Eplumber: Thanks very much. I will have to think about how to install a line in concrete and yet get to it for replacement; maybe just running it through a larger ABS pipe and having the drain in a box will suffice. Are you familiar w/ these gizmos? http://www.canplasplumbing.com/plumbing.aspx?categoryID=867
Or these? http://www.trapguard.com/
The present house, built in '80, has cast iron pipe and covers, so I don't think either of these would work here. The new house will have something more adaptable/adjustable.
Or these? http://www.trapguard.com/
The present house, built in '80, has cast iron pipe and covers, so I don't think either of these would work here. The new house will have something more adaptable/adjustable.