Inconsistent joist centres for T&G floorboards - do I cut boards or fit noggins???

[Capable Noob]

The floor joist centres are not consistent enough to land the joins of the 2400mm x 600mm T&G boards on joists (anywhere over a 17m span).  So I'm debating whether to cut the boards to ensure all joins are on a joist (thus losing the T&G aspect) or to fit noggins and essentially additional floor joists between them, which will be both more time consuming and costly.  Or can I just fit noggins centrally perpendicular to the joints (presumably this needs the T&G to be in pretty good order, sadly some have been stepped on and chipped a bit so I'd need to be selective)? The boards will all be glued and screwed so I guess square cut edges meeting over joists wouldn't be an issue.   Any advice would be most welcome.

Thanks all

Edited July 16 by Capable Noob

[Mr Punter]

H noggins, so 2 between the joists plus 1 at right angles where the board ends meet.  Can you shift the boards along to the next joist to make it work?

[Moonshine]

IIRC its it tongue and groove on the short ends and these don't need to be on a joist, just glued. However i would put a small noggin in where the joint is (only like a 2 x 2)

[Capable Noob]

3 minutes ago, Mr Punter said:

H noggins, so 2 between the joists plus 1 at right angles where the board ends meet.  Can you shift the boards along to the next joist to make it work?

Thanks for the replies. 

 

Sadly over a length of 17 metres and 40 joists there's no groups that add up to exactly 2400mm so I can't shift along to find a decent place to even start.  Presumably the H noggins don't need to be the full depth of the joist - would 4x2 be ok?

[Mr Punter]

1 minute ago, Capable Noob said:

Thanks for the replies. 

 

Sadly over a length of 17 metres and 40 joists there's no groups that add up to exactly 2400mm so I can't shift along to find a decent place to even start.  Presumably the H noggins don't need to be the full depth of the joist - would 4x2 be ok?

 

If you do the full depth it will help with your plasterboarding.

 

It is annoying when joists are not set out correctly, but it happens often.

 

If the H noggins are a mare just cut the boards back.

[Capable Noob]

2 minutes ago, Mr Punter said:

If the H noggins are a mare just cut the boards back.

So it's not a big "no-no" to just cut the boards and butt them against each other over the joist then? 

The overall floor area is 17m x 5m so a lot of H noggins would be needed and I'm up against it in terms of time as well as energy and enthusiasm lol.

[Mr Punter]

6 minutes ago, Capable Noob said:

So it's not a big "no-no" to just cut the boards and butt them against each other over the joist then? 

 

No issue.  They are best glued to the joists with D4 adhesive plus in the joints.  Messy as hell.

[G and J]

If you’ve got I beam joists or posi joists it might be dangerous to add full height timber noggins to do plasterboard under as well as floorboards over.  Timber will expand and contract with moisture much more than either of them - but if you have full timber joists it’ll probably be fine.  

[nod]

If they are 22 mil boards and glued The ends don’t need to land on a joist or nog Plenty of glue and ring nails 

[Capable Noob]

34 minutes ago, G and J said:

If you’ve got I beam joists or posi joists it might be dangerous to add full height timber noggins to do plasterboard under as well as floorboards over.  Timber will expand and contract with moisture much more than either of them - but if you have full timber joists it’ll probably be fine.  

Thanks everyone.

 

They're 9" timbers (which are the bottom chord of attic trusses).

 

9 minutes ago, nod said:

If they are 22 mil boards and glued The ends don’t need to land on a joist or nog Plenty of glue and ring nails 

It's 22mm Caberfloor.  Funnily enough I thought I'd read that somewhere but wasn't sure.  I think if I did that I'd be forever paranoid about it dipping or hearing squeaks...

[joe90]

2 hours ago, Capable Noob said:

It's 22mm Caberfloor.  Funnily enough I thought I'd read that somewhere but wasn't sure.  I think if I did that I'd be forever paranoid about it dipping or hearing squeaks...

+1 what @nod says above, my floors were caberboard, no noggins and only glued, not a single squeak, dipping cannot occur if the joint is tight especially if glued with d4 glue

[Mr Punter]

So are others suggesting that with, say, joists at 600 centres it would be acceptable to have no noggins at the board ends?  So one end of the board could be unsupported for 500mm, just relying on a glued joint to hold up for an indefinite period?

 

IMO it is not a massive risk but I would rather not take it, especially if the joists are at 600.  400 probably not so bad.

[Dave Jones]

you dont need noggins with the caberboard as long as you 400 centres. 600 may be different. 

[markc]

Good practice to noggin any end joints that do not drop on a joist, any middle ones are supported on both sides so don’t need anything

Edited July 17 by markc

[Super_Paulie]

i had this situation in my place. I worked a full length of the room to find out the best way to start it off so that as many of my short ends landed on a joist as possible. Where i couldnt do it i just had flying ends but once they were glued and screwed and joined to the surrounding boards they are rock solid. Like Mark says above, where they ended against a wall i ran additional joist sections in there any way i could to keep it as close to the edge as possible to reduce any bounce.