We are remodelling, actually we have added a first and second floor to an existing basement. There was never a first floor on the property, the house was only a basement, built in the 70's, never finished for whatever reason, it sat 3' out of the ground and 6ft in the ground, built with military grade concrete. The "basement" is totally finished, has 3 bedrooms, living, dining, kitchen and bathroom with one toilet. This is a rural property. It has a septic system fed from the house with a 4" PVC pipe. We have had the septic dug up and all is now well with that system.
So now we have added a main floor and a second floor loft. We are doing this almost entirely ourself. The main sewer pipe enters the building in the basement toilet and the existing basement toilet is fed into it, and then the pipe continues up through the roof. At some point the 4" pipe transitions to a 3" pipe which we have yet to discover where. What we have now is the 3" vent pipe going up through the main 1st floor and we have temporarily passed it through the wall to the outside.
What we planned to do was to use this stack to connect 2 toilets on the first floor, and one 2nd floor toilet, then continue the stack through the new roof as a vent.
After reading some similar posts here, I get the impression that this is not the way to do this.
Will we need to create a whole new stack from the septic to feed the new floors? Is there any way around this? The idea of busting through the 9" concrete basement floor and digging a new channel to the septic is daunting.
what you "have" to do is design a correct DWV system, and that is not something we can do from an E-mail.
Licensed residential and commercial plumber