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Community and Q&A

Screws for Sistering a Stringer

derekr | Posted in General Questions on

I have a knot at a weak point in one of my stingers that I didn’t notice and was told I should sister a 2×6 to it

what size screw should I use #8 9 or 10?
and should they be 2.5 inches or 3 inches?

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Replies

  1. kbentley57 | | #1

    I think you're overthinking it!

    Simple 3" nails in a good tight pattern will work fine. as will pretty much any screw that's between 2.5 and 3".

    1. derekr | | #2

      Ok thanks I’ll just get #10 3 inch screws

      The stairs are already together so I need to use screws I don’t have room for a hammer

  2. DC_Contrarian_ | | #3

    Use deck screws, not drywall screws. Drywall screws are brittle and snap off.

    1. derekr | | #4

      Any deck screws or are some better than others, i was looking at spax

      I wish I would have noticed this knot before I put it all together, it can’t be seen on the other side though guess that’s why I didn’t notice it

      1. kbentley57 | | #5

        Any pack of the 3" #10 construction screws will be fine. The spax are great, I'd used them or GRK whenever I get the chance.

  3. derekr | | #6

    I forgot I put blocking under the stairs for my posts which means I wont be able to use a full 2x6, I will have to cut it down 1.5 inches to 4 inches, will that be enough or should I put it on the outside of the stairs for the full board?

    Outside of stairs I could do 5.5 inches, inside of stairs I’ll only be able to do 4 inches is that good enough

  4. kbentley57 | | #7

    4" is plenty.

    I'm curious about the trex tread on top - is there a solid board underneath?

    1. derekr | | #8

      I put that there to attach my post on top
      That’s why I can only do a 4 inch sister board instead of 5.5 inch

  5. Expert Member
    BILL WICHERS | | #9

    I would glue AND screw your brace here. I like PL line of polyurethane adhesives. The glue ends up doing most of the work this way, with the screws mostly just acting as clamps to hold things together while the glue cures.

    I agree with the others to use deck screws. I'd probably use structural screws if I wasn't also using glue.

    Bill

    1. derekr | | #10

      I’m getting the strongest liquid nails they make is that good enough or I need a different brand

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