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16′ clear span for deck beam

joenorm | Posted in General Questions on

I’m looking for ideas to get a 16′ span between posts for a deck support beam. 8′ joist length from the ledger on the house with a 2′ cantilever.

I have a septic tank in-between that I don’t think I can put a footing over the top of.

All the span charts are pointing to either a glulam, LVL, or steel. I am leaning away from steel to avoid the cost and hassle of introducing a new material. So the glulam or LVL would have to be treated for exterior use.

Has anyone addressed a similar span recently? What solution did you come up with?

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Replies

  1. Expert Member
    MALCOLM TAYLOR | | #1

    Joe,

    I think I remember you saying you didn't have permitting where you are? If I've got that wrong, you should confirm you can do this. Our bylaws don't allow decks over septic tanks, no matter what the clearance above.

  2. joenorm | | #2

    Good idea. I will look into this. Thanks

  3. joenorm | | #3

    This will be a second story deck and not hinder access to the tank at all so the question still stands about what type of beam to look at for a long span. Pacific Woodtech LVL is looking promising.

  4. gusfhb | | #4

    PT triple 2x12 maybe with glue and screw PT plywood in between. Need to do the engineering, but hard to believe it exceeds that. Other option is similar beam from house to post and joists spanning the 16 foot

  5. graham78 | | #5

    looks like 3 count of 2x12 pwt lvl could span 16' depending on your snow load.

    1. joenorm | | #6

      Yes, but I believe that is a dimension of 3 and not a count.

      1. graham78 | | #7

        2 count will work with a combined load 0f 50psf - L/360

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