rob oneill

Hi.
I need to build a spray booth in my new workshop. I dont have unlimited space so have set aside an area of 20' by 11.5'. Should this be big enough?
Also, never built anything like it before, needs to be strong enough to store things on the roof, whats best to make it from?

I believe downdraught is the way to go, whats the best way to achieve this, how large an extractor fan should I use? needs to be filtered before being expelled, what kind/size of filter will it be?

So many questions!!

Thanks, Rob.