Hi Is it practical (i.e. is there enough working space) to fit herringbone strutting between joists when you only have access to the joists from below, the top side being floorboarded?
Plan B is to brace using timber and skew nailing, but the joist centres and joists sizes are not consistent making cutting the timber to size a bit of a chore.
thanks tony
What are you *actually* trying to achieve? If you need noggins to stop the joists twisting, these should be fitted perpendicular to the joists, and should be almost as tall as the joists themselves. If you offset them, you can nail through the joist into the end of the noggin.
Its actually better to use herringbone - its recommended building practice, and yes, its possible though awkward to install from below only.
I sort of assumed it was done to allow easy access for pipes etc. And maybe even timber costs. The Victorians seemed paranoid about this. But can it be stronger than just a lump of the same size as the joists nailed between them? This is what they used on my new work - under the eagle eye of both a BS and architect.
Of course noggins work IF they are cut exactly to size.
But herringbones get nailed in and because on the slant, end up jammed in between.
Easier to fit and make a decent job for hairy arsed chippies :-)
Not exactly difficult?
Well, that might stop a twist in one direction...
They are fitted in pairs making an X shape between the joists.
My Victorian house has loads of them under the first floor, but oddly none on the ground floor joists.
Phil The uk.d-i-y FAQ is at
Mine has on the ground floor too - easily seen from the cellar.
Usually the ground floor joists are 4x2 off sleeper walls so you don't need them. BS5268 only requires strutting (at max 6 x the joist depth) where the joist depth/width is more than 5. If it is 5 or less the only requirement is for the compression edge to be held in line, which it will be when the flooring is nailed to it.
That's how mine are done.
Does that mean if you have 7x2 joists the struts/herringbones are only needed on pairs of joists 42" apart. i.e. the intermediate joists do not need strutts? I hope so as only some of my first floor ones are strutted.
So all 7x1 joists need it, but no 7x2's require strutting at all? My upstairs ones are mainly 7x2, though I think I remember some skinny ones too. Maybe they are the ones strutted.
Phil The uk.d-i-y FAQ is at
No the spacing is along the length of the joist, but ...
by the code the depth/breadth ratio is 3.5 so the only requirement is for the ends of the joist to be held in position and the members held in line "by tie rods or binders". For floors the strutting requirement effectively only comes in for D/B>5 - so if you had
8x1.5" joists they would need rows of strutting every 48"
Thanks for clearing that up.
Phil The uk.d-i-y FAQ is at
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