Floor joists in attic not supported?

[Dereekoo]

Many thanks.

I assume you are boarding out to store light loads, if not light expect some cracking in bedroom ceiling

 

[Dave962399]

Yep, planning to store Xmas decs etc. previously old furniture has been stored up there which probably account for the cracked ceiling

 

[Dave962399]

Binders have to be supported at the edges otherwise they would not provide any supports to the joists, only add an additional point load due to the actual weight of the binder??

Interesting thought. Assumed they were there to stop the joists from spreading?

 

[blup]

Binders have to be supported at the edges otherwise they would not provide any supports to the joists, only add an additional point load due to the actual weight of the binder??

That’s what I would have thought but they sole/primary purpose seems to be to “stiffen” the joists and prevent twist

 

[cdbe]

I thought binders were partly to prevent twist but mainly to share loads between adjacent joists - I would have thought purely for people walking about up there to do maintenance in the days when people owned nothing to store in their lofts.

 

[Dereekoo]

Interesting thought. Assumed they were there to stop the joists from spreading?

If by spreading you mean buckling then BS 5268-2:2002 Structural Use of Timber following clause gives guidance
2.10.8 Lateral support The depth to breadth ratio of beams of rectangular section should be checked to ensure that there is no risk of buckling under design load. Alternatively, the recommendations of Table 19 should be followed.

Taking the easy route and just following Table 19 depth to breadth ratio should not exceed 3, yours do not appear to do so??

 

[Dereekoo]

I thought binders were partly to prevent twist but mainly to share loads between adjacent joists - I would have thought purely for people walking about up there to do maintenance in the days when people owned nothing to store in their lofts.

Not to share loads as such but to support the ceiling joist so the effective length between supports is reduced and hence smaller sections of ceiling joists can be selected from TRADA tables. As they are usually positioned at 1/3rds or 1/2 along the joist they may assist in preventing buckling ( a bit like floor joists having noggins at 1/3 or 1/2 span) but as ceilings are lightly loaded compared to floors the perceived bounce that is sometimes flagged up when walking on floors tends not to be an issue

 

[noseall]

Binders have to be supported at the edges otherwise they would not provide any supports to the joists,

Not strictly true. There will be some adventitious gain by binding them together - in a similar vein to solid bridging etc.
But yes - they should be supported.

 

[catlad]

Your ceiling is missing its ceiling hangars, normally something like a 2x1 baton and normally from the binder to every other rafter.

 

[Dereekoo]

Not strictly true. There will be some adventitious gain by binding them together - in a similar vein to solid bridging etc.
But yes - they should be supported.

Agreed, should have said "should be supported otherwise they are not doing there foremost task of giving support to the ceiling joists"

 

[Dave962399]

Is any of this a problem taking into account the house is 1940’s semi and, apart from a leaky roof, there seems to be no other problems. Leave well alone?

 

[blup]

I would say yes if the boarding out is for light storage of Christmas decs etc.