Hey all! This is a bit of a follow-up to a post I made a couple months ago regarding our bathroom reno: https://sh.itjust.works/post/56769265
Long story short, the mortar bed subfloor was crumbling away, and I could literally tear up chunks with my bear hands, so we decided to take it all out. I’m going to sister all the joists to re-level the floor, put in blocking for under the clawfoot tub, then 3/4" plywood subfloor, Ditra, and tile. But that’s not what this post is about.
This post is about all that copper plumbing. I think the stuff above the tub spout is relatively new, but I think everything below that (tub supplies, toilet supply, sink supplies) is a lot older, maybe original, which would make that close to 70 years old. Some of it looks pretty crusty and corroded to my untrained eye, so my question is, should I redo any of that copper while I’ve got the wall open? If so, to what extent, and with copper or PEX? I mentioned earlier that we’re putting in a clawfoot tub, so we won’t need basically anything above the tub spout. I know clawfoots traditionally have supplies coming up through the floor, so I may end up reconfiguring to accommodate that, but I’m also considering taking the easy way out there and using some flex hose coming out of the wall.
I don’t have a torch or a PEX crimping tool, so either way I go I’m gonna have to buy a new toy. But which one? How would y’all go about this? Thanks in advance for the input!
I’ve had 50 year old copper develop pinhole leaks from internal corrosion but it depends on your water quality. I would replace everything that’s easy to access while you have it all open. That should be a relatively moderate additional overall expense and could save you huge regret later.
But if you sweat the copper yourself and do a mediocre job you could regret it much sooner. It’s not excessively difficult but there is a bit of an art to it. Watch some videos and practice on scraps first.
Clean the copper ends very well. Especially on the ends of the existing pipe. Buy tools to make that easy. Use flux (apply with an acid brush). Wash off the flux residue after the joint cools. It’s corrosive, but you really only need to wipe it away with a wet rag. A simple propane torch is fine, but you need to hit the correct temperature. Watch the rainbow color changes in the copper while you practice. Also buy a a flame cloth/heat shield to protect your structure (not strictly necessary, but you’re a beginner).
Copper is expensive these days, but don’t cheap out with M-type. Use L, which is slightly thicker. K is only needed when buried outside.
PEX B is pretty easy (except for tight spaces), but you need to ensure you get correct alignment of the crimp rings, and use the checker tool to ensure correct crimping. The plastic degrades in UV light and is a flood risk when accessible by chewing rodents in breached attic or crawl space. Use copper stub outs if you go with PEX. You can crimp onto those, but you’ll still need to sweat on a copper/PEX adapter at the point you cut the existing pipes.
PEX A requires much more expensive tools and it’s only appropriate for professional plumbers. Same with ProPress (crimped copper), which I think is inferior to sweat fittings anyway. It’s optimized for installation speed & reducing labor costs, and the seal comes from embedded EDPM gaskets rather than solder.