Cutting concrete floor

[mark1]

Ok people I need your help! My old house (built in 1960 or so) has the old cast iron/lead plumbing pipes.From my cellar about 3 feet up they go thru a block wall and under a concrete floor under a kitchen.then to a bigger pipe and out to the septic. Years of power snaking has fineally created a leak. Now I need to cut out about 12 feet of concrete floor to replace the pipe. What's out there to cut the floor. Fortunatly most of the floor is axcessable. but it's all inside the house! And what are they using now for pipe.I believe it is 2"" I think the concrete floor is 4-5" thick
Help
Thanks

 

[Egon]

You could rent a concrete saw for the cuts. It will dusty so you should wear a proper mask.

You can also drill a few holes in the concrete to determine its thickness. Use a masonry drill bit.

I believe Scotty is quite familiar with the procedures involved and he may sign in.

If not able to rent a proper saw an angle grinder with a concrete blade should be able to make partial depth cuts. After that numerous drill holes should allow you to remove the concrete.

It would be nice to have a nice straight smooth saw cut for finishing purposes when you replace the concrete.

 

[AlanB]

Concrete saw and either deal with the dust (plastic sheeting and duct tape are your freind), or saturate it with water, and deal with the mud and the runoff.

Nothing clean about this task.

Just kind of got to dig in and get going, it sucks know matter how you go about it.

 

[ray66v]

Don't cut it dry. It does not take a lot of water to minimize the dust.

 

[mopacman]

When we had to replace the sewer to to my dads house he cut a hole in the wall and made a bit big enough to run a 4in plastic pipe through. We went 15ft under a concrete porch and past a big tree next the house and came out in a hole we had dug out side. The bit was made like a post hole diger. We had a small 10-1 right angle gear box run by 1/2in drill motor. We could dig about a foot then pull it out and clean the dirt out. It took about a day to build the rig and a day to drill the hole.........Larry

 

[EddieWalker]

Why do you need to cut 12 feet?

I would cut around the pipe that comes through the floor first. I seem to do this a few times a year to either relocate a line or add one. I use a diamond blade in my 7 1/4 inch cicular saw and cut it as deep as it will go. I've never tried adding water to the mess, I just deal with the dust. I used to drill the corners with my hammer drill and chip out the concrete with my air hammer. This worked, but it was time consumeing and allot of work. Now I have a Hitachi SDS Max Rotary Hammer. It is the latest, greatest thing for drilling concrete. I just put in the bit and press the trigger. It just about melts through concrete. It also has the ability to be a small jackhammer that is just amazing at how well it works. If you don't have one, don't ever think you will need one, then rent one for the job.

After the concrete is out of the way, cut the pipe at the elbow and remove it. You will have to dig a pit out side the house to pull the old pipe out and slide the new pipe in, but that's pretty basic. Just be sure to cover the end of the pipe with a cap and tape it into place!!!

I always use Schedule 40 for my drain lines. You said this is a two inch line, so that means it's for a shower or sink drain. Toilets should be on a 3 inch line. Never cut a corner and go with drain pipe, it's thinner, but also weaker.

Only use purple primer and heavy duty clear glue. The others have all proven to fail, and are mostly designed for special applications that don't apply to what you are doing.

Eddie

 

[FrogLick]

When we had to replace the sewer to to my dads house he cut a hole in the wall and made a bit big enough to run a 4in plastic pipe through. We went 15ft under a concrete porch and past a big tree next the house and came out in a hole we had dug out side. The bit was made like a post hole diger. We had a small 10-1 right angle gear box run by 1/2in drill motor. We could dig about a foot then pull it out and clean the dirt out. It took about a day to build the rig and a day to drill the hole.........Larry

I'd be interested in more details about the rig you came up with. Any pictures? I need to run some lines under a driveway (water & electric) for a new barn and hiring a horizontal boring contractor will probably be $$$.

 

[mopacman]

This was done about 45 years ago. The tool looked like a post hole diger that you twist with a T handle. We used pipe to drive the diger just like the post hole diger. The angle drive was a 1928 chevy steering box which would rotate 360 deg. This was built very crude and simple was made of pipe and flat steel that was laying around. most was welded together. For smaller pipe dad would take 1/2 in or 3/4 inch pipe and cap the end of it, then drill something like 1/8 in holes in the end of it. He would hook a garden hose in it and push it through the dirt. I have used this to poke a hole about 10 ft deep with out any problem.....Larry

 

[MarkV]

I'd be interested in more details about the rig you came up with. Any pictures? I need to run some lines under a driveway (water & electric) for a new barn and hiring a horizontal boring contractor will probably be $$$.

FrogLick if your soil isn't too rocky you can use a water jet to get under the drive. Basically you glue a jet end onto a stick of PVC, the heads are sold at Home Depot, and a garden hose fitting on the other end of the PVC. Dig a ditch on either side of the drive, turn on the water and push your probe in to cut pull out to wash away the spoils. It is a bit of a mess but it will get you there. One piece of advice, make sure your ditch can drain the water away or you will be up to your knees in muck.

MarkV

 

[EddieWalker]

I've had terrible luck with those black plastic attachments for jetting holes under concrete. It might be me, but I've had them fall off every time I've tried to use them. The glue holds because when they fall off, there is a black layer of plastic on the end of the pipe.

I use the cap method with the small hole drilled into the end. I don't really remember what size bit that I use, but something along 3/8's sounds about right. When I'm done, I cut off the end and use the pipe for what I'm doing and through the end away.

Eddie