Hi! We are plumbing a new bathroom with 1/2" copper. A friend advised me to avoid joints in the copper under the sub-floor where they could not be accessed if they leak. (The sub floor will have tile over it when finished). My plumber says this should not be a concern and we can have a 'T' junction under the sub-floor without worry. What do you all think: avoid it or don't worry?

So long as you do a good job, I wouldn't worry about it.

There's no such thing as non-removeable... there's just 'how much does it cost to remove it'


If you're concerned, you could plumb it with PEX and a manifold... that way, all connections will be outside of the tiled space, and if there's a problem you can attach new pex to the old pex and pull the new stuff through, like fishing an electrical cable. Make sure the supports are loose enough for this though, if that's your plan.

But really, a well-soldered and properly sized joint won't leak any more than the copper pipe will. If you're worried about corrosion, I guess you could probably paint the outside of the pipes/joints too. If you use something like POR-15, it oughtta be strong enough for anything.

Good luck!