Need a fan for my garden office - 4m x 5m space

[OM2]

I've got a 4m x 5m garden office newly built.
I'm getting mildew everywhere - it's been used to store some things that were damp.

I only have 2 windows at the front.
I want to get an extractor fan to make sure I don't have similar problems in future.

What do I get? A kitchen one for £20?

Thanks.

 

[Bosswhite]

What type of Heating do you have in your office, is it man enough for the job, what is the insulation like ?

 

[OM2]

i have oil panel heaters.
it's concrete blocks on the outside, breezeblocks on the inside, with insulation inbetween.
floor and roof insulated + damp prevention (or whatever it is called) has been made.

frustratingly, i got loads of mildew. all been cleaned now + i have been drying out the room daily with air fans - getting ready to paint onto fresh plaster.

any advice would be great.
thanks.

 

[foxhole]

Needs ventilation , air brick each end to get thru draft. A low wattage fan plugged into a timer could help to reduce damp . But nothing will prevent it if you use it as a drying room.

 

[OM2]

Needs ventilation , air brick each end to get thru draft. A low wattage fan plugged into a timer could help to reduce damp . But nothing will prevent it if you use it as a drying room.

OK... so having at each end, could be a problem.
if vents on one single wall, would that be OK?
say have an electric vent on one side and on the other just have a vent?
let me know what you think

thanks

 

[foxhole]

Fine

 

[OM2]

guys... i am STILL stuck in finding a suitable extractor fan
the ONLY ones i see are for bathrooms, ensuites and small cloakrooms
i can't find NOTHING else