Follow Fig. B, for the new drain/vent plan. The new shower drain is vented separately into the main stack (Photos 10, 12 and 13). Most bathrooms have the main stack positioned directly behind the toilet. The wall-mounted toilet shown here cannot be positioned directly behind the stack because there’s not room for the necessary elbows. If your stack is more than 12 in. to the side of the existing toilet, you can keep the same location for the wall-hung toilet. But if it’s directly behind it, you’ll need to swap the sink and toilet locations like we did.
Guest bathroom: This is a full-service bathroom, with sink, toilet, and shower or shower/tub combination, but one that is used sporadically when guests visit. In empty-nest homes, a kids' full bathroom might be converted to a guest bath. Because guest baths get only occasional use, many people choose to use economy fixtures and materials, which can greatly cut costs. And because this is a secondary bathroom, you can take your time remodeling it, which also saves cost.