Hello All,

I am currently finishing out the basement of a clients two story home and I have a question involving venting the bath.    This system will require a sump pump and basin to remove the sewage.  The waste lines and basin are already installed in the slab and the toilet is about 3′ from the basin the farthest fixture is the shower which will be about 8′ away with a vanity sink between it and the basin.   I can find no capped stup for the vent stack or easily accessible stack, neither could my plumber. 

Now for the question, my plumber suggests that we run the basin vent between the joists through the outer wall where we will cap it with cap similar to a screened shower drain.    This will fall right below a deck.   He assures me that this configuration will pass inspection.   My concern is with odor.   Is this configuration going to be release sewer odor out onto the deck while clients are out grilling dinner, not a good scenario?   He says that there will be no problem with odor because very little waste in sewer and when the unit is in use the vent will actually be pulling air into the vent. 

What do you guys think, is this a recipe for disaster?   Any other ideas for venting this basement?