On 19/12/2019 19:21, wrote:
On Thursday, 19 December 2019 18:39:11 UTC, harry wrote:
https://www.diy.com/departments/corr...1777689_BQ.prd

Looked at that stuff but it wants 5 degrees or 1 in 11.

I suspect it would work at 1 in 20, but whatever angle I would not just
rely on rafters and purlins, I'd put it on top of (say) 12 mm OSB. I
rent a stable where similar material (probably steeper than 1 in 11) is
sagging and in places cracking and leaking at just over 10 years.

One I built in Wickes own brand is sagging all over the place like a
sixteenth century roof after 25 years but still watertight. (To be fair
it was rated for 10 years).

As a cheapskate, I like the plastic coated steel panels which come in
various thicknesses. Just one example:

Ebay item 131415083347

But I don't believe a word of the tech details, it says galvanized in
one place and aluminium in another. The cheapest ones are mild steel,
plastic coated both sides, about half a millimetre thick. These
certainly work at your pitch. No insulation and noisy in rain, of course.