Delta shower valve trim and strange install

[Redbird611]

While trying to update the handle/trim on a Delta shower valve I ran into a problem. After removing the escutcheon I discovered that the valve bracket was not installed on a stringer, but rather loosely attached behind the valve. One of the tabs with the escutcheon screw hole was bent slightly and I couldn't get both to thread at the same time.

Unfortunately, after manipulating the bracket too many times it detached (or maybe was never attached) and fell down between the walls. Now I'm trying to decide how to address this. The valve seems reasonably secure despite the lack of stringer. From what I can see the upper copper pipe is strapped to metal blocking a few inches above the valve (high rise condo). I'd like to find a way to attach the trim properly with minimum expense or wall damage.

The only idea I have so far is to open an access hole in the opposite wall (closet thankfully) to place a replacement bracket on the backside of the valve, then wire tie the bracket to the valve so it doesn't disappear down the wall like the last one. That seems a little jury rigged, so I'm wondering if anyone has seen this kind of valve installation before and might have better ideas.

 

[Dj2]

Open the wall on the other side. Can you move the rough in, or is it stable?
Sometimes, plumbers secure the hot/cold pipes to studs or blocking, bad practice but you never know.
If not, install a horizontal blocking and attach the rough in to it.

 

[Sponsor]

 

[Redbird611]

Open the wall on the other side. Can you move the rough in, or is it stable?
Sometimes, plumbers secure the hot/cold pipes to studs or blocking, bad practice but you never know.
If not, install a horizontal blocking and attach the rough in to it.

No, the rough in doesn't move. I've never had a problem with the handle/assembly moving during use. Given that it seems stable as is I'm comfortable not messing with adding blocking until a larger bathroom renovation and/or valve replacement. If I don't have blocking to attach the bracket to I'm wondering what the best method is to stabilize the bracket to the valve body. Would nylon cable ties be appropriate? The ones I have seem to be rated up to 185 degrees, which sounds sufficient.

 

[Dj2]

Based on the latest info, I would replace the rough in body. Brand name, rough in and trim under $100.
You could run a horizontal block behind the rough in and then use long screws for the cover plate - I wouldn't do that, you might pierce the pipes by accident.
Metal wires, plastic ties for the cover plate - they don't belong here.