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  1. #11
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    Default Re: sistering a new joist

    Quote Originally Posted by jkirk View Post
    if your using gun nails youll notice that gun spikes have teh same diameter as screws.. my engineer doesnt really care which we use as long as we draw the new joist tight to the old with hand spikes first. one top and bottom every 2'
    Diameter isn't the issue; it all comes down to shear strength. A nail will bend, a screw will snap; it has continuous stress risers built in. That's why it takes 1/4" screws (like timberlocks, etc.) to equal the shear strength of 16d nails.

    Casey
    Remove not the ancient landmark, which your fathers have set.

  2. #12
    Join Date
    Dec 2007
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    Default Re: sistering a new joist

    Once again guys, if he covers the full span, he does not have to mechanically bond the two joists together so it does not matter what he uses for nails or screws or if he uses any at all. It would be like a replacement joist only without removing the old one.

  3. #13
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    Mar 2008
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    nova scotia, canada
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    Default Re: sistering a new joist

    wood screws will bend but in a lamination the two pieces of wood wont shift so much that the fastener will be effected if the correct amount of fasteners are used and spaced correctly
    fire up the saw and make some dust

  4. #14
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    Sep 2009
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    florida
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    598

    Default Re: sistering a new joist

    Quote Originally Posted by keith3267 View Post
    Once again guys, if he covers the full span, he does not have to mechanically bond the two joists together so it does not matter what he uses for nails or screws or if he uses any at all. It would be like a replacement joist only without removing the old one.

    If the two joist are tight against each other without any mechanical bonding it might create a squeaking problem.
    Gizmo

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

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  5. #15
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    Default Re: sistering a new joist

    Quote Originally Posted by keith3267 View Post
    Once again guys, if he covers the full span, he does not have to mechanically bond the two joists together so it does not matter what he uses for nails or screws or if he uses any at all. It would be like a replacement joist only without removing the old one.
    Ok, this is just silly. He would have to re-fasten the entire flooring and sheathing to the new joists. You generally can't do that unless the finish floor is removed; hence the importance of fasteners. The joist isn't there to look good and lend emotional support...
    Casey
    Remove not the ancient landmark, which your fathers have set.

  6. #16
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    Mar 2008
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    nova scotia, canada
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    Default Re: sistering a new joist

    Quote Originally Posted by Sombreuil_mongrel View Post
    Ok, this is just silly. He would have to re-fasten the entire flooring and sheathing to the new joists. You generally can't do that unless the finish floor is removed; hence the importance of fasteners. The joist isn't there to look good and lend emotional support...
    Casey
    lol i love that last part
    fire up the saw and make some dust

  7. #17
    Join Date
    Oct 2012
    Location
    Houston, TX
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    249

    Default Re: sistering a new joist

    Actually - there is no subfloor, so fastening the floor to a new joist is no issue. The joist kind of is going in for sake of appearance and emotional support. I cannot handle the thought of a partially termite-riddled joist, even though the infestation is no longer active, and the emotional support kicks in whenever I go to sell the place 10-15 years from now and an inspector sees reinforcement done where not necessarily structurally needed at the time but done for the sake of maximum safety.

  8. #18
    Join Date
    Dec 2007
    Location
    Tennessee
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    1,419

    Default Re: sistering a new joist

    Quote Originally Posted by Sombreuil_mongrel View Post
    Ok, this is just silly. He would have to re-fasten the entire flooring and sheathing to the new joists. You generally can't do that unless the finish floor is removed; hence the importance of fasteners. The joist isn't there to look good and lend emotional support...
    Casey
    I think you just missed my point. In my first post, I recommended thru bolts, but this thread melted down into an argument over the advantages of one type of faster over another. The point I was trying to make was that in this case, it didn't matter.

    It would have been a lot more important if the sister didn't cover the whole span. Then it becomes more critical.

  9. #19
    Join Date
    Oct 2012
    Location
    Houston, TX
    Posts
    249

    Default Re: sistering a new joist

    Quote Originally Posted by keith3267 View Post

    It would have been a lot more important if the sister didn't cover the whole span. Then it becomes more critical.
    Ok, for the sake of my knowledge and since I love to ask questions, what if I only sistered from the beam on the perimeter to the beam in the center of the room?
    I'll say it is 7'6" span since I haven't measured exactly. That would put one end on a 6x6 beam and the "inside" end on a 4x4 beam.

  10. #20
    Join Date
    Jul 2010
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    SoCal
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    5,438

    Default Re: sistering a new joist

    Quote Originally Posted by function View Post
    Ok, for the sake of my knowledge and since I love to ask questions, what if I only sistered from the beam on the perimeter to the beam in the center of the room?
    I'll say it is 7'6" span since I haven't measured exactly. That would put one end on a 6x6 beam and the "inside" end on a 4x4 beam.
    This thread is going nowhere like this.

    To answer your last question, nail the two joists together.

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