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Measuring Floor Framing

steveeee | Posted in Building Code Questions on

i’m using this calculator
but floor framing length starts at 24′. i only have 18′ floor framing length and a 18′ span,  so the beam that come out seems way overkill.

does anyone know a calculator for a beam for a 18×18 floor?

thanks steve

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  1. Expert Member
    Akos | | #1

    Even if you use an on-line calculator, the building department will want a stamped drawing for the beam. You'll have to pay an engineer to size it properly.

    If you want to avoid that cost, I would check your local code, ours has tables for gluelam beams which could be used as a prescriptive option. An oversized prescriptive beam will be less cost than a beam plus stamped drawing.

    A simpler option is to skip the beam and clear span the space. 18' can be clear spanned for less cost than dealing with a mid span beam and footings.

    1. steveeee | | #3

      thanks, i was also thinking about just doing 2x12 clear span, at least for submission to the building dept and see what they say

      i did contact an engineer already but waiting for reply, things take forever these days

      BTW, do you have link to your code for gluelam beams?

      1. Expert Member
        Akos | | #4

        2x12 should be fine with bridging and subfloor glued. I would look at I-joist as well as the floor will be flatter and stiffer.

        Not sure how much it will help as I'm in Canada but here it is:

        Table A-11

      2. Expert Member
        MALCOLM TAYLOR | | #5


        2"x12" @12"oc c/w strapping and bridging meets our code, but it performs horribly.

  2. Expert Member


    You also need to be careful using Weyerhaeuser's sizing. They are making assumptions about the floor joists above based on their products which may not apply. Perhaps counterintuitively, the loading on the beam will increase if the spans are continuous, not broken.

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