Builder removed outer leaf of old external wall - safe?

[edwardo]

the builder came and installed noggins between the joists + made them more secure where they sit on the wall (brick/slate infill between joists). However the floor is still very springy (rattling doors).

The builder is coming back in Feb to install additional joists (going from 9 joists to 13). I'm concerned that this won't fix the springy problem and wondered what the best approach would be.

My thoughts so far:
* evenly space the 4 new joists, but sister them to existing joists with large bolts - creating 4 double sized joists
OR
* use 3 evenly spaced flitch beams instead

then:
* install 2 or 3 rows of cross bracing

* replace the chipboard flooring (pieces are 5ft x 2ft approx) with proper floorboards

* strengthen 3 of the other joists with plywood sistering. Lengths of plywood would be attached to the either side of each joist. Construction glue and strong screws (Decking screws?) would hold them in place. The plywood lengths on one side would be staggered with those secured to the other side, such that the end of one on the left side would align with the middle of one on the right.

Do you think this would solve the live floor issue?

Thanks.

 

[trowlerman]

what about the steel did he extend the bearing ??

 

[tony1851]

So far as I can see, you've not given us the size, spacing and span of the floor joists.
If they're bouncing to that extent, it may just be that they are too small for the span.