D.M. Procida wrote:
This may turn out to be a stupid question, but I have nothing to
prove...

I don't understand why it isn't possible to make roofs cheaply, using
board materials instead of tiles or glass fibre. It's possible to make
boats waterproof, with appropriate sealing materials and pain, so why
not roofs, which have to deal with a lot less water?

It would be convenient and cheap to put large plywood boards on a roof,
make sure that there's some kind of overlap or flexible seal where their
edges meet, and finish them with thoroughly waterproof paint.

I'm assuming that I'm not a genius who has thought of something that has
never occurred to anyone else, and there is a reason why this isn't done
- what is it?

Daniele

One of the things that really hit me on a visit to Latvia was the number
of painted roofs. Mostly red. But I did not get to see what was under
the paint - maybe galvanised panels? (I think I could see seams on some
of them.) And many others had obvious corrugated sheets.

If the panels could be made full length (from ridge to gutter), it could
make sense. Even better if the sheet edges could be non-flat (like tiles
- with some waviness or shaped edges) so that there isn't a simple
overlap. But even then, one of the biggest problems is expansion and
contraction - over the temperature range of a typical roof I'd guess
that was pretty considerable.

--
Rod

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