do i need noggins in floor joist?

[rssteve]

my builder has laid my floor joists and is building up to the roof plate. Hes now away for a week abroad, i want to start pulling some cables in but the floor does not have any noggins in yet!. the soan is 4m one end is joists hangered onto the wall. the other is laid into the block work. Will it just need one run in the middle or more than one set of noggins?

thanks

 

[noseall]

if they are conventional timber joists then they will require solid bracing at mid span.

they should also have a bent galv restraint strap built into the brickwork and laid across 3 joists.

 

[rssteve]

if they are conventional timber joists then they will require solid bracing at mid span.

they should also have a bent galv restraint strap built into the brickwork and laid across 3 joists.

ok thanks.

the floors not down yet they have only just laid the joists. Will the restraint go just in the middle where the noggins are?

 

[noseall]

Will the restraint go just in the middle where the noggins are?

yes. don't forget to chisel 'em in, so the floorboards sit tight.

i purposely saw a bit off the first couple of noggins to allow for the thickness of steel.

 

[Bowness72]

As well as the central noggins, there should also be a line of noggins at the joist hangers.

 

[noseall]

As well as the central noggins, there should also be a line of noggins at the joist hangers.

this is something i've not personally come across but authorities vary and i can see the logic, particularly in some brands of build-in joist hangers.

not all authorities insist upon mid-span straps for instance.

 

[Bowness72]

I have only just found out that a noggin should be installed next to joist hangers. I haven't seen it in the building regs, only in the NHBC regs although may be a bit of overkill as the joists tend to be restrained by the floor boarding and ceiling anyway.

 

[^woody^]

Although for a 4m span only one centre noggin is recommended, you really want 2 noggins at 1/3 span centres as this does a much better job for joists of 200mm depth and greater - or of 600mm joist spacings.

The noggins will greatly add to the stiffness of the floor, so there is a structural element to using them, but also it is more of a practical benefit of removing the bounce from the floor.

Also you should really put the noggins at the same time as the joists, to prevent them twisting as they dry out.