When Anders and Tommy were over in July, I talked to them about doing our roof in corrugated metal.
I received an email from them a week ago and they gave me a price of 75,000kr. This is nearly three times what I had planned! I haven't yet spoken to them for details but obviously I can't proceed at that price.
I have talked to another builder, though, and have a potentially different solution. Currently, the roof is covered with two layers of tarpaper. It's pretty lightweight stuff, but there are much more robust versions of roof paper (in Swedish, takpapp). The high-quality versions have a 20 year guarantee.
I found a good website of a provider which shows takpapp in detail. (It's in Swedish but has lots of photos). It's a little specialised in that seams need to be glued using a heat source, but if done properly, it's solid and long-lasting. It's even approved for a 14º roof pitch like ours.
Another advantage of the paper is that it can be transported in rolls, and is overall simpler to move and handle than corrugated sheets. As I've posted before, being on an island makes transportation a significant part of any building decision.
So, you ask, how much for a takpapp roof? I should have a formal quote in a couple of days.