How to fix noggings

[sparer]

Hi,
I need to build a couple of stud walls that run parallel with the joists. The BCO has told me that I cannot build the wall on top of the floorboards and I must run new double joists. I understand that I can put noggings between the existing joists at either end of where the new stud wall will go and hang the doubled joists from wide joist hangers.

My questions are:
1. How do I fix the noggings to the existing joists. More hangers?
2. Do I need to bolt the double joists together? I have read 400mm centres for the length of the double joist
3. If i do need to bolt together, will M8 or M10 or M12 studs washers and nuts do?
4. The wall sole plate will sit on top of the double joist completely covering it. Where do the floorboards now fix to where they meet the double joist? Maybe another timber screwed either side of the double joist.

Please see indicative diagram attached.

Thanks for the help.

 

[23vc]

1. Yes hangers
2. Don’t think so
4. Yes that’s exactly what I’ve just done, plenty of screws

 

[John D v2.0]

My concern is why are you supposed to have a double joist? Is it purely for deflection or is it for the load? If it's for the load, then I don't see how applying it to the two adjacent joists would help, but if it's for deflection then it would work with hangars as above.
You won't need to bolt them together.
Regarding the floorboards you can just board across the new joists and build the wall on top, no need to only board to the edge of the room. Fixing to the side rather than bearing on top can cause twisting and squeaks

 

[sparer]

My concern is why are you supposed to have a double joist? Is it purely for deflection or is it for the load? If it's for the load, then I don't see how applying it to the two adjacent joists would help, but if it's for deflection then it would work with hangars as above.
You won't need to bolt them together.
Regarding the floorboards you can just board across the new joists and build the wall on top, no need to only board to the edge of the room. Fixing to the side rather than bearing on top can cause twisting and squeaks

Bco mentioned how heavy a stud wall is so I'm guessing he was thinking about load but also deflection if built on top of floorboards with a void underneath. Good idea to board on top of joists. Solves the problem of lots of ~300mm boards.

 

[23vc]

Fixing to the side rather than bearing on top can cause twisting and squeaks

Maybe but I’m a stud walls up before floor down guy, just how I’ve always done it. To be fair it’s only supporting the very edge of the board so I’m not expecting any issues

 

[Doggit]

Unless the BCO has said that you can use the noggin trick, then I suspect he will want you to fit the double joist into hangers fixed into the wall, otherwise you're just transferring the weight of the stud wall and the doubled joist onto the existing joists. Look to cut a slot into the wall using an angle grinder and a diamond blade, and then use slate to make adjustments to the height of the double joists to bring it level if necessary.

Bolt the joists together at 600mm centres with M10 bolts. Drill and set this up before you set them in place, and then bolt them together afterwards, then adjust the height of them if you have to.

 

[^woody^]

You put noggins between the joists every 450mm off hangers and the wall goes on those. No double joists. You can leave the floorboards in.

 

[sparer]

You put noggins between the joists every 450mm off hangers and the wall goes on those. No double joists. You can leave the floorboards in.

I think i'll check that out with the BCO cos it would certainly be easier than double joists.