Need to keep cavity bead in cavity during refurb

Franm

Registered User
Messages
74
Hi All,
I was wondering if anyone has any good suggestions re how to keep pumped cavity bead (polystyrene) in place while window openings and walls etc are being modified. The bead is the loose type and I fear that it will all flow out once the work starts.

Would drilling a few holes around say a window and pumping in expanding foam be an option. Or is this a bad idea? (from any point of view, chemical, structural etc).

Regards
Fran