Stubs for pex fixtures

I have type L copper in my home and get pinhole leaks that require me to rip out drywall and replace copper once a year or so, needless to say it's a PITA.

So I am replacing with pex. I have the manifold installed and connected up on 1" copper through a whole house filter - now when I run my pex to my fixtures I was intending to sweat a HydroPEX Brass Sweat Adapters onto the existing copper stub under the sink(s) (or replace those stubs with new type M copper and new shut off valves while I am at it)

My questions are :


1. Is this an acceptable approach ?

2. How do I secure the stub to prevent movement

The alternative I have is to take copper via a copper 90 and secure beneath the sub floor to the joist.

Thanks

If you are doing a full re-pipe on your home, don't cheap out on the last bit and reuse your old subouts and valves.

Since you are intending to come up through the floor with your new runs, using a proper pex stubout elbow w/ mounting flange probably isn't going to be long enough for you. And so I suggest since you are having problems anyway, that you look for an alternative to copper to stubout with and thereby eliminate copper all together from the household plumbing, or you stubout as you intend using thicker type K copper instead of type M.

I use type L copper for my installations because the price difference is negligible, but type M is usually what they sell in the big box stores, and it is the thinnest wall coper tubing of the 3 types.

copper stubs

Use type L in 5 inch lengths, sweat in a 90 and add a pex adapter on one end and a cap on the other if you're not using it right away. Drill a hole into a 2x4 blocking and slip the copper through it. Secure it with a clamp from the back side. Intall the pex lne and insert the block with everything attached into place. Drywall and put your compression stops on. Done.

Or just buy the commercial stubout fittings but I prefer the clamp to the flange they use.

?

IF the water is deteriorating type "L" copper which is fairly heavy, WHY would you even think about using type "M" for anything. Given the circumstances, even type "L" might be risky. Unless the leaks are in a hot water system with a recirculator, and the leaks are being caused by velocity erosion.

While harder to support, you can buy shutoffs made for pex...just run the pex where you want it, then install the shutoff.

Since you're having pinhole problems with your copper, I definitely would not re-use the copper stub-outs. Run the pex through the sub-floor, and all the way to the fixtures. If you need a stop valve, install an in-line pex crimp stop between the floor and the fixture.

Brasscraft compression stops can be used on pex...you just need the ss ferrule insert so the compression fitting doesn't collapse the tubing.