Our 1997 four-bed house is pretty warm and since buying it I've topped up the attic insulation with two extra layers of glasswool laid across each other making it toasty warm. In the exposed areas of the attic I must have around 450 - 500mm now.
However the middle of the attic (about 25%) is floored with T&G chipboard nailed down with ring shank nails, real barstewards to remove if you want to lift the boards. Under the boards is only one layer of glass wool, probably 100mm or whatever was standard at the time. I've got some spare glass wool left and wonder if it would be worth the effort of shifting all the old cases and cartons and lifting the boards to add the left over wool. How good is a thin layer of wool under chipboard as an insulator? I guess warm air must get trapped pretty effectively in the spaces between the joists?
However the middle of the attic (about 25%) is floored with T&G chipboard nailed down with ring shank nails, real barstewards to remove if you want to lift the boards. Under the boards is only one layer of glass wool, probably 100mm or whatever was standard at the time. I've got some spare glass wool left and wonder if it would be worth the effort of shifting all the old cases and cartons and lifting the boards to add the left over wool. How good is a thin layer of wool under chipboard as an insulator? I guess warm air must get trapped pretty effectively in the spaces between the joists?
