Spent quite a bit of time looking for a ready-made solution. (a few years ago) Found an option that I "fell for," but when I received the quote from the local construction store, I backed out. Now I don't remember the quote in detail, and a new search has to be done to find the right one. The delivery time was 14 weeks, which meant that another "temporary solution" had to be devised. Since the area I was planning to cover wasn't that large, the shipping cost (about 15000kr?) and "start fee" (12000kr?) became a significant part of the cost. Started thinking if there were more areas that would work with the same solution, and that might be the case. In other words, the desire remains. I've started thinking about another solution. First, seek out a local company that can spray foam insulation. However, I have no expectation that the insulation will be effective, so the desire is to fill the valleys with foam (top and bottom). Then glue on several layers of PIR insulation (total thickness 250mm) to finish with gluing a flat sheet metal (1-1.5mm?) to create a sandwich construction as well as a protective/wear layer. How should the construction be rust-protected? - I don't know which metal would be suitable. The big advantage of constructing it myself is the possibility of getting it completely tailored to the need. Easier to make neat finishes, etc.