Al 1953 :
I have a garage with an old corrugated asbestos roof. The roof has a number
of small holes where the rain gets in. Also, a draught gets in through gaps
where the sheets overlap. Would expanding foam be suitable to plug these
gaps and holes?

I don't know but faced with the same problem I used clear silicone
sealant to good effect. It kept the rain out and it was inconspicuous.

--
Mike Barnes