Welcome to Q&A for Home Maintenance Q&A section, where you can ask questions and get answers from me and other members of the community.

Spam, self-promotion, questions with abusive, inappropriate language, and irrelevant questions will be deleted.
All of the questions are moderated!


You'll be notified when your question is answered. Please reply with Feedback to share whether a solution worked or didn't work. Thank you!

Connect on Google+
Find on Google+ Local

For a garage addition, can I run a 4" main through a 2 x 6 wall to connect with the house main

0 votes

I am converting one side of my two car garage into a studio that will have plumbing for a full bathroom and kitchen sink. As the studio will be on the far side of the garage, I will need to run the main sewer line across the remaining garage space and wanted to run in a wall versus jack hammering up the concrete floor. I would also need to raise the studio floor to accommodate the plumbing.

Perhaps I only need to run a 3" to the main?? It will be 15' from the bathroom and kitchen studio addition

Thank you

Mary

asked in Interior Walls by return6 (140 points)
Share this question on your favorite network.

1 Answer

0 votes
Hi Mary,
3’ diameter drain is a minimum required to handle a toilet and sufficient for a full bathroom (for gravity systems). You other option would be to use low profile "Up-Flush" sewage lift pump system (example: http://www.accentshopping.com/product.asp?P_ID=150032#tabtop). It supports two additional connections like sink and a shower / tub and uses 2” diameter discharge pipe.

There might be a problem with 2x6 framing of your wall. If this is a bearing or exterior wall you can only drill a hole in the stud up to 40% of its width (no closer than 5/8” to the face of stud) or notch 25% of it. 60% boring is permitted on bearing walls only if you double the stud and you cannot go through more than 2 doubled parallel studs. For non-bearing walls, 40% notch and 60% boring is OK for the entire wall.

With 2” diameter pipe bearing / exterior wall wouldn’t be an issue.

For 3” or larger gravity drain you need minimum slope of 1/8” per foot. Don’t forget venting of this system and make sure you always check your local code requirements.
answered by darekrudy (21,730 points)
...