I've got a two-car garage (4-inch concrete slab on grade) that I'm turning into living space. I want to put a bathroom out there but I need to get plumbing through the floor. I didn't think it was possible. I had a contractor come over and take a look. He said no problem. We could just cut a 6-inch trench in the concrete halfway-across the garage. This did not sound like a good idea to me. Is this generally a safe thing to do while keeping the integrity of the slab intact?
The garage is on a slab, but the rest of the home is on a crawlspace. So we'd just need to cut the trench from the middle of the garage to the wall of the crawlspace to tie it in with the plumbing.