Sue,

We have cultured marble in our guest bath. We have access from a craft room on the other side of the wall, (If there was ever any need). but most plumbing, ie valves are accessible by removing the cover plate, same as with tile or any other.

DH has a suggestion if you're really concerned about having access to all your pipes. These CM sheets are very thin, you could glue it on with silicone that could be peeled off if necessary, keeping that wall to a minimum, primarily along edges and a bit in the middle. With corian or something that may be thicker and stiffer, you could screw it on, and cover the screw holes with silicone.

To answer your own question, how many times in 23 years did you need access to your plumbing in the shower?

If the building settles enough, even solid surface can crack. If all of your neighbors have similar issues, you should band together and have it inspected by a structural engineer to be sure that there isn't a deeper problem than mere old age and settling mass.

Put in the solid surface and don't worry about access or cracking. That's the great thing about Corian; it can be cut and repaired if necessary and the repairs are inconspicuous.

Install new pipes and valves before the walls. It doesn't cost that much and it will make you feel better.

We can't access from behind; we're in a co-op apartment (so we *own* our home, and remodeling is our right and responsibility), and someone else's shower is on the other side of that wall.

I've been trying to point out to my DH that we haven't needed to access that in all these years; he points out that the guy on the other side is having to replace his shower body. I countered that his is really old, and we'd have all new plumbing (as Trebruchet suggests).

However, we did replace the shower body in the other bathroom, and we did need to go back in to check on whether something was leaking. There, we can get in from behind.

hollysprings, that's true about the settling. I sorta feel that it's gotten worse in recent years. I don't know if anyone else in the building has had problems like ours.

And I'd forgotten about how easy Corian is to repair! We fixed a chip on our countertop once, even.

And I pointed out to him that we could get into the fixture through the coverplate--I'll have to take him in and show him how that works in the other bathroom.

Because the pipes in the wall surely wouldn't need interference.

Thanks, all!

The operating mechanism of a shower valve can be accessed from the front by removing the trim ring. Unless there is a leak on the pipe supplying the shower valve you will not have to get into the wall. If settling is an issue re-pipe with pex which is flexible, and pressure test the piping prior to closing it in.

Consider using either Grohe or Hansgrohe - they have rough in boxes, with built in stop valves. The faucet / diverter / thermostatic control bolts on to the rough in - right from the shower. It's covered by the trim plate.

Here is a link that might be useful: Grohe Rough In Box

Or, like I did, use an external valve. Very popular outside the US... one example from Hansgrohe is linked below - they, and others, also make models with an included shower riser (rainshower or not) and/or handheld. Only the water supplies are in the wall and it's pretty standardized for the distance - and typically allows up to 1/2" play -between the supply pipes so you don't need to stay with the same manufacturer for replacement. The model I've linked has the thermostatic temperature set with the right handle and the left handle is water volume. Very reasonably priced as well.

Here is a link that might be useful: Hansgrohe Ecostat External Shower Valve

Thought I'd add another link showing the Hansgrohe models that are an integrated external valve shower. I chose to mix Hansgrohe and Grohe components instead.

Here is a link that might be useful: Hansgrohe