When my cast iron sewer pipe comes out from under the slab there is a slit type hole in the top of the pipe before you get to the cleanout. It looks like it was made on purpose not like a crack in the pipe. It is about 6 inches long wider in the middle then narrow on both sides. I mentioned this to my neighbor and he said he had the same kind of hole only after his clean out. Is this supposed to be there and is there something that should be put over it to keep soil out of the pipe. I don't know what this is. The house was built in 1963
Thanks