Anti condensation box section roofing sheets, any good?

[nuzuki]

Im wondering if these do what they say they do. The seller said they only work in buildings with adequate ventilation which seems like a good get out clause maybe. Anyhow I was going to go with this stuff for a garage roof. The rafters and noggins are in place. I was going to put a dpm sheet inbetween the roof frame and the roofing sheets but not sure if this would ruin the anti condensation properties or enhance it.

Any thoughts?

Thankyou in advance

 

[^woody^]

Anti-condensation will be insulation of some sort, and it will work if properly designed and thick enough. And yes ventilation is also a factor rather than a get out clause.

You could do this yourself, but condensation in an unheated garage will always occur

 

[nuzuki]

Thanks for the advice Woody. If it helps to reduce the condensation then I think its worth it in the long run. I shall be storing old cars in there so if I can reduce the moisture it will be better. Its only an extra 100-200 for the anti condensation backing so I think i'll go for it as i'll only regret it 5years down the line if i dont.

I have read about the DIY foam backed sheets and it apparently needs to be 4mm or thicker foam for our climate. I bought some via ebay from germany and have it ready to add to another outbuilding using some contact adhesive. Although as a kid building airfix models and stuff I remember solvent based glue tended to melt through foam and polystyrene so will have to test a bit before I get going.