Furrings back to back on joists

[Moonshine]

We are laying the furrings out on joists and they are going back to back to create a mini ridge.

Where the ridge is formed back to back they can be on a joist but the joist is only 47mm wide, so each furring will get ~23mm to rest on. This seems too narrow and wondering if its best to put a noggin in under the joint to provide more bearing. The furrings havent been cut to length yet so can make this change

 

Or

 

Edited July 13, 2022 by Moonshine

[nod]

Yes 

I would fire a length timber along the full length of the ridge either side 

[Moonshine]

11 minutes ago, nod said:

Yes 

I would fire a length timber along the full length of the ridge either side 

Like this?

 

[joe90]

I would prefer noggins all the way, what depth are the furrings at the other end? Are they deep enough to carry the weight of the roof (snow loading!!!) I have always put furrings on top of and along the joists, not across them 🤔

[Russell griffiths]

Have you got any more joists, if so put a double joist there. 

If not do as nod said. 

You should have some form of noggin in those i joist anyway. 

Should be a couple along the length to stop buckling. 

Edited July 14, 2022 by Russell griffiths

[Moonshine]

49 minutes ago, joe90 said:

I would prefer noggins all the way, what depth are the furrings at the other end? Are they deep enough to carry the weight of the roof (snow loading!!!) I have always put furrings on top of and along the joists, not across them 🤔

 

I have gone with noggins as its only 6 furrings back to back on this section of roof. They are deep enough at the thinnest point for that very reason. On the other larger section of roof the back to back furrings are sitting on a 100mm joist.