I had a leak in my second floor bathroom, and I'm replacing the subfloor. Is it possible to block between the joists to strengthen the floor? I've not worked with trusses before, what is the best way to reinforce the floor?

My plan after blocking if possible is to use AdvanTech 23/32 with a 1/4" underlayment on top glued and screwed. Will this be strong enough?

size of the joists and the span are important to know..but yes..the subfloor you propose is beefy.

the subfloor is not the question but the structure underneath it

This is the exact setup:

It's an engineered truss system with 2X4's.

This is what it looks like.

http://www.youtube.com/watch?v=Q4lUBaPQvvs

I'm unsure how to reinforce the structure for the subfloor, traditionally I would use blocks between the joists, but with this setup that doesn't seem like an option.

So to further explain, I have to cut out the subfloor in bathroom. 1 of the joists is under a wall so when putting down the new subfloor only a small portion will sit on the joist under the wall since I can only cut so much of the floor.

So, I need to add reinforcement across the 24" for the new subfloor, but because it's an engineered truss I'm unsure how to add reinforcement. Sistering and blocking doesn't seem like it will work.

A lot of new homes have cut cost and gone to 24" centers(it is a nightmare for the tile guys!!!

I will place in my bid, and additional layer of ½" plywood, glued and screwed, to stiffen the subfloor, and it allows me to run the flooring any direction they wish.

that's an interesting system..Ive never seen the truss system before.

Ive seen 24 OC in some townhouses but never got to see what they did underneath. As well 24 OC was common in old farmhouse and colonial builds.

i Don't see why to think you cant block or sister.

what are the bases of the truss attached to once you open up? cant you just frame out fully to sister meaning add a base with vertical support then attach/block to the joist?

or build another truss under your blocking and attach to opposite bases of the joist truss?