DIY Doctor UK DIY Forums

hi, i have a ex single garage , its got a new flat roof the main door has been bricked up and there are no windows, it has a upvc side door,i use it for storage and tinkering...it is dry and in good condition...i have a 4" vent hole near the top in the middle just to allow a bit of air movement when door is closed for any length of time...i have just noticed that the wooden shelves i have on the opposite side to the door has a fine layer of mould patches developing, there is also a steel cabinet which is developing mould aswell....this only seems to be where the light is coming in from the door and not on the same shelving further up in the garage !! any ideas please....would it help if i fitted an extractor fan to the 4" vent hole i have?if so should the fan be pulling air into the garage or extracting air from the garage?thank you robert

I get the same in my new garage & it was my fault as all the beams & shelving was done in treated roofing wood & the 8x4 sheets on the roof was in untreated timber & that gets a black spot mold on the underside of the roof.