area it is in is constructed with 100mm thick medium density concrete block only 1 skin and all walls are exposed to elements outside. The room its in is suffering quite bad condensation on some walls , the roof was insulated with the same 50mm insulation with a 50mm airgap between this and the original roof (tin) which is vented through from both sides. The room has about 4 airvents to try to combat this but ive not been successfull its being vented into another room via a 5" inline fan which is rated at about 170 i think ? The temp inside box is 25-27c @40 odd RH. Im beginning to think i may well have wasted shitloads of time and money doing this for no point as i refuse to do it in an area with considerable condensation for safety reasons. I also do not want to start running dehumidifiers etc as im paying too much on electricity as is , can anyone recommend anti condensation paint ? I really want to vent into the same room so it kills noise a bit. Someone please help im at my wits end. Also the area i live is considerably cold and wet about 60-70% of the time