PVS Repair Coupling VS. Fernco Coupling

Hello everyone.

I am current in process of converting my empty basement into something more enjoyable. I have reached the point where I want to put up the walls of the bathroom. Before I can do this I need to put in the rough in plumbing connection for the bathroom. I have to cut the basement floor to get to the main sewer line to join the drain lines from the bathroom to the main sewer line. Once the floor is cut and I have access to the main sewer line I plan on inserting a necessary Tee fitting into the main line. My problem is this, there will not be any play with the main line to get a tee fitting place and I need to use some type of coupling. What type of coupling? If I use the Fernco coupling can this be put into the ground and cemented over. And is there anything special that needs to be done to it before I do so. Or do I user a PVC repair coupling. However I read nothing but hoar stories when people have tried to use this with the glue drying to fast and not being able to get the coupling in place. That or they get it in place but it ends up leaking. Other people thoughts and experiences are welcome at this point.

Underground, where both ends of the pipe are properly supported to maintain alignment, the rubber coupling is allowed. You don't want a T fitting there, you probably need a Y. You may also be required to provide a cushion around the pipe where it comes through the concrete. PVC expands and contracts with temp changes, and a cushion there should prevent potential stress cracks in the material.

jadnashua said:

Underground, where both ends of the pipe are properly supported to maintain alignment, the rubber coupling is allowed. You don't want a T fitting there, you probably need a Y. You may also be required to provide a cushion around the pipe where it comes through the concrete. PVC expands and contracts with temp changes, and a cushion there should prevent potential stress cracks in the material.

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Personally, allowed or not, I would never bury a Fernco rubber coupling under cement. Use a repair coupling, lots of glue and work fast.

Thank for your advice. I understand how water flows and that the least path of resistance is needed. I understand about the Y adapter. When I said Tee connector I meant some type of 3-way connector. What type of 3-way connector I use will be based off what I discover when I cut up the cement and expose the main sewer line. In want a 3-way connector that promotes the flow of water in the direction that the main sewer line natural flows. This much I understand.

What I am I still not clear on the connector type. Some people say go with the repair PVC coupler and other say go with some type of Fernco coupler. I feel cemented PVC coupler is far better that having a rubber coupler held on with a clamp that over time could rust or corrode off. I have found slow setting PVC cement that takes 3-4 time longer to set then normal cement. This should allow me to get the PVC coupler in place before the cement hardens and locks the coupler in place. I think I am going to try this first, let the cement dry and leave the main sewer line exposed for a week and look to see if the coupler leaks. If it does then I can remove it and then use the Fernco coupler.

highdm said:

I have found slow setting PVC cement that takes 3-4 time longer to set then normal cement. This should allow me to get the PVC coupler in place before the cement hardens and locks the coupler in place

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I don't see that working out for you. I don't think you should plan on having time to reposition things.

The PVC repair coupling is best on a theoretical level, but not so on a practical level. There is little tolerence and you have to work fast, whatever cement you use. It is easy to not get the coupling centered. I would use either the shielded or all rubber coupling. They are easy to work with, especially the all rubber ones. If you get an approved coulping the clamps will be high quality stainless steel and won't corrode off.

Rubber and stainless steel do not "rust". I doubt that you have the experience needed to properly install a repair coupling. It must be perfectly aligned and you only have seconds to position it over the cut before it fuses into place.