CBS Repiping w/ PEX Question

[AaronS.]

I've searched all over the forum and learned A LOT, but still have one issue.

I have a all block house, interior and exterior walls, all exposed block no drywall to help hide the pipes, built on a slab with copper supply lines under the slab.

We have a pretty decent leak and knew this was coming. So we're going to re-pipe the whole house with PEX through the attic using one of the Viega Manablocs. I'm a pretty experienced DIY'er and may do some of it myself. The hardest part will be crawling through the low attic.

My question for you guys is, after I fish the PEX down through cells in the block wall, with hopefully a minimal hole in the block that I can cover up with a escutcheon plate, how do I secure the stub out (which will be copper I'm planning). I've seen the drop eared elbows, and some other pex to copper stub outs that are made to be made to be nailed to studs. I've got a few rigged ideas in my head, but what's the correct way to do this so that there is a solid stub out to attach to?

I'm familiar with the "old work" electrical boxes and they have been a lifesaver in my house. Best I can tell there is nothing like that for plumbing.

 

[CountryBumkin]

There are some installation products on this site that may give you some ideas: http://www.supplyhouse.com/Installation-Parts-521000

I hope you are able to fish the PEX down through the block. In my house (also block construction on a slab) there is a 2x6 header at the top of each exterior block wall and the blocks are filled every so often. Fortunately, in my case the interior walls are 2x4 and drywall.

I suggest you use type "A" PEX such as Uponor ProPEX (AquaPEX) and not the cheaper PEX-b stuff http://www.supplyhouse.com/PEX-Tubing-516000

 

[Sponsor]

 

[Jadnashua]

FWIW, pex-a is more flexible than either -b or -c, but typically uses different fittings. But, by the use of those expansion fittings, you have less restrictions in the pipe since with -b or -c, you shove the fitting in, then crimp it...with the expansion tool and corresponding fittings, you can't insert them until you've expanded the end of the tubing, then it collapses around the fitting, so no crimp rings, and the ID is larger. It's going to be a challenge bending the pipe to come out of the wall, and the increased flexibility and smaller bend radius of the pex-a might help.

 

[AaronS.]

Yeah my exterior walls have some sandy insulation stuff in them, but the interior walls have the 2x6 or 2x8 top plate or header whatever it is.

Yeah. I'm not against putting in an elbow in if needed at floor to stub out.

This is kind of what I was thinking would be most solid, but leaving it on the outside of the wall so I could keep the hole minimal. I just wondered if there was really a correct way to secure it.

But thanks for tips and advice guys.

 

[Jadnashua]

Tapcons might work. Maybe some epoxy. While it's nice to have the stub stable to put a shutoff on, you can put a shutoff directly onto the pex. A typical compression valve will work if you either buy it with the reinforcement (internal) sleeve, or buy a package of them to then use with a valve.