who knows plummbing?

Question

i am changing a bathroom around in a basement and moving the toilet where the shower is and building a new shower 4 feet past where the toilet is i assume the old drain to the shower is a 2" line if i just replace that with a 4" will everything still be vented and will i have any problems with the exsiting 4" line where im putting the shower.( will the drain be too big for the shower fitting or will there be any other issues with odour)

Answer 1

What I know is, the current toilet drainline probably ties into the main drain stack for the house. Using this line for the shower will not work since the main line is also the vent and you would be using a reducing fitting from 2" to 3 or 4" for the shower drain. It will not drain properly unless you can find an eccentric reducer. Moving the toilet 4 feet will remove the venting so it would need a "backvent" installed. Without proper venting, the fixture traps will be sucked out and allow sewer gas to enter the house.

Answer 2

In that you must have 15inches from the center of a toilet drain, to the finished wall on each side of the toilet, I doubt that you simply put the toilet floor flange exactly where the shower drain was, but you need to increase size to at least 3" so it should not be a major strain to relocate it a few inches. You will want to provide a vent for the new shower location, this is easy though, bring up the vent inside the wall and run it to the existing vent horizontally. The new shower drain can be 2inch and be connected to the new 4inch serving the toilet.

Answer 3

Unless there's P-TRAP or T-TRAP before main pipe you'll not have odor .From small size to largest is OK . But from largest to small size you'll experience slow draining in some cases air bobble.