Loft Legs

Has anybody use ‘loft legs’. Have just bought an old house. Need to sheet the loft in order to fill it with crap from the previous loft. There is tons of insulation protruding above the level of the joists. I therefore need to raise the level of the joists. Some advocate running extra strips of timber along the length of the joists to build them up. Some have suggested loft legs which sit on top of joists which can then be sheeted on top of. Looks a bit dodgy to me but would be far quicker easier and cheaper.
http://www.loftleg.com/index.php?page=what_is_loftleg
if you want to know what I am talking about.

i fitted loft legs and they are rock solid – could jump up and down on the chipboard now and they wont move. I got a deal on them i think so price wise they worked out ok and they do what they say on the tin – very easy to fit once you work out your installation pattern.

Some advocated extra timber but we’re in a new build so skinny joists mean adding too much weight would be a problem for popping taped joints.

I’d recommend them.

Scotlandthedave where did you get yours?

I’ve used them. The only slight problem with them is when it comes to boarding over them afterwards. You cant use tongue and groove chipboard as the gaps are too big, unless you space them very close together which then costs a fortune.

I spaced mine on a 400mm grid pattern which prevents the use of chipboard TnG (330mm spacing) but i dont think I would’ve trusted the chipboard to walk on anyway. I used 8mm marine ply cut to 450mm widths and then did 2 crossways plys to distribute the load.

That is interesting Daffy. I was planning to use sheets of 18mm chipboard and was hoping to space them at 600mm centres at right angles to the direction of the joists which I reckon are about 400mm apart. So that would mean each 2400mm x 600mm sheet will be sitting on 14 legs.

I’ve recently installed another couple boxes worth. I like them. Rated for 50 kg/m^2 but they take my weight (much greater than 50 kg/m^2) no bother and seem solid. Doddle to install. I just used 300 mm wide chipboard loft boards from B&Q so that dictates the spacing but share a loft leg between two boards at the joints so don’t use that many.
I got them from Toolstation (175 mm tall) but I see B&Q do them as well now and I think they are 215 mm tall. I prefer the Toolstation design (they have nice wee dimples to give location and easy start from screws).

You should still have a cross ventilated space of min 50mm above the insulation.

Always run boards perpendicular to joists. Always.

Not had any experience with legs but wanted a heavy duty loft cum elevated garage so fitted lengths of CLS perpendicular to joists and then 18mm T&G chipboard perpendicular to that again. Only issue I had was with one joist that was slightly proud of the rest which snapped, possibly something to do with the shelf of books next to it and the fact it was already cut to fit the hatch (cracks were fairly old as well according to the structural engineer we called out). Redistributed the weight and not had any problems since.

What might be worth doing is getting a structural engineer in to assess your existing joists. Depending on the age of your house they may well be strong enough to support a floor without additional strengthening or if they do need it he will run the calcs for you which then may be a case of running additional strengthening joists along the top of the existing ones. Couple of hundred quid would do it I’d imagine.

Get that crap done early (ask about raising any horizontal beams as well) and you can pre-build your own conversion before moving mountains of crap in and making it a bigger job than it needs to be.

Interested in this as I was looking at these only this week.
As an aside what thickness of insulation is the norm or max these days as I might ‘upgrade’ the loft insulation?

I fitted an extra set of joists 60cm or so above the existing ones, by drilling into the down members of the rafters and bolting through.

A couple of years later I wondered if this was wise… 😳

However the 2ft of insulation is fantastic. House is almost silent in all this wind.

I think the norm depth is something like 290mm.

My loft is 400mm centres so not wanting to use more legs than necessary, I installed them as you would see number 5 denoted on a dice, i.e. every 800mm but with an extra leg in the centre of the joist that is bridged.

If you measure between all the legs diagonally I’m pretty sure they were all on the right side of 600mm centres 🙂

I then ripped 2400*1200mm sheets of 18mm ply (as I’d been given a few sheets) into 2400*600 which was the biggest I could get through the hatch. (watch the length, my roof is quite steep but it was still tight getting them in)

I used the Toolstation ones, two boxes did 3x 2400*1200 sheets I think.

