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  1. #1
    Join Date
    Oct 2012
    Location
    Houston, TX
    Posts
    304

    Default sistering a new joist

    Crawling under the house (pier and beam) I found a joist I do not like one little bit. A few of my joists have some minor termite damage that I plan to repair with bondo, but this one has some heavy damage on the bottom 4 inches for about three or four feet, bad enough that I could probably just rip the bad parts out by hand. The termites are gone(though I plan to spray anyway)and I want to fix this issue myself before I have the house leveled as I know this minor work will cost me less to do myself.
    Anyway, how do I compensate for the fact that my original joists are "true" sizes, as in rough-edged and actually 2x10 as opposed to 1&7/8 x 9&5/8? Do I buy a size wider (2x12) and notch at the support in the middle?



    The span will run the width of a 14' room with a 4x4 beam near the middle and 4x6 beams on the ends. I do know to use adhesive and a healthy number of decking screws.

  2. #2
    Join Date
    Sep 2009
    Location
    florida
    Posts
    598

    Default Re: sistering a new joist

    Get the next size joist up. If it's a 2x10 use a 2x12 and rip it down to the size needed. Glue together with liquid nails and screw together
    Gizmo

    Cut it 3 times & it's still to short.
    Inventor of the Miter Master Plus.

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  3. #3
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,836

    Default Re: sistering a new joist

    Personally I would notch the ends rather than cut a larger size down.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  4. #4
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: sistering a new joist

    if 2x10 is only smaller by 1/4 or so you can easily use those it saves you having to cut them down.. but you will need to make wedges to shim the new joist up flush with the tops of the existing joists on the ende.. then toenail as needed along the length of it to keep it flush. from there nail it off to have it fully laminated.

    using bondo doesnt do anything for hte strength of the woood. it just fills voids
    fire up the saw and make some dust

  5. #5
    Join Date
    Sep 2009
    Location
    florida
    Posts
    598

    Default Re: sistering a new joist

    Quote Originally Posted by JLMCDANIEL View Post
    Personally I would notch the ends rather than cut a larger size down.

    Jack
    Yeah that will work as long as there are no plumbing,elec pipes ect strapped to the bottom of the joist or in the joist space
    Gizmo

    Cut it 3 times & it's still to short.
    Inventor of the Miter Master Plus.

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  6. #6
    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    1,203

    Default Re: sistering a new joist

    Screws for sistering are not to code, unless signed off by an engineer. You have to use 16d nails.
    If you have to use screws, use Timberlocks or Headlocks,or Spax.
    Deck screws are a waste of time, as they lack anything close to adequate shear strength.
    So is the adhesive, IMO.
    It comes down to the fasteners, nailing(bolting) pattern and the bearing. An LVL is about 15% stronger than structural fir in the same depth.
    It's not going to be any fun getting a new straight joist into a situation with a center carrying beam in an old, saggy floor. For that reason I would not go any deeper in size than the original, and that probably means ripping down the new member.
    Casey
    Remove not the ancient landmark, which your fathers have set.

  7. #7
    Join Date
    Oct 2012
    Location
    Houston, TX
    Posts
    304

    Default Re: sistering a new joist

    Thanks for the input gents. Fortunately there is no sag in this particular spot in my floor, just preemptive action on my part.

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