Hi guys,

I'm putting a shower, sink, and toilet in my new basement bathroom and am trying to save a few bucks with the plumber by cutting the concrete myself. Question is how deep do I need to make the cut and what slope is sufficient to prevent waste from backing up? Or am I just better off contracting the whole thing to a plumber? And is there anything else I'm not considering?

About the house: new house (2004), drain exits below the slab, probably 4" slab but unknown until I cut.

Here's the proposed layout.

Thanks all.

D

Your layout looks OK except for a few minor changes. For the 90 degree turns I would substitute 45's or long sweeps. Make your drain from the lavatory 2 inch increasing to 3 or 4 inches to pick up the toilet. Your slope will be 1/4inch fall for every foot bof drain line. I would check local codes to be sure a wet vent's allowed on the shower. You are venting the lavatory aren't you? Good luck, Tom