Thanks, interesting product. Their shipping container insulation looks good too.

Declaring an interest: we're Build4less, a building materials supplier, so take this as general experience rather than a pitch.

Interesting brackets. Carrying the battens on a bracket instead of driving long screws through the insulation makes a lot of sense, and anything that cuts down on point thermal bridges and crushed insulation at the fixings is welcome.

One word of caution on pairing them with sprayed foam for IWI over here. UK lenders and surveyors have become very wary of spray foam, and plenty of sellers have had buyers' mortgages declined or delayed because of it, even where it was installed properly. RICS and the Property Care Association have both put out guidance, and many lenders now want a specific inspection report before they will lend. On a solid masonry wall there is also the moisture side: foam bonded to the wall makes it hard to inspect the masonry later and, depending on the type, can change how the wall dries.

If I liked the bracket idea for IWI, I'd be more inclined to pair it with a vapour open board such as wood fibre on a solid wall, or PIR with a properly taped VCL on a wall that is known to be dry, so the build up is easier to justify when the house is eventually sold.

In that (air sealing), and other things as well, Icynene has v similar properties to blown-in Warmcel - with obvious exceptions/eco credentials. Blown-in Warmcel is equally supreme at air sealing/gap filling, beating any kind of slab or roll insulation, significantly improving real-life insulation value to actually match its face value.

BTW, the brackets in the OP are called Insofast, not Isofast!

That's easy to prevent - just weave galv light garden wire criss-crossed in/out of the studs/sloping rafters @ 400c/cs, secured by occasional clout nails - gives the Warmcel something to grip strongly onto

Yes as always, but are you referring to the garden wire, or the brackets?

Posted By: build4lessThe problem over here is mostly perception rather than physics, because lenders and surveyors rarely distinguish between the types.

Yes, agreed. Although once in the walls and not visible, no surveyor will ever find it! Under sloping roofs is a completely different kettle of fish.

Posted By: build4lessalthough it's still something you'd be expected to disclose

"I have no idea what the stucture is".. Equally, last time I sold a house I'd built, the surveyor ignored everything I said!

Posted By: build4lesswith foam stuck to the underside of the felt or tiles is that nobody can check the rafters for rot or leaks any more.

And yet they don't worry about the same problems in walls.