Reducing outdoor metal roof condensation

[Griffith4ever]

Built an open sided lean to car port (3 sides open) - thin metal roof - it rains underneath, as expected, on these winter mornings. I want to reduce it. I'm torn between:

https://www.amazon.co.uk/POLYNOR-PUR-heat-insulati...

Which I've never tried (roof is 4x4m) so the above should be enough

Or, 6mm ply screwed to the purlins underneath, creating an air pocket. Which I have done before, but on indoor sealed buildings.

[Baldy881]

Don't know if it would help, but at a previous property I lived at we had a large concrete sectional shed built, with 'anti-condensation' roof. All that was apparently, was some felt-like backed metal roof panels on the inside. I certainly don't recall dripping water from the roof, but the walls still got wet and the shed suffered condensation anyway. But at least it didn't drip down onto stuff. Can't imagine applying some suitable felt on the roof underside with spray adhesive would be a costly thing to try. And whether it would work or not for your structure I couldn't say. But that's my only experience of sheet metal roofing.

Edited by Baldy881 on Friday 13th November 12:43

[POIDH]

Any foam below will reduce likelihood of water condensing on the underside of the roof. So that would work - just look a mess.

As well as the open sides, what is the floor made of and could water / vapour be coming from there?

By the time you have faffed with foams and boards, might it be cheaper to just go with a different roof for a 4x4m space?

[Griffith4ever]

I just fitted ther roof this week so won't be changing that in a hurry ;-)

Stone floor, metal roof. That's it really. 3 sides open.

Spray kit , between the purlins and rafters, costs about the same as 5.5mm ply. Ply will be neater I guess.

Edited by Griffith4ever on Friday 13th November 14:20