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Spacing of Sill-Plate Anchors

idahobuild | Posted in General Questions on

Hello All,
Code seams to call for min. 6′ centers for PT, sill-plate, hold-down anchors (plus those at openings/edges). Any value in moving them to 4′ or 5′ centers?

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  1. Expert Member
    ARMANDO COBO | | #1

    See IRC R403.1.6. Most wood sill plates are usually anchored to the foundation with minimum ½” anchor bolts (5/8” are better) spaced NOT GREATER than 6 feet on center. Bolts should be inserted into concrete at least 7” and located in the middle 1/3 of the plate’s width. You must tighten all bolts with nuts and washers. Install bolts within 12" of connecting walls, corners and openings.
    Depending where you live, site and soil conditions, especially with Seismic zones C & D and even certain length of walls, you may need your foundation engineered.

    1. idahobuild | | #2

      I am trying to find an engineer, that is licensed in Idaho, to review the plans. I am in Seismic C. I'll start with 6 foot center max (and other 'per code' references) and see what happens.


  2. kbentley57 | | #3

    Many times they end up less than 6' spacing on average due to all of the other requirements on them, as Armando mentioned.

    Don't neglect the hold downs! Anchor bolts are there to provide the shear, but not (necessecarliy) for uplift or tilting. Those may also provide shear resistance, depending on the style. If you search youtube for the APA channel, they've actually got a really good series on portal frames, anchoring, and other topics.

  3. idahobuild | | #4

    Thanks Kyle.

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