Q: I have an old house in Berkeley, Calif. It used to have gaslights. The pipes are still visible in the rooms, sticking out 2 1/2 inches from the walls and capped.
I know that there is no gas in these lines, so I would like to remove them and patch the holes. I tried a pipe wrench, but wasn’t able to budge them. I could cut them flush with a Sawzall, but I’d like to get them deeper in order to do a better patch. Any suggestions?
A: Kevin ran into the same thing when he refurbished his 1879 Second Empire Victorian in nearby Alameda. The old pipes were still in the walls — old gas lines, old water lines, and old lead drains and vents.
Kevin did a lot more than you propose. He opened up the walls to the studs, exposing everything. What a 100-year-old rat’s nest! But you don’t have to do that.
We remember when Kevin took ownership in 1982. The walls were in pretty crummy condition after years as a rental, and the color scheme was electric blue and purple, a suitable home for a rock band and just as rough. So rather than try to save some of the walls, he decided to demo them all, to the tune of a 14-yard garbage bin full of lath and plaster.
The result was that Kevin could insulate the exterior walls, add some electrical outlets and lights, and make the walls smooth. A second-order effect is that he got a real good look at the pipes. We’re not surprised that you can’t budge your gas lines with a pipe wrench. You can crank on that sucker till the cows come home and you won’t be able to move them because there probably isn’t a joint to unscrew. In the old days, the fittings that are commonplace today were used as sparingly as possible — we suppose out of fear of leaks and potential explosion.
The weakest link in a gas line is at the joints of the fitting. To install a wall sconce, the plumber would bend the pipe 90 degrees rather than run two straight pieces of pipe connected by an elbow as we would today. We think this is the situation you’re looking at.
In principle, your idea of cutting the pipe off a little below the surface with a reciprocating saw, also known as a Sawzall, is OK, but we see a couple of problems that might develop. Getting at the pipe at a proper depth will be a challenge. You risk destroying the plaster if you try to be too fine with the cut. If you cut the pipe too close to the surface, you risk the patch cracking in the future. …CONTINUED
Our suggestion is to cut out a square of plaster around the protruding pipe, remove the pipe and patch the hole with a piece of drywall.
To start, draw an 8-inch to 12-inch square on the wall with the pipe in the center. With a 1/4-inch masonry bit, drill holes through the plaster at 1-inch intervals. Make sure to drill a hole in each corner of the square. These will lessen the chance that the plaster will crack outside the square when you remove it. Do not drill through the wood lath because it must stay and become a base for the drywall.
With a cold chisel or a stiff putty knife, cut through the plaster connecting the dots. Remove the plaster starting at the pipe, working your way out toward the edge of the square.
Once all the plaster is off, clean the inside of the square so that it’s flat.
Next, cut the pipe. Equip the Sawzall with a long, flexible metal blade. Place the blade so that it’s parallel to the lath. With saw at a slow speed, gently cut the pipe so it’s flush with the lath.
To cover the hole, cut a piece of 3/8-inch wallboard so that there is a 1/4-inch gap on each side of the square. Press the patch on the wall to make sure it fits and the stub of the pipe doesn’t push it out. If the pipe protrudes a little bit, an outline will form when pressed against. Remove a little of the drywall backing so the patch fits flush. Attach the drywall to the lath with drywall screws. You’ll probably find a stud supporting the pipe, so make sure to hit it when you screw in the patch.
To finish, tape the seams with fiberglass mesh tape using mix-it-yourself quick-drying joint compound, sanding between coats. Three or four coats should do it. Follow these steps and you’ll have a patch that will last as long as the wall does.
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