Ask Me Help Desk - Remodeling with Slab Foundation

Quote:

Originally Posted by kingcon

I want to remodel my house with a slab foundation. To keep things simple I'm trying to re-use the existing plumbing & gas (in kitchen) connections. I also want to add a bathroom in what is currently the garage. It has laundry hook-ups for washer & dryer so I'm thinking I can use those, but I'm not too sure how to go about it. I'm an interior designer with a project manager in construction background but I've never worked on a home with a slab foundation before. I'm used to being able to see the pipes, drains, etc. Any advice would be appreciated as I am in the planning stages right now & want to keep my costs & upheaval to a minimum. Thanks.

In my area all our houses are on slabs. First off, you're not going to be able to use a 2" laundry drain line to pick up a bathroom group drainage. You'll need to go to 3 or 4" for the main branch and 2" for the lavatory and tub/shower drains. Let me show you a typical, (in my area) bathroom group rough in. This configuation only uses one vent for the entire group.
4" ,(under cement and basements) 3" (on first and second floor) from the toilet to the main. The lavatory to connect to the toilet drain line and vent to the roof or revent back in the attic to a existing roof vent. The tub/shower to connect to the lavatory drain line and be wet vented by it as will the toilet. Be advised to always check local codes before changing or remodeling your drainage system.
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