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Another deck ledger detail question

JoeNorm | Posted in General Questions on

I didn’t want to hijack the other thread going on this topic so I thought I would create a separate one.

I have a second story deck to install and in preparation I installed a “belly-band” in the siding at the proper location. Since it served as a part of the siding for the time being it is structural Doug Fir, but not pressure treated. I flashed it properly to prepare is as a ledger.

Now it’s time to install the deck. I’m thinking the best approach is to install a second ledger with spacers right onto the “belly-band.” This would be PT.

But would it be wrong to attach joist and hangers directly to the bellyband if it’s properly flashed? I am planning to use the Simpson tie that can be attached with a lag screw into the top plate. Maybe this approach would not satisfy code?

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Replies

  1. Expert Member
    PETER G ENGLE PE | | #1

    Connection details aside, you should rethink using an untreated ledger, unless it is completely covered by siding and WRB. Once you add a second layer of treated ledger, the inner one can trap moisture and may have little ability to dry. This is one of the most common causes of deck failure, and people get hurt all the time when decks fall off of buildings.

    There are plenty of details available, but the most common approach is to have the rim joist (band joist, etc) placed normally at the end of the floor framing, below the wall plates and studs and well fastened to them. The rim joist is fully protected by WRB and flashings against any moisture. I prefer to have a layer of self-adhesive flashing covering and protecting it as well. Then, the treated deck ledger gets fastened to it, with the ledger flashed as well and the ledger flashing properly integrated with the wall WRB to direct all water to the exterior. The joists then get fastened normally to the ledger. Use of lateral tiebacks depends on deck design and local code, but should not be skipped if necessary.

    These are standard details. If you intend to deviate from them, you will need to get an engineer involved. If you haven't already got it, a review of the DCA-6 deck code will help your understanding immensely. Finally, if you post a sketch of your proposed design here, we will be glad to provide feedback, but the advice is worth what you pay for it. If you are going to bet your life on free advice fr0m the internet, that's up to you.

  2. JoeNorm | | #2

    Thanks for the reply.

    The board (2x10 rough sawn fir) is acting as siding. It's attached directly to framing and is flashed into(lapped) the building WRB so it doesn't catch water on its top side.

    If I apply another PT board with spacers I don't think there is a place for moisture to catch. Perhaps if I didn't use the spacers it would be more of a potential problem.

    The better approach sounds like it would have been to install the PT ledger in place of the Fir bellyband.

  3. walta100 | | #3

    After so many news worthy stories about decks collapsing and the resulting deaths. Most locations have chosen to update the requirements for decks supported by the house. The new lateral load requirements require opening up the ceiling in the home to connect the houses joists to the decks joists. Generally it costs less to build the deck as self supporting than to fulfill this recruitment. With this separation most of the leaking flashing and rotting wood problem disappear.

    Walta

  4. JoeNorm | | #4

    Simpson also makes the DTT1Z to avoid opening the ceiling.

    https://www.finehomebuilding.com/2015/05/04/dtt1z-deck-tension-tie

    1. Expert Member
      MALCOLM TAYLOR | | #5

      Joe,

      The disadvantage of the DTT1Z is it penetrates the top plates - and so do hidden pipes and wires. Be careful where you locate them.

      I don't know what your code says about using non-PT wood for the ledger. It's something that will work, until it doesn't.

      There isn't much point adding another ledger to the existing one unless you could flash across the top of both of them. Two ledgers separated by spacers would act the same as having just the one. My preference is to flash the ledger as you have done, but install the deck joists 3/4" higher, so there is a gap for debris and water to drain.

      1. JoeNorm | | #6

        I agree shooting a lag into the dark is not a great idea. Fortunately this is my personal residence that I built so I know where every pipe and wire is/is not.

        Good point about there being no point to adding a second ledger, I think you're right.

        Would it be local code regarding whether PT is required? That is not spelled out in national code?

        1. Expert Member
          MALCOLM TAYLOR | | #7

          Joe,

          "I know where every pipe and wire is/is not." Perfect! That connection looks a lot simpler than the threaded one usually used.

          It looks to me as though you have a few choices for which wood to use, but I don't know enough about your local codes to comment usefully:
          https://www.awc.org/pdf/codes-standards/publications/dca/AWC-DCA62015-DeckGuide-1804.pdf

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