Loft boarding

Mercenary Keyboard Warrior

Mercenary Keyboard Warrior

Mercenary Keyboard Warrior

Soldato
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4 Aug 2007
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Wilds of suffolk
Looking for options

new house has significant loft insulation, looks like about 250mm or so (so maybe its meeting current 270mm regs)

Which is great, but i need to start boarding the loft for storage space

I've seen two solutions, first is the stilts that you screw into the joists and then screw boards to the top of. Simple in that I don't need to disturb anything. But they are relatively expensive for some simple bits of plastic, and dont get superb reviews consistently

Second is even more expensive but its basically a system of frames (metal) that construct a grid that you then board into. Looks beter than the stilts and I am sure it is, but its quite seriously expensive for what it is.

So they are the off the shelf solutions. neither scoring highly on my performance per £ ometer

I've seen some suggestions that what you can do is buy rigid insulation which you lay across the joists (like the top up layer of insulation) and then you board over that with loft boards. Seems sensible and means I can relocate the removed insulation to the areas I will not use, keeping edge vents etc clear.

Are there any other options?

I was considering removing some insulation to get back to joist level and boarding over the top, so kind of old school, surely the board is quite a good insulator anyway so loss wouldn't be that great? Even if its short term to get through the next x months until I have time to do a better job

Last option was remove the insulation completely where I want to board, use solid insulation cut to tightly fit into the gaps between joists and board over that.

I am struggling a bit to come up with best solution thats not super expensive and maintains close to the current insulation level as a minimum.

Anyone got any ideas / advice?
 
I used plastic loft stilts after we had British Gas round to top up our insulation. They work well, and although they're not cheap, the rigid insulated board is far more expense from what I remember.

You just have to measure centres carefully when placing them, as if you make a mistake you'll potentially be unscrewing dozes of boards.

You also need to stagger the boards, avoid overhangs, etc. as these chipboards aren't strong on unsupported edges.

I was considering removing some insulation to get back to joist level and boarding over the top, so kind of old school, surely the board is quite a good insulator anyway so loss wouldn't be that great? Even if its short term to get through the next x months until I have time to do a better job
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The chipboard on its own is not a good insulator at all, unless you meant the type with insulating foam attached to it.
 
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The alternative to loft stilts is to overboard your joists with rigid PIR insulation boards and then create a floating floor with tongue and groove chipboard over that.

PIR is far far more thermally efficient than wool, so the depth needs to be a fraction of wool for the same value.
 
Jez said:
The alternative to loft stilts is to overboard your joists with rigid PIR insulation boards and then create a floating floor with tongue and groove chipboard over that.

PIR is far far more thermally efficient than wool, so the depth needs to be a fraction of wool for the same value.
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Thanks jez that was the last option I was looking at.
It seems quite highly recommended, and I think it works out cheaper than the stilts.
I just don't like the look of the stilts, they dont look great to me
And you seem to need gazillions of them
 
Jez said:
PIR is far far more thermally efficient than wool, so the depth needs to be a fraction of wool for the same value.
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That's true from a zero-based start position, but in terms of incremental costs, he already has wool insulation to a sufficient depth, so I'm wondering if it will be much more costly to use rigid Kingspan or something. When I looked into it I remember it being extremely expensive?
 
We have 400mm, but in areas where we wanted boarding, filled the joist gaps with insulation, and then used the insulation (polystyrene) backed boards on top of the joists.
 
I used loft stilts to do mine and it turned out great as far as i'm concerned. Only thing I found was not all joists are straight which obviously can throw things off a little.

I bought my stilts from Wickes, which worked out a fair bit cheaper then B&Q or others. Also worth noting that when buying chipboard it's substantially cheaper to buy the 2.4m length boards and have them cut down for free in B&Q instead of buying of 1.2m boards, which are only £1-2 cheaper than the 2.4m board.
 
Participant said:
That's true from a zero-based start position, but in terms of incremental costs, he already has wool insulation to a sufficient depth, so I'm wondering if it will be much more costly to use rigid Kingspan or something. When I looked into it I remember it being extremely expensive?
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Ive just bought an absolute ton of it for a 500sq ft extension which required 100mm PIR in the floor and 200mm PIR in the ceiling (madness!) :p

Yep, its expensive, but he might not need much thickness?


To be totally honest if it were me and my insulation was already in place and to regs, i wouldnt use the legs either. I'd just get some cheap timber and build my own legs. The total cost wouldnt be very high at all.
 
Jez said:
To be totally honest if it were me and my insulation was already in place and to regs, i wouldnt use the legs either. I'd just get some cheap timber and build my own legs. The total cost wouldnt be very high at all.
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I'm planning on flooring parts of my loft too.
Still trying to decide between the plastic stilts or making my own timber legs.
The problem with making timber legs is that you'll need to get some angle brackets or something to bolt them down whereas you can put screws through the plastic stilts straight into the joists.
 
I plan on just putting Celotex boards between the joists to the height of the joist plus 25mm battens i plan on fitting to allow for wires and water pipes so that brings me to 95mm gap. So will be using 90mm Celotex then putting loft boards ontop of the battens.
Im limted by the 70mm joists.

If i wanted to go deeper i would fill to the height of the joist then go over the joists with 100mm celotex and put the boards directly on top of this. Even Celotex says its load baring, enough for storage and light traffic.
 
Jez said:
Ive just bought an absolute ton of it for a 500sq ft extension which required 100mm PIR in the floor and 200mm PIR in the ceiling (madness!) :p

Yep, its expensive, but he might not need much thickness?


To be totally honest if it were me and my insulation was already in place and to regs, i wouldnt use the legs either. I'd just get some cheap timber and build my own legs. The total cost wouldnt be very high at all.
Click to expand...

I was looking at seconds solid insu and I am sure its cheaper than legs.
Yes I already have the rockwool but even so seems similar in total cost and if I use solid i can go even deeper in the areas I am not boarding.

I had dismissed the making own loft legs as a "bloody silly idea" but I keep getting drawn back to this. At the end of the day we are only talking short uprights here, once screwed into place cant see a big issue. Was thinking fence posts could be ideal, as relatively good surface area when trimmed to size, quite low density so not loads of weight.

Its not like I am going to be trampling on them daily, probably once a month max over their life. Will use the tongue and groove boards so the load will distribute.

I am still tempted to go diy loft legs :)
 
I was thinking, whilst it sounds tricky you could probably knock up a simple jig that allows you to drill 4 holes thought the wooden legs to act as starter and guide holes.
So you can do this on a semi industrial scale somewhere like on a patio and take the already started legs up to the loft for fixing. Where the light and conditions are going to be poor by comparison.
What width are roofing loft beams, about 75mm?
 
Had a friend who went the wood DIY route, ended up breaking his roof due to the extra weight of the wood he used. Fence posts a NO NO
 
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