Retrofit a moisture barrier/insulation to tin roof?

[bealers]

Hi,

our new to us house had a badly leaking asbestos roofed detached double garage so as this space was/is to become my manshed/workshop and I urgently needed it to chuck all my stuff in, I paid a local guy to take the old roof off and fit tin roofing.

I'm now getting really bad condensation and from reading around I understand that this is an age-old problem with no magic solution.

So, given I've already paid for a new roof, what's my best option for a retrofit fix?

I've read about polythene barriers but these seem to need to be applied when the roofing is? I had thought Kingspan between the stanchions? But this sounds expensive and I'm not too fussed about the heat retention, I just want the coating of water off the inside.

What about spray on foam kits like this? Sounds like the prefect option. Is it? Anything I should consider?

Thanks

 

[bealers]

actually, that spray stuff is bloody expensive, given it's a large double garage it'll cost a fortune to use.

Going back to the Kingspan idea, if i fit between the stanchions and batton, assuming I try and make it a pretty good fit should I get rid of the internal condensation?

 

[catlad]

You can get kingspan in 2400x1200x25mm I would buy one sheet cut it to size and then stick it to the tin roof with a water proof mastic like stixall by everbuild and see how get on.

 

[craig melvin]

I know its too late but Ive been doing garage roofs in profiled sheets for a while now.

He should have quoted for anti-condensation sheets - the ones with the fleece backing,

so some material will need fixing to the underneath. maybe polystyrene?

Craig