loft insulation

longwalks1

am planning on boarding part of the loft out for storing christmas decorations etc and will be using 18mm T&G chipboards, layed straight over the joists and screwed down. There is some old insulation down already, should i remove it and fit new, thicker insulation, or just lay some over the top? Will only be part of the loft for now, until the rest is cleared out

Also, where the best place to buy insulation from? its only about 5sq M area i'll be doing first, and the rest in the new year once we've had a chance to clear it out

TheCyclingProgrammer

You won't be able to put thicker insulation underneath without compressing it. It should be 100mm up to the top of the joists.

Ideally you should raise the decking up high enough to allow for 270mm plus a ventilation gap. You can use something like LoftZone packs or loft legs for this.

Owain_Moneysaver

TheCyclingProgrammer wrote: »

You won't be able to put thicker insulation underneath without compressing it. It should be 100mm up to the top of the joists.

Ideally you should raise the decking up high enough to allow for 270mm plus a ventilation gap. You can use something like LoftZone packs or loft legs for this.

Agreed. .

patman99

You can get a loft insulation that is sandwiched between 2 layers of foil. I cannot remember the name, but do remember that when they used it on one TV show, they made mention that a 100mm layer of it was equivalent to a 300mm layer of conventional rockwool type insulation.

Might be worth a look.

silverwhistle

I put boards over the insulation and joists years ago. When I returned to my house after renting it out I improved it by putting down Celotex on top of these boards - patman99 is referring to it, I believe. Then I put loft boards again over the top for the area I wanted to use for storage. The rest of the loft I just put a generous layer of the normal stuff down. If I wanted to extend the storage area I could just buy another sheet and more boards.

phil24_7

Just remember that the joists are unlikely to be strong enough for much weight. So boarding it out and storing heavy or lots of stuff up there is asking for trouble. I would strengthen the joists first.