Hi,
My roof trusses are made from 3" x 2" and there is a 4.5m span between the wallplates, with just one internal tie from the apex to the mid point of the joist. It all looks so flimsy that I'm quite nervous about storing anything up there.
I had originall toyed with the idea of putting proper floor joists in so that I can use it for storage, and then should I wish to do a full loft conversion at a later date, the floor would already be up to the job. For various reasons, I am moving away from that idea, but would still like to beef up the floor by putting joists in raised a little further off the wallplate for clearance.
Anyway, I;ve done all the calcs, and to satisfy the regs, over a span of
4.5m I'll need to use 2.5" x 9" on a 600mm pitch, or 2" x 8" on a 450mm pitch for this floor to be upto loft conversion standard. Thats a lot of expensive wood, and as I'll now only be using it for storage (admittedly there will be books, and some heavyish stuff), how would I quantify the risks of putting in 2" x 6" on a 450mm pitch, for instance. It is clearly not up to everyday domestic use, but i am guessing that it will be sturdier and a better solution thatn just laying boards on the 3" x 2" trusses. What I can't grasp is the effect of the tie in the truss that runs verttically from the apex to the centre of the horzontal. Does this effectively halve the span of joist? If so, is 3" x 2" over 2.25m any better/worse than 2" x 6" over 4.5m.In anycase, not laying boards on the trusses appeals as I am less likely to crack the ceiling below while walking around, moving boxes etc.
Any thoughts?
Cheers
Chris