moving plywood seams

[scott anthony]

I have inspected a house yesterday and find the floor and support structure just fine. There is a lay of 3/4 ply on top of 2 x 8's. I noticed the ply is not T and G because a few of the seams can move when direct pressure is applied. The movement is about a 1/8. I know I need a backer but I want to keep it at a 1/4 do to the fact the cabinets are in already. Not my way of doing it there.
Short of cutting out and under scabbing the loose edges, does anyone have a more efficient method?

[bbcamp]

Add blocking under the seams.

[Sonnie Layne]

Ditto,

attack it from under. If this isn't possible, get back. You'll get more ideas than you axed for

[Davy]

I like Bob's idea too.

[scott anthony]

That would be too easy. The underside is all ceiling.
Do they make an epoxy that you can fill the seams with?
I know wood glue is stronger than wood itself. I just don't want to use something that might work. I have no problem cutting out a 4 x 8 an under screwing a 8 x 14.


I was just hoping for an easy way out.

[stullis]

2x8 floor joist not good single layer plywood that isn't T&G definitely not good... and you were saying that the floor and support structure is good?

[scott anthony]

The structure supporting the ply is good. I do know the ply itself is the weak link. The ply is in very good shape other two slight movers. Removal is out of the Question and the hight comes into play.
Would you walk from this one?

[stullis]

You either have to block the plywood seam joists from below as was suggested or put another layer of plywood down.

I would walk if the customer did not want to pay for bringing the floor up to needed specs.

You say there are only a couple of spots bad? Is it possible that they did use T&G but the tongue was bad on those couple of spots? Maybe you would only have to lift a sheet or two of plywood to repair. How big of an area is this and what is the span on the 2x8 joists?

[scott anthony]

The 2 x 8 s are at 16" and are supported directly through the middle of this simple 180 Ftr.
I can block it from underside but I am not going to rip apart their house to do so.
The way I would do this is as I explained prev--- screw a grab handle onto a 8 x 14 ply and glue and screw. I know it won't move any more. Or better yet cut out a 3x141/2 and attach a 2x6 onto the beams verticaly and also to the ply. I 'm not sure if your follwing me here.
There has to be a better way.


Thought: Rip at the seam of the 3/4 ply 7/8ths of the way through and use a wood bond of some sort that is stronger than the wood itself. This would leave a 1/8th cut line to fill.
And then the application of the backer would add extra support.
Them areas can be marked for extra screws.

[bbcamp]

You won't be able to edge glue plywood.

Pull up one sheet and add blocking from the top.