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Community and Q&A

Location of Deck Ledger Bolts

DerekR | Posted in General Questions on

I’ve already bought all my lumber for the deck, i went with 2x12s since that’s what my sub floor was

i wasn’t thinking that I need drop the ledger 2 or 3 inches so that there would be space for deck board and 1 inch step up to the door

if i drop it 2-3 inches then the bottom of the ledger is going be 1-2 inches past my sub floor and over my foundation, will it be ok to drill my bolts 4-5 inches from the bottom of ledger? And the other bolts 2 inches from the top? Or did I just waste about 1,000$

one of the decks is about 29 feet wide and will come out from the house 12 feet or so

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Replies

  1. Expert Member
    NICK KEENAN | | #1

    This is a highly technical subject. But you want the spot where the deck joins the house to be highly waterproofed, if water gets into that rim joist and causes rot it can lead to the deck collapsing. At a door, it's easier to waterproof if the deck is lower than the interior finished floor height, then you can have vertical flashing above the ledger. If you have a step down, anything over 3/4" and less than 6" is a tripping hazard.

    How to attach the ledger to the rim joist is a whole discussion of its own. Sometimes it's easier to put posts along the foundation and not have the deck supported by the house.

    1. DerekR | | #3

      I may just make the deck free standing and not attach it to the house that would solve my problems, I’m not sure how to get it right up against the house though since my posts would be right on top of footings and only a few inches from the foundation, it’s also 4 feet tall

      1. Expert Member
        NICK KEENAN | | #5

        Put the posts 2-3 feet away from the house. Run a beam between the posts. Set the joists so they rest on the beam and overlap up to the edge of the house. Leave a gap between the rim joist on the end of the joists so water can't accumulate there.

        If you don't get snow that should be enough to keep rain from getting under the door. If you get snow you want to step down 6-7" so if snow piles up there it doesn't melt and get under the door.

        I hate to be a nag, but you should have figured this out before buying the lumber. Decks look simple but they're complicated.

        1. DerekR | | #6

          I actually just remeasured and it looks like the 2x12 ledger would only have to drop down 1 inch in order for me to have 3/4 inch step from the door, so I may be fine if I attach to the house, so my bottom bolt on the ledger will only be 3.5 - 4 inches from the bottom and the top bolt will be 2 inches from the top of the ledger

          I knew my floor joists were 2x12s so that’s all I was going by didn’t think I could go smaller

          I got 14 inch vinyl flashing to put behind the ledger, is that ok or should I have got the rubber stick on kind

  2. Expert Member
    MALCOLM TAYLOR | | #2

    Derek,

    The depth of your deck framing should be sized using span tables for the loading where you are. Depending on the loads, and where your beam is located, 2"x12"s may be unnecessarily large - which would solve your problem.

    Look at figure #15 in this link. It answers your question about attachment.
    https://www.nnva.gov/DocumentCenter/View/523/Residential-Wood-Deck-Construction-Guide-PDF

    1. DerekR | | #4

      I don’t want all this wood to be wasted that I bought I really just want to know if it can drop down 2 inches over the foundation and if the bottom bolts can be 4-5 inches above the bottom of the ledger

      Can I make the 2x12’s work if I need to

      1. Expert Member
        MALCOLM TAYLOR | | #11

        Derek,

        Figures #14 through #19 in the link I posted answer that question.

  3. plumb_bob | | #7

    I would say yes, but the devil is in the details. First, will you be working with a local inspector? Ask him/her first, the inspector may have some good advice on how to attach the ledger.
    Having the ledger hang down over the foundation may present the opportunity to fasten directly into concrete with wedge anchors, or to bolt an angle iron or similar to the foundation to help carry the ledger.
    Vinyl flashing will work if done correctly. Some people will space the ledger off of the house with washers or similar so any water can drain.
    Do a google search of "deck failure" and you will see that the ledger attachment is often the weak point.

    1. DerekR | | #9

      It won’t be able to attach to the foundation
      1: it’s only going to be covering the foundation by 1 inch
      2: the wall sticks out 1.5 inches past the foundation for future stoning on the foundation

      I remeasured though and my bottom bolts will be at 4 inches from the bottom of the ledger at most it’s possible for me to do 3.5 inches as well, not 5 inches, top bolts will be 2 inches from top and the ledger will drop 1 inch below the wall

      Deck will be 29 feet wide and come out 10 feet from the house

  4. walta100 | | #8

    If this deck needs to meet modern codes to pass inspection making the deck self supporting is generally the easy low cost option.

