Insulating under lounge floor

[GB_Groundworks]

bit off topic for here but with energy prices going up faster than they can count their profits, i was thinking of insulating under our lounge floor at moment the cellar is underneath. so from lounge down we have laminate/insulated underlay/hardboard/floorboards/joists/cellar.

the cellar ceiling isn't boarded so i was going to stick some rockwoll between the joists then some kingspan underneath to hold it in. got loads of rockwool and kingspan left around on the site i'm on so its free just wondered if anyone had any opinions.

[Mikey_C]

a subject that was featured in a recent copy of Professional Builders Monthly, all be it not with a cellar underneath their and other suggestions I've seen were to use a net stapled on the joists or staple the rockwall to the joist itself. Don't know if putting the kingspan up would reduce airflow to much?

[danensis]

I'd be inclined to leave a 150mm gap at each end where the joists meet the walls.

On the other hand, if rising damp doesn't exist......

[Suggers]

Hey GBG - I'm in same boat - water table came up in that very wet winter - wos it 2003/4 ? - we tanked new cellar in 1991 with good old ronafix to the exact spec - no probs until that sodding winter. When that water table decides to rise, wow, she comes up. I think our cellar's like an inverted swimming pool. Had to quickly buy submersible pump - running 24/7 - even so, we had 2" of water all the time, sitting there, for months. Plaster fell off the walls. We have brilliant tide mark round cellar now. Still smells. Might even give the famous Simeon a call one day, and ask him to pop in, for his advice as to what we should do now.
It's called rockwool - we use it for acoustic solutions. Not sure about it's thermal capacity.
http://www.rockwool.co.uk/sw47799.asp
I'm going for trad method of celotex on the ceiling - expensive but proven.
Mind you, if you've got a bucketload of rockwool for nothing - stuff it in.......as much as you can.
All the best.

[lutonlagerlout]

75 mm celotex or 150 mm jablite is standard underfloor insulation now as specified by building control
LLL