Hi... I will soon be adding a bathroom to my basement.It will consist of a toilet, vanity sink, clothes washing machine and a corner stand up shower.My existing main vent stack is 3 inch copper venting through the house roof.Two feet from where the vent goes into the cement basement floor to join onto the main sewer is a three inch toilet closet flange.This also joins the main sewer.I plan on removing the toilet flange and adapting 3 inch ABS plastic sewer pipe as a sewer header for this project.The floor in this bathroom will be elevated to provide a proper grade slope for the 3 inch plastic sewer and traps.The sewer pipe will run about the circumference of the basement wall above the cement floor.Roughly after 10 feet of run the 3 inch pipe comes to a basement wall corner:
A) at the corner should I place a 90 elbow or are two 45's better?
B) since every trap requires a vent can I place them all on a common header and tap into an existing dry vent line.In this case 11/2 ABS plastic?
Thank You
Derek

Hi... I will soon be adding a bathroom to my basement.It will consist of a toilet, vanity sink, clothes washing machine and a corner stand up shower.My existing main vent stack is 3 inch copper venting through the house roof.Two feet from where the vent goes into the cement basement floor to join onto the main sewer is a three inch toilet closet flange.This also joins the main sewer.I plan on removing the toilet flange and adapting 3 inch ABS plastic sewer pipe as a sewer header for this project.The floor in this bathroom will be elevated to provide a proper grade slope for the 3 inch plastic sewer and traps.The sewer pipe will run about the circumference of the basement wall above the cement floor.Roughly after 10 feet of run the 3 inch pipe comes to a basement wall corner:
A) at the corner should I place a 90 elbow or are two 45's better?
B) since every trap requires a vent can I place them all on a common header and tap into an existing dry vent line.In this case 11/2 ABS plastic?
Thank You
Derek

Before I venture an answer let me ask a question or two. How many linear feet are you running the new sewer pipe and how many inches of drop are you planning to allow?

A) at the corner should I place a 90 elbow or are two 45's better?
Two 45's or a sweep would be better then a 1/4 bend in the corner.

B) since every trap requires a vent can I place them all on a common header and tap into an existing dry vent line.In this case 11/2 ABS plastic?

Yes you may. You will need only two vents if you connect the shower to the lavatory drain line where it will be wet-vented. The leaves the washer and the lavatory to be revented back to a dry vent.
Good luck, Tom