I’ve been laying flooring up there so I can store more junk. It’s just empty boxes, small bits of furniture, and random crap but it occurred to me that all the flooring and associated woodwork and the 50cm of insulation all add up to a lot of weight.

Are there rules or guidelines about this? Will the roof collapse and crush us all whilst we sleep?

molgrips – never stop posting on here! Ever!

Go and tell your story on my love thread though please.

what dimensions/spans are the ceiling joists?

I didn’t read the love thread, I thought it would be a bit much 🙂

The joists are smaller than normal joists – probly 40mm wide and what, 90mm high? Dunno. 600mm apart tho.

how do you get 50cm of insulation between the joists if you’ve boarded over them?

Oh c’mon Molgrips, you and MrsGrips are our David and Victoria…

so possibly Ex 2″ by 4″ @ 600mm c-c, but what unsupported span? (i.e. from wall to wall)

Slight hijack

What is the recommended type of boarding used for lofts? ours is half boarded and I’d like to complete it. the stuff that is there has nice junctions so that it slots together easily – sort of like tongue and groove. is there a minimum thickness that you can stand on? Also where can you get it?

Cheers

how do you get 50cm of insulation between the joists if you’ve boarded over them?

I put the insulation down, then installed extra joists bolted to the rafters.

Unsupported span – hard to say. The actual loft is maybe 5m from side to side, but the house walls are further away than that since the upstairs rooms have that bit of sloping ceiling in the corner.. know what I mean? Also I don’t know if any of the walls inside the house help to support the joists.

installed extra joists bolted to the rafters.

and that’s what the floor is resting on?

I’d be really careful – the rafters are really heavily laden with the weight of the roof tiles/slates they’re not really designed to have weight hanging from them at a point where there’s no ‘vertical’ support.

well as a guide then, the TRADA span tables say ceiling joists have maximum spans for 38mm x 97mm at 600mm c-c of 1.67m for 0.25kN/m2 dead load.

101.972 x 0.25kN = 25Kg/m2

if you go out to, say 3.0 or 3.5m with those dimension joists, well you can have a feel for what its going to do with the permissible specified dead load. (of course we’re doing all this the wrong way around – you’re supposed to start with spans and then work back to specs)

Im also not sure how the binders might effect the calculation. Im not a structural engineer.

what is this new ‘false floor’ attached to the rafters with?

what is this new ‘false floor’ attached to the rafters with?

christmas spirit.

Are there rules or guidelines about this?

I think the general rule is that lofts are not storage areas. The loft hatch is there for access in case of any maintenance requirements. Any catwalk which might have been placed at the time of construction, is there purely to facilitate access, not for storage purposes.

its illegal to use your loft to store/grow/prepare drugs

HTH x

I think the general rule is that lofts are not storage areas.

😯

Who doesn’t fill their loft with junk?

Great, now I’m all worried, thanks 🙂

Anyone wanna buy some timber? And some junk?

Seriously though, I should be looking out for cracks in the paint on the ceiling underneath, and seams between plasterboard boards becoming visible, right?

I think the general rule is that lofts are not storage areas

I’ll move that big tank of water when I get home then. 😉

its illegal to use your loft to store/grow/prepare drugs

HTH x

That’s what basements are for.

the joists under a water tank and it’s location usually near a load bearing wall are usually specified to take the additional load. That wont necessarily extend to the full use of the loft space.

I should be looking out for cracks in the paint on the ceiling underneath

no, you’ve created a new floor which doesn’t have the ceilings attached to it so the joists won’t be flexing as weight is applied to this new floor – they’ll be under tension fromt he rafters trying to ‘pull’ them apart.

What you need to look for is the rafters deflecting/bending under the weight of your new joists/floor/junk – this is going to be more difficult to spot but, potentially worse as any movement will have an immediate effect on how the roofing material sits.

Lie in bed. If you can see stars….

If you can see stars….

someone’s stolen your roof…

seeing the amount of snow in some parts last week had me wondering about how long it will be until we have the first roof caving in from the extra weight.

in the alps all roofs have to be able to take the weight of a meter depth of snow. maybe we don’t need these extremes but snow adds a lot of weight.

…but not in mineapolis:
[video]http://www.youtube.com/watch?v=o2K53bkzX2I[/video]

Who doesn’t fill their loft with junk?

Most people do. You asked, “are there rules or guidelines about this?” and I gave you an answer.

no, you’ve created a new floor which doesn’t have the ceilings attached to it so the joists won’t be flexing as weight is applied to this new floor – they’ll be under tension fromt he rafters trying to ‘pull’ them apart.

Ah.. my new floor is not attached to the actual rafters that the tiles sit on.. just the downward members that support the roof and rest on the joists.

Beginning to wonder if this was a good idea.

TBH I think the only even remotely structurally acceptable way of adding a floor void in the loft space is to run joists across the top of the ceiling joists in perpendicular orientation, spreading any load evenly across the ceiling structure. Even then, you’re making assumptions as to the ceiling joists ability to not deflect under dead/imposed loads.

The boards are spreading the load just as well as perpendicular joists would.

And it’s not like there’s TONS of stuff up there. The boards and extra timber weigh more than the stuff which is worrying.

so are the floor joists resting equally across all the ceiling joists?

One extra raised floor joist per ceiling joist.

Just had a thought.. I should put stuff towards the edges wherever possible.. heaviest stuff first.

Actually this could improve matters, since I am adding flooring towards the edges isntead of just the middle.