"Bert Coules" wrote in
o.uk:

If I could be bothered, and thought I'd be here for a few more years,
I'd either re-roof it in insulated box-section steel or try
anti-condensation paint, which I understand works by providing an
absorbent layer.

I'd not heard of anti-condensation paint, so thanks for the mention.
A friend's garage (sectional concrete with corrugated metal roof) is
plagued with this condensation problem: perhaps a specialist paint
would help. I'll investigate.

Bert


Painting the inderside of the roofing sheets with polyurethane foam might
be even more effective?

JakeD