Installing copper water pipes underground
Yesterday one of my regular Lee’s Summit plumbing customers referred me to their son in law. He needed a bar sink drain & copper water pipes relocated.
Their location under the basement slab & in the middle of the room was cumbersome. They didn’t need a bar. They needed a play area for their kids. So out comes the jackhammer.
Some considerations before moving these pipes are the elevation of the drain pipe & connecting copper water pipes for underground applications.
A drain pipe relocation is limited by the need for a quarter inch per foot grade of the pipe. Without this it won’t drain properly. And you don’t want the horizontal sections of pvc drain pipe embedded in the concrete if you can help it. If the drain pipe is already close to the under side of the slab there may not be enough room for an extension.
Copper water pipes can’t be soldered underground. The movements of the ground with changing seasons & varying moisture levels could compromise a solder joint. So you’re left with the options of connecting to the existing copper water pipes with pack joint couplings or brazing the pipes.
Pack joint couplings for joining underground copper water pipes are a pretty simple but expensive option. The specialty underground water pipe connectors can run as much as fifty dollars a piece.
Brazing is similar to soldering. But with a copper to copper connection no flux is needed. You use a special brazing rod & heat the pipes to about fifteen hundred degrees. A temperature close to coppers melting point.
Being a master plumber & Lee’s Summit plumbing contractor I’ve brazed before. So I chose the less expensive option. And I feel it’s a stronger joint. Plus it’s kind of fun.
I got to jackhammering quickly. I opened a small trench about eighteen inches wide & three feet long to the exterior wall. Then I hauled away all the large chunks of concrete. I saved the crushed rock & small pieces of concrete for backfill.
Unfortunately, the previous contractor had run 3/8″ soft copper tubing to save money. But fortunately the 1/2″ soft copper tubing I brought had the same inside diameter as the 3/8″ copper tubing outside diameter. So I just slid the new pipe over the old & brazed away.
After brazing the two copper tubes, and burning myself of course, I rolled out the copper tube to the exterior wall. I left about a foot of pipe above the slab grade & soldered caps on the ends.
Now you’re not suppose to put water pipes on an exterior wall in the Midwest. They could freeze. But these will be left in the wall below the frostline for possible future connection. So there was no risk of freezing.
I then connected to the existing ABS drain pipe with a rubber transition coupling & ran pvc pipe to the exterior wall. ABS pipe is known for cracking issues. I left a one foot section above grade & capped it.
After taking pictures of the work for my customer, before covering it, I graded the drain pipe and backfilled with the crushed rock & small pieces of concrete I’d just removed. Then I finished the concrete with a two inch cap of cement. It will be a foot traffic area only. So there’s no need for a thicker layer of cement.
I told my customer to leave it alone for one to two days before covering it. Then I texted him the pictures of the project at each stage. He should see what he’s paying for, after all.
My wife asks me all time why I still do concrete work at my age. But I like it. And I run my plumbing business from my home. So I’m working for my neighbors. And it’s better for them to get a master plumber bid & do the work. The other local Lee’s Summit plumbing companies have journeyman level or apprentice plumbers doing the work under the umbrella of the business owners plumbing license. I want the best for my neighbors.