venting my new attic bath

[Don]

Im finishing out my attic as a bedroom and bathroom..I need to re-route a 3 inch cast iron main stack pipe from the downstairs bath( it goes straight up thru the roof in the middle the new attic bathroom under construction and I also need to run a separate 2 inch vent thru the roof for the new attic bath..a friend told me..I should put in something called ( studer vents ) ?...he says he has them in his restaurant...they dont have to go thru the roof..I've never heard of them..apparently it has a one way air valve or something..that prevents sewer gases from escaping...any opionions about this type of venting?..Thanks

[jadnashua]

These are only used where the drain is a long way from any available place where you can vent normally, and it still needs to have a real vent somewhere in the house! You often see them in places like an island sink where you don't have any way to hide a vent line up fromthat location. I doubt code would allow them in your situation. You can move the existing vent out of the middle of the new room. You should also use a new vent (or connect to the existing one - easier to do a new one since you are right there near the roof, or you run into 'wet venting' which can get messy) for the new bathroom. Connecting the drain into the existing one also requires some work. I'm not a pro, so can't give you the details. Basically, you don't want to be dumping stuff down the vent line from below (wet venting) without following all of the rules, or you run into problems.

[hj]

Instead of that friend, I think you need one who is also a plumber. Adding a second floor bathroom can have effects on the existing plumbing if it is not done correctly. Getting the pipes to fit between the floor and the ceiling and still comply with all the requirements can also be a challenge. You cannot always just do it the way that things fit.