Main valve buried in cement needs replacement, How would you break it out?

[tjbaudio]

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?


Thank you.

[big2bird]

Shut off the water, take a hammer drill with a chisel point and just start chipping it open. Make a decent size hole that you can work with, and see what you have.

[hj]

Unsolder the old valve from its copper tube, then solder on a coupling and short piece of copper between it and the ball valve. Although, I would probably solder the ball valve on to the old pipe, it there was enough room for the handle to turn.

[tjbaudio]

Shut off the water, take a hammer drill with a chisel point and just start chipping it open. Make a decent size hole that you can work with, and see what you have.

Thank you. That's about what I had in mind. I have a 12" or 18" long bit for the drill. Start breaking up the 1/2 block above the valve. Once it is out I can work down to the valve and pipe.

[hj]

The solder joint is only about 3/4" inside the wall so all you have to do is "break out" around the valve. You do not have do a major demolition job on the wall, nor will you have to "patch" it afterwards.

[tjbaudio]

One concern I have is that the curb stop is not 100% at least I don't think it is. I was thinking compression fitting to the first valve so I dont have to worry about the little dribble messing up the joint. At the least I could go small on the chipping at first.

[jadnashua]

There are tools and techniques that can handle a slow leak - JetSwet would work and one of those disks that swell, and eventually disolve might work long enough to allow you to solder. You couldn't use a freezing unit, as you'd need access to more of the line in the wall.

[tjbaudio]

Is an old school compression fitting really that bad? I am talking the ones with a metal band crushed in under a wrenced on nut. Not the shark bite crap.

[jadnashua]

If the condition of the pipe is good (nice and round and clean), a compression joint should be okay. It becomes more dicey if the pipe isn't in good shape.

[hj]

I NEVER use compression joints larger than 1/2". The larger ones are too susceptible to failure due to movement. There are lots of ways to handle a small drip through a curb stop, assuming it actually leaks.

[tjbaudio]

curbstop was 100% so I used the smoke wrenceh, pictures to come later.

[tjbaudio]

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.

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.

[tjbaudio]

The problem was 50+ years of turbulent water had worn away the pipe wall just past the valve.

The good news was that the main line was copper and in very good shape.

I was also lucky and found the exact 2 pieces I needed in my parts bin. I did not have to cut the pipe but I did square and debure the ends.


After cleaning up the ends and fitting all the parts, I blew out the lines with air. Next was flux and heat. I put a wet rag around the other end of the valve to keep that joint from heating up too much.

Unfortunatly I messed up the joint at the street side. It leaked after a couple of minuts of pressure. I shut the water back off and was lucky enough to be able to heat the coupling off (wraped the valve in a wet rag.) I think the problem was I had the tourch at an odd angle and did not get all the heat at the correct spot. It could also have been a poor flux job. Second time around I heated the flux a little to make it spread better. I also used a second new coupling I had. So far no leaks! All told it took a little over 1/2 a day. Plan a full day anyway. That bad joint cost me an extra hour. A bad main line would have cost me an extra day or more!

[big2bird]

Nice work. I cannot think of one thing I would have done differently. Kudos.

[hj]

quote; I cannot think of one thing I would have done differently

At least nothing except NOT take a half day to do it.