I know this has been covered a thousand times but have just read a couple of things that made me wonder if I can do what I planned to....
Current loft done on a grant with rockwool to current regs for previous OAP owners ...no boarded storage area.
Want an easy solution ...so in central area I was going to remove cross-joist rockwool (put excess round edges so just increase depth in other areas), lay kingspan/celotex sheets across joists and then chipboard over top (again across joists).. screw into joists...(like space board or those insulated B&Q boarding panels -but with Kingspan/celotex seconds it would be cheaper than either of those)
My Qs are
Do I need to leave a ventilation gap between rockwool in joists and insulation board across? (just read something about that - if using batons to raise 'floor' level? - unless I misunderstood?)
My thinking - recommended depths ...270mmm rockwool or 175mm kingspan/similar
Joists are 145mm deep - so 145mm rockwool ( 53% of recommended amount) so use 47% of recommended kingspan depth so 82mm -but thought I'd go for 90-100mm.
Could I go for non-foiled Kingspan/celotex at that depth? Is the foil bit important for this?
Would it be strong enough - load is spread because of chipboard?
And just read something about kingspan/celotex losing their insulating properties over time???? Is that true?????
Current loft done on a grant with rockwool to current regs for previous OAP owners ...no boarded storage area.
Want an easy solution ...so in central area I was going to remove cross-joist rockwool (put excess round edges so just increase depth in other areas), lay kingspan/celotex sheets across joists and then chipboard over top (again across joists).. screw into joists...(like space board or those insulated B&Q boarding panels -but with Kingspan/celotex seconds it would be cheaper than either of those)
My Qs are
Do I need to leave a ventilation gap between rockwool in joists and insulation board across? (just read something about that - if using batons to raise 'floor' level? - unless I misunderstood?)
My thinking - recommended depths ...270mmm rockwool or 175mm kingspan/similar
Joists are 145mm deep - so 145mm rockwool ( 53% of recommended amount) so use 47% of recommended kingspan depth so 82mm -but thought I'd go for 90-100mm.
Could I go for non-foiled Kingspan/celotex at that depth? Is the foil bit important for this?
Would it be strong enough - load is spread because of chipboard?
And just read something about kingspan/celotex losing their insulating properties over time???? Is that true?????
