Prefab Garage Roof - Condensation

[001ben]

Hi All, Brand new to the forum and I am hoping for some good advice.

I purchased a new 6x6m prefab garage in 2018 and the roof drips in the winter onto my toys and tools. This year in particular has been bad and I'd like to prevent this before next years winter!

I'm wondering what I could cover the inside of the roof in to prevent the condensation from dripping. I'm thinking that I could screw some Kingspan foil backed insulation board onto the timbers across the whole roof , or should it be secured in between the wooden strips.

Is this a good idea or a bad idea? is there a better way?
Thanks

 

[Swwils]

Take the roof off, insulate, membrane, reapply the roof maintaining the air gap.

 

[oldbutnotdead]

Best would be as above. Easiest will be fix sheets to the underside of the timbers. Seal all the joints between the sheets, job jobbed (no warm air getting to the tin sheets so no condensation)