    Way too many stories about collapsed decks because someone though it was done right.

    Walta

  5. DerekR | | #10

    I have another question, since I didn’t need 2x12s but I got 2x12 ledgers can I attach 2x10s to the 2x12 ledger and use the 12’s for something else?

    1. Expert Member
      MALCOLM TAYLOR | | #12

      Derek,

      It would be a lot less complicated to rip down the 2"x12" ledger material to whatever depth you want.

      Another thing you might want to consider is setting your joist hangers so the top of the joists are 3/4" above ledger. This leaves a drainage space for debris and water between the ledger and deck boards above.

      1. DerekR | | #13

        Ok thanks, I can use 2x10s though on the 2x12 ledger if I wanted?

        That seems less complicated to me than trying to cut a 80 lb 2x12 down to 10 that’s 16 feet long with the limited equipment I have

        I’m going to put deck tape on top of the joists for water and debris

        Would you recommend vinyl flashing or the peel and stick flashing to go behind the ledger or are both fine

        1. Expert Member
          BILL WICHERS | | #14

          You can use one board as a guide to rip another board with a circular saw. It goes faster than you'd think, and just put your cut edge on the underside where any uneveness won't be a problem. If you have a number of boards to cut down, it's simple to make a basic jig (you'd want two of them, one for either end of the board), that will hold your guide board in position over the one you're cutting. That way you can just slap the boards together against the stop of the jig and not have to measure every time. This also ensures you cut all the boards to the same size.

          Bill

          1. DerekR | | #15

            Ok thanks but can I use the 2x10s if I wanted to, it would save me some money if I use the 2x12s for something else because the 2x10 are a good bit cheaper

        2. Expert Member
          MALCOLM TAYLOR | | #16

          Derek,

          If attaching the deeper ledger at the height you want is the problem, I'm not sure how using smaller joists helps?

          At the risk of being a bit blunt: There is nothing that says DIY more than seeing things like large ledgers and smaller joists because the builder lacked the skills to do basic carpentry tasks like ripping down stock. Ripping the 2"x12" can be done with a circular saw either free-hand following a chalk line, using the guide that came with the saw, or simply holding your other hand against the base-plate as a guide.

          Use peel + stick behind the ledger. You also need a cap flashing above. Put this on before you hang your joists so the return sits in between the ledger and end of the joists.

          The deck tape is a good idea, but doesn't deal with how water and debris escape from cap flashing over the ledger. That's why I recommended you set the joists up 3/4" to provide a drainage plane.

          1. DerekR | | #17

            I remeasured and the 2x12 ledger is only going to drop down 1 inch max so I’m ok with that now

            The reason is to save some money too if I use the 2x12s for something else, the 2x10s won’t even be seen because 2x12 will cover them on the outside perimeter, I was just wondering if it’s safe structurally

            I’m also building a deck at the side of the house later that I can use the 2x12s on that I already bought then I can buy some 2x10 to use on the front 2x12 ledger

  6. garyincentralflorida | | #18

    I have done this many times while I was up north. Was a very typical detail used for permitting. We where able to use a ledger or joist hangers. Code determined. But can use 2x12 for ledger if you want or worried about splitting. Predrilled should not be a problem. Flashing is important.

    1. DerekR | | #20

      Yea that picture is exactly how mine would look, thanks that makes me feel a little better

      1. garyincentralflorida | | #23

        Other than the decking,. which I dont know what you planned on,

    2. Expert Member
      MALCOLM TAYLOR | | #34

      Gary,

      I'm not that familiar with US codes , but the detail throws up a few questions:

      - There is no lateral load resistance for the ledger shown.
      - Is there not a requirement in the IRC that sill plates have full bearing?
      - I'm pretty sure bearing the joists on a 2"x2" ledger is no longer allowed.

  7. garyincentralflorida | | #19

    We would allow an area for the snow to melt and not melt into the doorway. We never had an issue with 4" step or trip point. It was to allow o door to open and avoid water infiltration/ rot under doorways main reason.

    1. DerekR | | #22

      The only way I could have a 4 inch step is if I used 2x8s and I don’t think that’s enough for a deck this size, my step down will be 3/4 inch

      1. garyincentralflorida | | #25

        No, it would be 4" less the decking. so 3" or 2/ 1/2" inches.
        Dont rip anything. Making more work than needed. I promise it is a typical detail done over and over. Flashing is the important. I suggest peel and stick with alum flashing.

