Loft insulation verses boarding

penrhyn

B&Q also do these boarding legs,they call them loft stilts.

Loft Stilts, pack of 12 (4074212) £19.98


http://www.diy.com/diy/jsp/bq/templates/content_lookup.jsp?content=/content/bq_home_magazine/george1.jsp&menu=default

mostly_harmless

Cheaper (and probably stronger) option than the roof stilts is to buy a length of 2x3 or 2x2 and cut into 7" lengths. You then stand it up on the joist and screw in at 45 degrees with 60mm or so screws. You then lay the insulation around these and can lay the board over the top and screw it down to the top of the joists.

Edit: I'd let BG do the whole loft and then roll back their insulation, fix the stilts, put their insulation back and then add the boards.

ic

Radshire wrote: »

Thanks for the tip on the space board ic. I might just return the chipboard I bought from B&Q the other day and pop down to Wickes and buy this stuff instead.

The space board is laid above the joists (and a thin layer of insulation laid between the joists). Chipboard is then laid on top of the space board - the space board is not strong enough in its own right to handle people walking on it, so keep your chipboard. There are versions of this space board stuff available that are already have the chipboard attached. However, its more expensive than buying the two separately, and you'll actually get more strength if the joins are staggered so that they don't overlap between the space board and top layer of the chipboard. The big thing you must do is ensure that the edges of the space board and chipboard always align with a joist underneath. Its all in the instructions for the space board.

googler

Are people genuinely putting insulation in their loft to such a depth that an almost 20cm leg is required to offset boarding from the joists? If so, I'm gobsmacked

Surely insulation to the level of the joist, plus interlocked tongue/groove board secured right onto the joist removes the air gap around these legs or stilts and provides better insulation?

penrhyn

The recommended depth of insulation is 270 mm, or 10 inches.

Typically you can only get 100 mm or so to the top of the joists.

ic

googler wrote: »

Surely insulation to the level of the joist, plus interlocked tongue/groove board secured right onto the joist removes the air gap around these legs or stilts and provides better insulation?

Absolutely. The insulation works by the millions of tiny air pockets in the layer of insulation. The thicker the better - just like a woolly jumper! The layer of chipboard does nothing for holding in the heat. The old spec was the depth of the joists, generally four inches. Now the recommendation is to stick another six inches on top - including on top of the joists - so taking it to 10 inches total. As I described above, I removed insulation and replaced with space boards for a storage area - allowing me take some areas to 16 inches! Waste not want not...

Radshire

googler wrote: »

Are people genuinely putting insulation in their loft to such a depth that an almost 20cm leg is required to offset boarding from the joists? If so, I'm gobsmacked

Surely insulation to the level of the joist, plus interlocked tongue/groove board secured right onto the joist removes the air gap around these legs or stilts and provides better insulation?

If I'm understanding correctly:
The insulation roles are layed all around the stilts - thus meaning there is no gap around the stilts. In fact, it is the still air which provides the insulation (air is a poor conductor of heat) so as long as there is a good quantity of insulating material (keeping the tiny air pockets still) it's going to be warm. If you put insulation down and then squash it to allow you to screw space board to the joists, you'll destroy the insulating property of the insulate because you've removed the air.

Radshire

mostly_harmless wrote: »

Cheaper (and probably stronger) option than the roof stilts is to buy a length of 2x3 or 2x2 and cut into 7" lengths. You then stand it up on the joist and screw in at 45 degrees with 60mm or so screws. You then lay the insulation around these and can lay the board over the top and screw it down to the top of the joists.

Edit: I'd let BG do the whole loft and then roll back their insulation, fix the stilts, put their insulation back and then add the boards.

Thanks mostlyharmless.
What makes you think that 2x3 is going to be stronger than stilts? From what I can see, the stilts have a wider base to support weight and screw vertically down into the joists.
Agree that they would probably be cheaper - and I may just do this as I'm not planning on storing whole load of heavy items up in the loft....just as long as it can take my weight that's all I'm worries out.

Radshire

Good advice ListysDad.

I've just had a combi boiler installed and am pretty sure that there are no pipes in the loft any more.

Are there any alternatives to FreezeFree - it seems expensive for what it is.

googler

Radshire wrote: »

If I'm understanding correctly:
The insulation roles are layed all around the stilts - thus meaning there is no gap around the stilts. In fact, it is the still air which provides the insulation (air is a poor conductor of heat) so as long as there is a good quantity of insulating material (keeping the tiny air pockets still) it's going to be warm. If you put insulation down and then squash it to allow you to screw space board to the joists, you'll destroy the insulating property of the insulate because you've removed the air.

Well, in my case, there's already insulation to the level of the joists, and I've boarded over it. To my mind, that hasn't compressed it - it was only the depth of the joists anyway - and that should have the effect of -a- trapping the air in there and -b- preventing the air above the boarding from circulating around the top of the insulation.

This method means I can board almost out to the eaves; if I was boarding on stilts, due to the slope of the roof, I wouldn't be able to board out as far as this; and that would be a compromising factor. So all in all, I think I'm better off with the boarding at top of joist level....