Hi,

We have an old, heavy wood door, hollow in places. I can see the spaces on
by looking through the hole for the peep-hole. There are spaces on both
sides, plus up and down, and I think I could use that as an access.

Are there any insulation products available which I could spray into that
access hole?

Spray type foams, such as Mastercraft Insulating Foam, seem inappropriate,
since they expand when drying and might split the door.

Thanks!
Dugie