Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Can I drill a 3 inch hole for plumbing through a 2 x 11 inch joist?

Can I reinforce the joist by adding 2 more 2 x 11 inch boards on either side? I'm not concerned with building codes.

11 Answers

Relevance
  • 1 decade ago
    Favorite Answer

    Just like they're saying.

    Sure.

    This is plumbing though and you must have fall (slope) in the pipe. Are going through multiple joists? Then you have to start above center and slowly drop in each following joist. If the pipe will elbow after the hole and travel in the bay, you still may have to drill above center.

    Just stay as close to center as you can. That depends on how far the pipe travels horizontally. 1/8" of fall in every foot of run is more than enough.

  • Anonymous
    1 decade ago

    The hole must be drilled near the vertical center of the joist. Building codes will specify the maximum diameter hole for particular sized joists.

    Bored holes are limited in diameter to one-third the actual joist depth, and the edge of the hole cannot be closer than 2" to the top or bottom edges of the joist. So a 2x11 is really more like 10.5 inches, which means the maximum hole would be 3.5".

  • 1 decade ago

    As long as you are just drilling through 1 joist it should'nt be a problem but, why would you want too? Wheither your installing a tub, sink, or washing machine drilling only 2" to the left or to the right of the joist will not be a problem. your trap either "s' or "p" trap above or below the floor gives you enough room to avoid the joist and still connect the drain. good luck

  • 1 decade ago

    if you stay in the center you can drill,even by code a hole one third the size of the joist without reinforcement

  • How do you think about the answers? You can sign in to vote the answer.
  • 1 decade ago

    I believe if you combine "kokopelli's" and "jason m's" advice, you'll have a fairly accurate answer. You can confirm this by contacting the joist's manufacturer or by reviewing the topic in your region's local building code. These can generally be found in the reference section of your local library.

    Source(s): 10 years experience as a framer, finishing carpenter and renovator
  • 1 decade ago

    how do you get 1/3 of the size for a hole.. lol a 2x10 can have a 1 1/2 hole in center by code. over the years ive seen some crazy stuff thats held just fine..

  • 1 decade ago

    staying in the center of the joist is important. if you have to move it to the top or bottom sister the joist with another one.

  • Anonymous
    1 decade ago

    Yes, but you have to drill it through the 11" side, not the 2" side.

  • 1 decade ago

    You can do as most of these answers say, but I would hang it instead. You hang it with the flexible metal that has all the holes in it, just don't get aluminum if you are hanging galvinized pipe.

  • 1 decade ago

    Sure you can- just get a 3in hole saw and start drilling. I would bolt the other 2 2X11's first though.

Still have questions? Get your answers by asking now.