I got these for a project and didn't need as many as I got, so I have a few surplus. PIR is an excellent insulator, better than polystyrene, XPS etc. One side is a galvanised metal sheet, the other is plastic film. I think that they're designed for ducting and ventilation.

There is some damage on some sheets, especially around the corners where they've taken a knowck, could be filled I guess? The galvanised sheeting on one side could be useful for protection, though some of them are corroded. Or it could just be removed.

I've got a few available. Price is per panel. Pick up only in South Titirangi.