Replacing a basement drain
I had an old rusted apart 9x9 drain assembly in the floor that was more of just a cover than a sanitary drain. It let odors and sewer flys in the house. There was a rubber plug in it to stop that, but guess it didn't work too well. I want to put a bell trap drain in it to stop odor & critters. It's terra cotta pipe with an inch or two of cement on top. The whole drain assembly plate was 9x9, but the actual drain hole is 6" with a 1" rim and the terra cotta pipe inside is 4". Its about 2" deep to the top of the pipe.
I bought a 9x9 PVC drain assembly but the line on it is 4", and thats the same size as the pipe, so it doesnt fit. I do not want to dig up the floor to replace this drain, and a smaller size would be OK. Can I put in a 6x6 drain and just cement it in place? Since a 6x6 it will only be about 3" how do I seal the line since the terra cotta is 4"?