Replies

1. 
   suburbanguy | Feb 15, 2020 06:07am | #1

   Purchase a diamond concrete blade for your 8 in "skillsaw". I've cut my basement floor and a few landscaping paver jobs with mine. Have a friend hold a garden hose with a little water dribbling from it (or a bucket of water with a small hole in the side) to reduce/eliminate the dust. The water will cool and extend the life of the blade. The dust will fly everywhere if you don't, and the vac will get barely any of it. You really don't want to be breathing that dust. Lift the peel and stick tiles before tackling the concrete. Be VERY careful of water around the tool and the electrical plugs. Be sure to plug into a GFCI for added safety.--Replace the existing one that you plan to use with a GFCI, if necessary.

1. 
   unclemike42 | Feb 19, 2020 04:29pm | #11

   The tiles come up fine after warming them up a bit. any suggestions for the glue left behind?

2. 
   cussnu2 | Feb 15, 2020 09:12am | #2

   I am normally not one to get overly cautious or regulatory but you should, at a minimum, make some effort to determine if that tile is asbestos before you going sling dust from it all over your house...

3. 
   calvin | Feb 15, 2020 09:48am | #3

   How thick is your slab and is the pipe close to the foundation Wall?

1. 
   unclemike42 | Feb 15, 2020 03:47pm | #4

   I do not know how thick the slab is. want to guess 3-4 inches. house was built in 1972,

   broken pipe is actually under a block wall which separates the basement from a crawl space. have to get under the slab to join new pvc to what hopefully is solid pipe.

   Cast Iron above the break takes a sweep from horizontal to sweep to a five foot vertical drop, then another sweep to the pipe under the floor.

   a fella I paid $600 to retrieve a rag I dumped down the second floor toilet banged on the rag and pipe with a pretty beefy snake (on wheels thumped up the stairs) for 20 minutes or so to get the rag back up. I think he cracked the pipe, but of course the story is, pipe was almost 50 years old , could have been ready to go any time.... and an offer to replace for $4k.

4. 
   suburbanguy | Feb 15, 2020 04:18pm | #5

   Highly unlikely that it is 3-4 inches thick. More likely 2 inches or less. Drill a hole in the vicinity and you'll know for sure.
   I have no doubt that the block wall is a structural wall and I wouldn't disturb it. Can you make the new connection in crawl space and bring the new PVC pipe through the wall (back into the basement) and therefore avoid disturbing the foundation?

1. 
   unclemike42 | Feb 15, 2020 06:29pm | #6

   There is room around the existing pipe (hole in the block wall) I have not dug down to verify where the footing is, (or the bottom of the block wall), but it seems the pipe is routed above the footing for the wall, (and under the basement slab)

   I do plan to drill the corners of the area to remove. this will let me verify the slab depth. (three feet on a side seems a good plan to leave enough room to dig around the pipe) The saw manual says to make cuts in concrete an inch and a half at a time, so two or three passes

   seems like I can leave the hole six or eight inches from the wall. (block, then 2x4 studs and paneling)

   There is a foot or so on the crawl space side, then four or five feet of dirt. I may need to pass the new PVC from the basement side, and start joints in the crawl space. will have to be careful to keep them clean and make good joints.

5. 
   unclemike42 | Feb 17, 2020 08:00am | #7

   Now I am thinking of buying a 5 inch grinder with diamond blade and dust catcher rather than renting.

   combo is around $175 vs $150 for rental and 14 inch blade.

   will drill a couple holes first to get an idea how thick the slab is.

1. 
   suburbanguy | Feb 17, 2020 09:53am | #9

   A grinder with a 5 inch diamond blade is not the right tool. You'll only have at most, 1 1/2 inches of cutting depth. (They use a fairly large centre nut. ...and the housing will get in the way.) Like I said, get a blade for your Skillsaw. The 7 1/4 inch blade they use will do the trick. You'll have about 2 1/2 inches of cutting depth. Even if the basement floor is a little thicker, you'll easily be able to crack the remaining bit. I used one to install a backflow valve in my basement floor drain. Had to cut around the drain to install it. The Skillsaw cut completely through the concrete floor.

6. 
   florida | Feb 17, 2020 09:02am | #8

   Betting that the floor is only 2 inches is a losing proposition. No one ever complained that their saw was too big for the job. Trying to use a grinder will make you cry. Forget the vacuum, it won't do a thing except clog the filter. Cut a big hole, the holes is never big enough. wear a dust mask, earplugs and over the ear protection as well. If you have enough saw and water it won't take you 10 minutes to cut out the hole. Then go back and cut the slab into smaller pieces so you can get them out. A hand truck makes it easy to move the pieces.

7. 
   unclemike42 | Feb 19, 2020 04:27pm | #10

   here is a photo of the offending pipe from the crawl space

   
8. 
   unclemike42 | Feb 19, 2020 04:30pm | #12

   I have the area cleared, and will put up a plastic wall in the morning, before digging into the concrete

9. 
   unclemike42 | Feb 24, 2020 05:31pm | #13

   Turns out the slab is more like 3 inches. I cut deeper and sliced the cast iron. so had to make the hole a little bigger to get to solid pipe for the transition to PVC. the saw did clog the shop vac filter very fast. I rented a 14 inch concrete saw from the local home depot. and used my Bosch XDX plus rotary hammer to break it up. Thanks for all the helpful hints.

   I think I will need to cut into that block to get the new pipe in place.

   the crawl space is on the other side of the wall

   That section of pipe under the open floor has two joints in the CI. (in addition to the one broken and leaking under the wall) Is there a minimum distance from a bell end for a cut and transition to PVC? how about minimum length before pipe enters a rubber gasket joint into the bell?