Concrete prefab garage - cement fibre roof insulation

[mturbo23]

Hi I am planning to insulate my concrete prefab garage along with the roof using 20mm foil backed foam insulation boards. For the walls this is fine but the roof will be cement fibre big 6 corrugated sheeting.

Will I need to ventilate this somehow as there will be air gaps due to the ridges in the sheets? or would it be better to try and fill them with something like expanding foam so it is all sealed?

I don't want condensation to form in the gaps and cause issues.

Thanks

 

[freddiemercurystwin]

Really ....

//www.diynot.com/diy/threads/coroline-condensation-catastrophe.419555/

 

[mturbo23]

Yes!

I guess I will find out for myself then.

I will be running a dehumidifier in there anyway so I guess it should be ok