Insulation Under Lay Board

[thomp1983]

Hi all,

As you an see above our builder decided to install the last few roof trusses where it meets the original roof without lay boards.

I've managed to cut the trusses insitu so I can slide a layboard under the and resecure, should I pack the orange sections that will be under the layboard with rockwool, the other side of the board is a bedroom.

My concern is trapping moisture between the plasterboard and layboard, would I just be better leaving the gap under the layboard empty then lay rockwool over the top of the layboard as you would in a typical loft?

Thanks
Chris

 

[DAZB]

You would rockwool between the joists. What size are those timbers as they look a bit thin to me ?

 

[thomp1983]

Timbers supporting the original roof are about 4x1 the new timbers are 8x2.

The original timbers are about 40 years old and never been an issue, there now supporting very little due to the extension, I just want to join them all together with a layboard as currently the new roof trusses are causing point loads on them which isn't how it should have been done.