        1. DerekR | | #28

          And does that stick on flashing go behind my house wrap and then I pull the house wrap over on it or does it go on top of the wrap?

  8. graham78 | | #21

    -One downside to ripping your ledger down would be that you are exposing the untreated portion of the lumber.
    -Using a 2x12 ledger with 2x20 joist is safe structurally assuming your spans are good.
    -I like to put the top of the decking right underneath the door threshold.
    - a self supporting deck with an extra set of post and beams is going to cost you more in labor and materials. You are also putting footers into "disturbed" soil. I think a ledger system is a "better" approach.
    -Having your 2x12 ledger hang down over the foundation and keeping your ledger "bolts" above the concrete is fine. (2" MINIMUM bottom edge distance)
    -The most important place for tape is on top of built up beams

    1. DerekR | | #24

      You put the ledger 1 inch under the door and have top decking directly touching the bottom of the door with no space? I was going to have a gap of 3/4 between the decking and the bottom of the door

      Going by what I read since it’s a 2x12 ledger the bottom bolt can be has high as 3.75 inches from the bottom of the board and the top bolt 2 inches from the top with a gap of 7.5 inches between the bolts

      1. garyincentralflorida | | #26

        How do you seal it from leaking? You will be battling ice constantly if it is even to bottom of door. We would make a lot of money from rotten rim joists for this reason.

        1. DerekR | | #27

          I was going to have a gap 3/4 from the door, I was responding to the other person that said he has no gap

        2. graham78 | | #29

          -The only way to correctly waterproof the door sill to ledger flashing would be to remove the door and install a sill pan that overlaps the ledger flashing. This is usually not in the scope of work so peel & stick/ silicone/ liquid flashing is the best alternative.

          -Keeping your deck hight a step down from the door threshold is common for the water argument that you make. I look at it like this - -Your door is either waterproof or not. Snow storms are not limited to ~4". I like to walk out onto the deck without a step down (top of decking just underneath bottom of door threshold). You still have 1" + to "attempt" to waterproof the door sill to ledger flashing which is easily done prior to installing decking. As long as the decking is spaced of the sheathing under the door, I don't see how a larger hight from decking to door is safer in terms of water mitigation.

          -3 3/4" is minimum end distance for your ledger locks, make your bottom row of ledger locks 2" above the bottom of house rim joist

          -wood ledgers in lieu of hangers are not good outside-
          https://www.jlconline.com/deck-builder/ledger-strips-and-the-code_o

          -Yes, peel and stick behind house wrap and then alum/ galv/ vinyl on top of peel and stick over the ledger/ you need to isolate the treated ledger from metal flashing with peel and stick.

          1. DerekR | | #30

            A 3/4 inch drop down from the door won’t hurt though will it?

  9. DerekR | | #31

    I’m thinking about using 1/2 inch spax powerlags for the ledger that don’t require any pre drilling, what’s the opinion here on those

    1. Expert Member
      MALCOLM TAYLOR | | #33

      Derek,

      Two other code requirements to consider.

      - You need to provide lateral resistance for the deck ledger, not just deal with vertical loads (figure #22 in same link).
      - Tied to that is you can not use ledgers rather than joist-hangers for support on exterior decks. It would defeat the purpose of the lateral load resistance for the ledger.

  10. graham78 | | #32

    -Spax has good engineering/ tech documents for the deck ledger detail, so that should work well.
    -I like to predrill slightly larger than the lags/ it doesnt really take any longer as it is easier to drive lags with a predilled hole. Layout the ledger on some sawhorse/ locate holes/ predrill and load the screws.
    -I think the "no predrill" thing is a lame marketing technique. Wood is going to split if you dont predrill it.

    1. DerekR | | #35

      Should I get 1/2 inch or 5/16 spax

      1. graham78 | | #38

        I like the flat head ones as they don't interfere as much with the placement of hangers.

  11. DickRussell | | #36

    Isn't this a good application for Maine Deck Brackets? It would let you drop the deck ledger as needed, provide for better sealing of the house ledger against water intrusion, and provide a gap for blowing/flushing tree debris from the gap between the deck ledger and the house. I used those brackets on my house, 12 years ago, and I'm glad I did for all the above reasons.

  12. plumb_bob | | #37

    As for the bigger picture, I deal with this all the time. Many people think its "just a deck" and miss critical elements such as ledger attachment, built-up beam construction (joints in the wrong location), lateral bracing, undersized columns (4x4 does not cut it) etc. Another thing people often miss is the fact that there may be an existing window below the level of the deck, and there is no thought to if there is a lintel or not. Decks also can take snow load so the design must take this into account.
    There have been several deck failures in the news lately, these things happen.

