Want to convert some loft space (1.8mx3.6m) for storage.
Current (done last year) insulation is about 13cm above the height of the joists.
Looking at running some timber perpindicular to the current “horizontal” joists, at about 60cm spacing and then putting 18mm chipboard on top.
Do I need to put anything horizontally between the long timbers?

Just trying to get the materials priced up (doing the work for my mothers house)

Seems like a straightforward job to me but feel free to tell me otherwise!

i did this a couple of years ago. Loft boards need 30-40cm centers, I think 60cm would be too far for 18mm ply (but happy to be proved wrong). If using loftboards (which I’d reccomend, as they make the job dead easy) you also need to make sure the joins between them are over the joists. I ran 2x4s on end, and secured them to the existing joists using 6″ screws straight through, and a beefy drill driver (went through 3 battery charges doing it). pilot holes are a good idea in ply cos otherwise its a b*gger to get the screws in.

Insulation is 55cm wide I think hence 60cm spacing

yeah, cutting that stuff up – in fact, even moving it at all is a right pain, the fibers get everywhere, be ready to have very regular showers 🙂

Thinking back, mine is spaced at 60cm centers because I have 4×2 loft boards, and 2 supports per board. floor doesn’t seem to flexy. The loft boards have t&g throughout which helps.

If there’s any chance you’ll want to change the lights in the rooms below, do it first 🙂 I took the opportunity to add lights in the loft, which didn’t take long either

H

I’ve done it at 600 centres and it’s fine. it’s not like you are walking on it everyday, if it’s just for storage.

Could do 40mm spacing (just checked, and the insulation seems to have pre-cut sections (although not currently seperate so can be reduced to 40cm wide).

I’ll need 2×6 to get the height I reckon.

What about anything in between the long timbers?

The loft boards have t&g throughout which helps.

If they’re 18mm or more thick, and you’re running 2×4 batons perpendicular to existing rafters. Bear in mind, they’re rafters, not joists (i.e. not supposed to be particularly load bearing…so check the depth of them!), then as long as your new batons have ~400mm centres, you don’t need to have the joins in line with the batons. The t/g join is strong enough to hang between batons.

You should also drill clearance holes for the screws. Seems like a faff, but shortens the job.

Best of luck.

Oh, and what options do I have for fixing the 2×6 to the current rafters?

Normal wood screws? Joist screws? Countersink them?

i used something like this

http://www.screwfix.com/prods/45097/Screws/Interior-Wood-Screws/Spax/Spax-Countersunk/Spax-Single-Thread-Woodscrews-6-x-180mm-Pack-of-100

and a big driver

Oh, and what options do I have for fixing the 2×6 to the current rafters?

I’m not sure you’d really need 6″ batons – 4″ would do. If you’re trying to fix 6″, you’ll need mahoosive screws! Also you could secure them with L-brackets – onto the sides of the new batons with one side of the L and then into the existing with the other side, if you get my drift.

As for screws, Spax are good as are Fischer as are Screwfix’s own brand Turbogold. You’ll want 2″ screws for the chipboard loft boarding and for fixing the batons, that will depend on your fixing method.

Going on 2×6 due to not wanting to squash the insulation.

18cm screws are looking a. expensive and b. silly

18cm screws are looking a. expensive and b. silly

Which is why I’m saying that you just fix the batons to the existing rafters with just L-brackets. That way you don’t have to use silly size screws. You’d need a meaty driver to drive 18cm screws 😯