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!


With the wall open already, I’d just redo it honestly. Never gonna have a better shot at it, and 70 year old copper thats already crusty isn’t getting any better. I’d go PEX for the supply runs. No torch, no fire risk near old framing, and crimp tool is like $50-80 and you’ll reuse it forever. Sweating copper in tight spots between joists is a pain to learn on the fly.
Keep the last 6-12 inches in copper where it stubs out to fixtures tho, looks cleaner and gives you something solid. SharkBite or proper transition fitting should work. for the clawfoot, supplies through the floor looks way more right than flex out the wall imo. Your already in there so its actually easier now then later. Also swap the shutoff valves while your at it. Old ones seize up right when you need em.
Appreciate all the advice! To address the subfloor comment on the other post lol, I did end up pulling up all the self leveler and the original slab. IDK what the flippers did to that floor, but after I got the self leveler off I was able to pull up the slab with my bare hands in chunks, and it was basically gravel in places. I figured that wasn’t a great base for tile, so me and a friend pulled it all up in a couple hours (which was way less time than I thought it would take).
The joists underneath were in great shape though (hell yeah old growth Douglas fir), except for the one near the tub drain that 1. the flippers cut a 12-inch section out of for some reason and 2. had some water damage from their shoddy tub drain install. I sistered all the joists with 2x10s just to be safe though, and also to help level things out. I put blocking in where the clawfoot tub is gonna go, and am currently in the process of putting down 3/4" plywood for the subfloor. Next will be ditra on the floor, and kerdi board on the walls.
As for the plumbing, I think I’ll take your suggestion (and the suggestions of some of the others that have commented) and replace the stuff that’s looking real crusty while the wall is open. I have pretty good access to all that plumbing from the basement, so I don’t think I’ll have to deal with any awkward angles that risk burning the house down lol. And I’m gonna go ahead and reconfigure the tub supplies to come up through the floor. It does look much nicer, and the shower/faucet kit we got for the tub includes the floor mounted supplies, so it’d be a waste not to use them.