  13. Expert Member
    NICK KEENAN | | #39

    Did you buy the wood at a big box store? You can return it if you did.

    This is not the kind of project you want to do on the back of an envelope. At 29x12 the deck is 348 square feet. We're required to build decks to hold 50 pounds per square foot, which would be 17,400 pounds. These are not the kinds of loads you can just get by noodling around.

    1. DerekR | | #41

      I bought it at a small local place and it was a lot of work to get it here

      I want the deck to cover almost the whole front of the house, it’s 32 feet wide I’ll make the deck 29-30 feet, I may just bring the deck out 10 feet from the house instead of 12 and it’s 4 feet high to the bottom of the door

      What more can I do than putting the bolts 16 inches apart on the ledger, put 5 posts 10 feet out from the house, then connecting it all together?

      1. Expert Member
        MALCOLM TAYLOR | | #42

        Derek,

        "What more can I do than putting the bolts 16 inches apart on the ledger, put 5 posts 10 feet out from the house, then connecting it all together?"

        Here is how it's typically done:

        - First determine the load (dead + live) per square foot for your location.
        - With that information you choose the appropriate joists and spacing for the span.
        - You can choose a variety of beams to use based on that loading and how many posts you want.
        - Depending on how many posts you end up with, you size the footing based on the load from the post above.
        - Based on the structure you have come up with and the code requirements, you select the appropriate structural hardware and fasteners.

        What DC was getting at is: it's a systematic process based on calculations, tables and codes. You just don't randomly choose the size or spacing of anything.

      2. Expert Member
        NICK KEENAN | | #43

        There's a lot more you can do.

        Just to give a back-of-the-envelope look at what you're proposing, the ledger is holding half of the weight and the posts are holding half the weight. So that's roughly 9,000 pounds on the ledger and 9,000 on the posts, or 1800 pounds per post. Around here we're allowed to assume the soil can hold 1500 pounds per square foot, so each post has to have a concrete footer of 1.2 square feet, which is roughly a 14 inch square or circle.

        A ledger that can hold 9,000 pounds is no trivial matter. Even if it's mounted securely to the rim joist you have to worry about it pulling the rim joist off the house. And you have to worry about the deck joists pulling away from the ledger board. You also have to worry about loads that aren't just straight down buy exert twisting or racking forces.

        The point is, designing a deck is serious business. But here's the thing: it doesn't really cost more or take longer to do it right. While you're probably eager to get started banging on wood, take some time and do a little more planning.

        There's two ways to approach this. The first is to hire an engineer to design the deck for you. The second is to find existing plans and use them. Often local governments will have guides on the web for building decks, if yours doesn't I recommend something like this:
        https://www.portsmouthva.gov/DocumentCenter/View/92/Building-A-Deck-To-The-Code-PDF

        1. DerekR | | #44

          If it was the same thing here as what it is where your at that means the deck couldn’t be 30 feet wide unless I go through a lot more work, I may have to cut it down to 20 feet

        2. DerekR | | #45

          Let’s just say my soil is 1,500 lb soil and I did the 30 foot wide deck and I used 6x6 posts

          How wide and deep would the post hole need to be and how thick would the concrete at the bottom of the hole need to be how do I figure that

          1. Expert Member
            NICK KEENAN | | #57

            Does it get below freezing where you live? If it does the footings have to be below the soil that freezes, otherwise they will move when the soil freezes and thaws. Your local building department will publish a "frost depth." They will probably also publish a minimum soil bearing capacity, don't just use 1,500 lbs because that's what I use.

            Eight inches is a good thickness for footers.

  14. DerekR | | #40

    What’s a good brand of peel and stick membrane to put behind the ledger?

    I saw grace that has 18 inch wide and 75 feet long are there any others?

  15. hockipuck | | #46

    One more vote for freestanding has he mentions that the floor framing overhangs the foundation wall to allow for future lick and stick stone. This could mean the rim joist is unsupported and a deck ledger should not be attached.

    1. graham78 | | #47

      I agree with that statement. I must have missed the post saying that the floor framing is cantilevered over the foundation wall.

      1. DerekR | | #51

        My wall is 1.5 inches past the foundation but Still have the rim on the foundation they just added another board on the outside to bring it out, is that the same thing?

