Using foam offcuts for insulation?

Depending on how big the bits are, you could "embed" them in canned foam.

Handy in the garden. I have a couple of "tender" perennials that have survived the winter outdoors thanks to closed cell foam

Sounds like small bits, chuck 'em. If there are enough large bits of kingspan I guess you could "crazy pave" 'em into a space held together with low expansion expanindg foam. Shouldn't think you have enough "waste" to be really useful though, not unless there was something very awkward about the spaces you were insulating and didn't use the larger offcuts within that that job.

You can use it. IIRC loosefill gets around half the insulation value of solid. You might fix that by mixing in a little loosefill fibreglass insulation.

NT

Granulate it and then set it in expanding foam ;-)

But then if any water gets down there from roof leaks or plumbing leaks it would stay there and rot the timbers, but with rockwool and loose fill there'd be telltale black mould on the ceiling below.

I am experiemnting with vertical lines of plasterboard between the kingspan so any leaks will soak through and show up before rotting the timbers!¬

I am experimenting with vertical lines of plasterboard between the kingspan so any leaks will soak through and show up before rotting the timbers!¬

I'm using an Aldi garden shredder to granulate the kingspan offcuts (bought it years ago but never used it in the garden cos it seemed too puny) Now I've worked out its maximum input chunk size its working well.