Main valve buried in cement needs replacement, How would you break it out?
Hello, I have an old house that has had many changes over the years. I am not sure when the pluming was changed from a well to city water main, could be the 70's could be the 40's. The original foundation is stone. At some point the basement was dug out (or possibly added) and the stone backed up with cement block and the space between the block and stone, a ft or 2, back filled with pea gravel. The original water valve was partly buried in the cement block. I have no idea what kind of pipe is in the wall, if there is open space or what not. The existing valve was sweated to 3/4" soft copper tubing on the inside. A few years ago I added a ball valve. The joint out of the original valve is now leaking and I need to dig it out and do a proper fix. Monday morning I will have the city shut off at the curb before I start to hammer at it. Given what we know, or don't know, how would you bust out the old valve? I want to minimize damage to the pipe and nearby sewer line. I have several tools at my disposal. A big hammer, 1/2" flat stone chissle, 1" star chissle, hammer drill, pneumatic chissle, large and small side grinders with masonary blades.
With any luck I should end up with a copper pipe I can just use a compression fitting on. Do I need to cut it off or can I use a compression fitting over the tinned end? I expect I will have to back fill the hole with cement as well. Any speculation on what else I may find for materials hidden away?
Repair done, with pics and how to.
Water guy came out at 9am today to turn off the water. In our town they leave the tool for me to use till I am done with the repair. Also, no charge to turn off the water for a repair.
First I drilled a ring of holes 2 to 3" deep. This forms a frature line and a starting point to chisel from.Attachment 18088
Next I started with a hammer and star chisel I very soon changed over to the air tool!
Start at the holes and work in.
As you get close to the pipe be vary carefull. Remember, cement has almost no tensile strenth. I scored the cement but did not get close to the pipe with the air tool.
Once I got to this point I used a 1/2" chisel and very light taps. Think dentist chipping at a tooth. Very light and easy. This part only took a few hits.
Finaly, ready to work on the pipe.