"Darren Cooper" wrote in message
...
Hello,

I have 4" roof joists and 4" of insulation in my loft and I want to make
it either 8" or 10" of insulation. Some of the loft is floor-boarded and
I'd like to floor more for storage etc, do I lay the extra 4" of
insulation in-between the joists and squeeze it in with the loft board or
is it not possible to board over the extra thick insulation?

Darren

There is stiff high performing foam insulation board about 2" thick. Use
this over the joists and have the chipboard over. The screws run through
both. Have this in the parts of the loft where boarding is needed. The
other parts, add Rockwool until 300 to 400mm deep.

Make sure all the holes into the loft are sealed. Pipes and wires. Fit an
insulated loft hatch that is sealed.