I have recently did a total renavation of our only bathroom in our house.This included new copper pipes and new drain piping,new toilet,vanity and sink, and a whirlpool tub. The last item is why I want to put a full bath down in the basement and also the fact I am the only male in the house[women take forever in the bathroom].I am in the process of getting info together about installing a basement bathroom.I came up with the idea of a full bath because I Installed a new 50 gal. water heater which can definatly supply both bathrooms and using a posi-temp valve on the tub/shower downstairs as I did in the bathroom upstairs. My questions are about where to put the bathroom downstairs;tap into the main stack under the present bathroom or into the stack under the kitchen by the floor drain in basement, both have venting through the roof. The other concern is where to tap in the pipes for a drain. I wouldn't use the toilets that pressure flush up,the cost would use to much of the money for the project. The things I have in mind digging up the concrete and instlling a new stack and tapping into the new PVC stack with the three runs from toilet,shower,sink,under basement floor. My questions are;what size pipe would I use for the new stack and for each run to it or connect it with a tee. Also there is a question as to the toilet of sewer back-up,I have heard of check valve off of drain from bathroom which would prevent sewer back up.I am in the colection of information for this project and I am thinking of whether or not to do the whole job myself or to have a plumber come in to do the roughing in. I am skilled in plumbing,electrical,carpentry so this job is within my knowledge and skills. I would like any info you might have.