Fixing noise from floor framing

Question

Even after screwing down all panels in the subfloor I still heard noise when walking on a portion of it, so I decided to open it up and see what is going on. I think I found the problem but came across this herringbone strut I believe instead of 2x10 that was used for blocking on all other joists. The herringbone does move and it seems to make some noise as well. The 2x10 blocks are also only secured on the top by 3 staples on each side and might move as well.

I already cut blocks of 2x4 every 16" to get the new piece of floor back in there.

Questions are now:

1. Do I just try to screw the herringbone tighter or replace it with a 2x10 which I don’t have or a 2x4?
2. Do I screw the 2x10 blocks to the struts at the bottom on each side as well?

New to North American construction methods, hence a bit uncertain on how to proceed!

Answer 1

The horizontal blocking does not carry any load of the flooring. It is normally there just to stabilize the joists and keep them plumb before the subfloor sheathing is attached to the joists. The attachment of the subflooring sheeting creates a single assembly of the entire subfloor.

I would make sure the blocking is screwed tightly to the joists before closing up the floor. Then glue and screw the subfloor sheathing down tight to the joists. Gluing and screwing the sub-flooring prevents movement of the sheeting that causes squeaks in older homes that were just nailed in place.

Movement of subflooring sheathing can be eliminated, or at least reduced, in older homes with shims driven between the sheathing and the joists from down below.

Good luck with your project!