I’ve just finished my loft. Bought the stilts and the chipboard sheets from B + Q, which actually worked out quite good value for money in volume.

It felt like I used millions of the bloody things by the time I finished but they’re over each joist and under each chipboard edge, so every 400mm / 325mm.

I didn’t have any trouble using tongue and groove boards.

Points to consider:

* You’ll lose quite a bit of height and therefore volume. They should offer the stilts in “half height” versions, but I just used the opportunity to add another layer of insulation. You could pull out the rockwool and lay foam insulation instead, which means you can lay the boards directly onto battens screwed to the joists.

* The job is infinitely easier with an impact screwdriver.

* Drill pilot holes in the stilts before screwing them to the joists.

* Decent lighting helps, as does a mask.

* If I’d been aware that Toolstation do shorter stilts, I’d have bought from there.

My diagonal method:

I did this across the main part of the loft and around the edges did 400mm centres to err on the side of caution.

* Drill pilot holes in the stilts before screwing them to the joists.

Yes is a very good idea! My hands were in bits after fitting some recently.

P.S. If you just pick up a boxful of them from B&Q there’s a chance you’ll get all 32 (or thereabouts) for £1.20 total 🙂

Thanks for the replies. Looks like I will give it go. I don’t need to live up there just store all the camping kit and crap from the loft in the old house.

Lof legs from Toolstation for me, and those chipboard loft boards on special from Wickes. Seem very solid and were easy to install.

Depending on your loft I’d keep some 4×2 handy to make up DIY loft legs. My loft has slightly different depth joists in places so I had to cut some 4×2 slightly shorter than one of the loft legs (150mm vs 175mm IIRC)

Scotlandthedave where did you get yours?

sorry, forgot i’d replied on this!

I’m sure i got mine from toolstation, i think Wickes do them too as per tonyd. Check they are the genuine article though, others ive seen are clip on things that look like deathtraps.

Good luck, plan it and take your time and you’ll be fine. good time of year to do it too, my loft was like an oven as i did it in the height of summer….

I did the following:
Fill to depth of existing joists with rockwool insulation.
Fit new joists at right angles, secured with brackets and again fill to depth of joists.
Board over with T&G loft boards and screw down.

Buy a paper suit, mask and goggles – it’s messy. Make sure any cable aren’t buried

slight hijack. I have a room in the roof type house, which british gas has surveyed and said that under the current regs, they won’t help insulate, as there is not enough carbon payback. I have insulated the top flat part, but not the sloping portion or the eves yet.

What is the best way of doing this. How much space to leave between the insulation and the sarking, do you use solid insulation in the vertical bit, or just hang the wooly stuff?

Solid boards like celotex, I think you need a 50mm gap between it and the felt/sarking.
http://www.celotex.co.uk/applications/pitched-roof-insulation

If you want a warm, dry loft space, then the insulation needs to go at the top – either between or under the rafters – with a vapour barrier fitted below it.

others ive seen are clip on things that look like deathtraps.

Do you mean these ones?

As you’re still meant to screw them down

ah. i struggled to see a use for the clips as the genuine loft legs are screwed down, so assumed these were clip only. a little naive in hindsight 🙂

late to the party here, but…

I live in a 1930s semi-detached house. There’s a 6ft strip light in the loft that someone has seen fit to, er, fit, at some point in the past. but it never got boarded.

Without looking (I’m supposed to be working, right?) I assume the ceiling joists are 4×2, is that a safe assumption?
And if so, are they strong enough to take the weight of a 15st fat basket while said fat basket fits loft legs prior to fitting suitable insulation and boarding it ? I know there’s very little insulation up there, I just haven’t got round to sorting that out yet

Without looking (I’m supposed to be working, right?) I assume the ceiling joists are 4×2, is that a safe assumption?

Nope.

Anything from 2×1 to 7×2 depending on who built it.

Our 1930s house has 3x2s up there. I added another set of joists at 90 degrees (as Ransos post above).

ok, so I need to have a look. ok no problem, the hatch is in the “office” ceiling

<edit> 3″ x 2″

safe to board? for storage, nothing like living space? but knowing that I would need to move around up there