        There’s another board behind that board that’s resting on the foundation

        So I have a board on the foundation, another board attached to that board on the outside giving me a 1.5 inch overhang and then the osb on top of that outside board, so I would need 5.5 inch bolts to go through the ledger, osb and 2 other boards

        1. Expert Member
          MALCOLM TAYLOR | | #53

          Derek,

          I think you need more help with this that can be provided getting advice over the internet. You should approach either a designer or knowledgeable contractor. You simply don't have the knowledge or building skills to do this successfully on your own.

          1. DerekR | | #54

            Is that ok though? I still need information to give to people

            I also want to make sure I get someone that knows what he’s doing, he might say that’s ok when it isn’t

            Or he might say I can’t do that when it’s actually ok to do it

            So in your opinion is it ok to attach the ledger board to what I described? The 2 boards on the foundation and the osb over them. One board is on the foundation the other board is overhanging the foundation and they are attached together

          2. Expert Member
            MALCOLM TAYLOR | | #58

            Derek,

            No that's not adequate. As I wrote in post #33, you also require lateral resistance. All the code compliant details you need are in the link I provided in post #2 - that for some reason you are resisting looking at.

          3. DerekR | | #59

            I looked at it but I can’t find all the exact info I’m looking for, that’s why I was asking

          4. DerekR | | #60

            Thanks though, guess im going to move on to researching free standing decks and forget the attached deck

    2. DerekR | | #50

      Thanks I’ll look into that

  16. DerekR | | #48

    Ok this is what I’ve got so far

    My area also requires 50 psf for the deck
    I read ledgers hold 200 lbs per foot

    So I can make my deck a maximum of 30 feet wide and 8 feet out from the house for 240 sqft for a 12,000 lb load

    This give me 6,000 lbs at the ledger, 30 feet X 200 lbs a foot = 6,000 lbs right at the maximum of ledgers load and 6,000 lbs at the front of the deck on the posts

    Does this sound correct?

    Not sure what the weight load of the ground is here but it’s very hard ground to dig in, they had trouble burying my sceptic tank because of how hard the ground is so I know it’s atleast more than 1,500

  17. graham78 | | #49

    No.
    The the size of the deck is not limited by the ledger. The bigger the deck, the more ledger bolts are required. Read the chart is post #38 to determine how many bolts you will need.

    The span of your deck out from the house depends on the size of your deck joists.
    Look up DCA 6 for help on joist and beam spans.

    This is a great article to design your footings.
    https://www.finehomebuilding.com/project-guides/decks/sizing-deck-footings

    1. DerekR | | #52

      Ok so the joists can be 10 feet if the ledger bolts are spaced 20 inches apart, I was planning to space them 15-17 inches apart anyway

      I also asked this above:

      My wall is 1.5 inches past the foundation but Still have the rim on the foundation they just added another board on the outside to bring it out, is that the same thing?

      There’s another board behind that board that’s resting on the foundation

      So I have a board on the foundation, another board attached to that board on the outside giving me a 1.5 inch overhang and then the osb on top of that outside board, so I would need 5.5 inch bolts to go through the ledger, osb and 2 other boards. Is that ok?

      1. graham78 | | #55

        -Do you have a photo of the rim joist on top of the foundation?

        1. DerekR | | #56

          Not home right now I can tonight though

          Is that ok though to attach a ledger to what I described though

          I’m trying to get this figured out before the siding people are able to come in a month, I don’t want to delay them and tell them I’m not ready

          1. Expert Member
            NICK KEENAN | | #61

            We can't tell from here how your rim joist is attached. It doesn't matter how well the ledger is attached to the rim joist if the rim joist isn't well-attached to the house. Normally, the rim joist doesn't really carry any weight, its function is to keep the joists from falling over and give something to attach the bottom of the sheathing too.

            Check out this article: https://www.jlconline.com/deck-builder/deck-ledgers-and-i-joist-floor-systems_o

            In particular, look at this picture:
            https://cdnassets.hw.net/48/6b/ec576dc14c578df0587e67c2134b/structure-ilo-hero.jpg

            Caption for the picture is: "When a deck is attached to a house with an I-joist floor system where the joists are parallel to the rim joist, blocking and fasteners must be added as shown before installing the lateral load anchors. A similar detail is available from WIJMA for when the I-joists are oriented perpendicular to the rim joist."

            I'm not saying you need that level of reinforcement, that's just an example of the kind of reinforcement that can sometimes be necessary.

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