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  1. #1
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    Default deck beams and span charts

    Can anyone share any span charts for deck beam spans?

    I found a deck span over a double wide garage door. The span between the posts is 18'. Bearing on each post is a double 2x8. There is a 2x12 as a skirt and its nailed to the 2x8's but it is not bearing on posts. the deck is attached to the structure with a ledger that is nailed only and not bolted. It extends 4' out from the structure so it is more like a walkway then a deck. I'm pretty sure this span is two wide but I wanted some concurrence. Some pictures are below.

    There is other stuff wrong with the deck too but I wont bore you with that.

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  2. #2
    Gary Anglin's Avatar
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    Default Re: deck beams and span charts

    If you know how to use this (which I don't yet). It may be of some help to you.

    Maximum Span Calculator for Joists & Rafters


  3. #3
    Richard Moore's Avatar
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    Default Re: deck beams and span charts

    The above link only works for joists, not beams.

    A lot of the beam span tables simply max out at 12' (between posts).

    The longest span I can find is 15'8" for 3 southern pine 2x10s (nailed together I presume) on a deck 8' wide or less. (see http://www.opkansas.org/Documents_an...s/res_deck.pdf )

    I think you can count the nailed 2x12 as some extra strength, even if it is not supported, but that's still less than 3 2x10s and, of course, you are still well short of the 18'.

    Last edited by Richard Moore; 01-22-2009 at 09:57 PM.

  4. #4
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    Default Re: deck beams and span charts

    Looks like three 2x12's will work for 18ft beam span if local codes accept it since the joist span is only 4 ft.

    I see splices in those 2x8's that are not over a support.
    The connection to the house is the most dangerous item there.


    See pg 3
    http://www.knoxcounty.org/codes/pdfs/deck_handout.pdf


    http://www.fairfaxcounty.gov/dpwes/p...ks/details.pdf


    Deck Construction Information-PAHI


  5. #5
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    Default Re: deck beams and span charts

    I knew it wasn't right as soon as I saw it. Aside from the deck issues, check out the service drop. You can just about reach up and grab it.

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  6. #6
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    Default Re: deck beams and span charts

    BTW, I'm saving all the PDF's so thanks for posting them.


  7. #7
    Richard Moore's Avatar
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    Default Re: deck beams and span charts

    Better tables...thanks Bruce.

    Looks like 3 2x12s would give you up to 19' on a 4' wide deck in Knox county, but only 17'5" in Fairfax, as their width starts at 6'.


  8. #8
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    Default Re: deck beams and span charts

    Quote Originally Posted by Bruce King View Post
    Looks like three 2x12's will work for 18ft beam span if local codes accept it since the joist span is only 4 ft.

    I see splices in those 2x8's that are not over a support.
    The connection to the house is the most dangerous item there.


    See pg 3
    http://www.knoxcounty.org/codes/pdfs/deck_handout.pdf


    http://www.fairfaxcounty.gov/dpwes/p...ks/details.pdf


    Deck Construction Information-PAHI
    Bruce,

    I agree *sort of*.

    I clicked on the Fairfax County link and it shows 3 2x12 spanning up to 17'5" with a 0" - 6'0" span. The stated 4 foot joist span falls within that 3 2x12 beam span rating.

    The same 3 2x12 beam span is reduced to 15'-1" with joists spanning 6'-1" - 8'0", showing a 2' joist length increase with a 2'4" reduction in span, extrapolation would indicate that a 2' joist DEcrease would allow at least a 7" INcrease is span, but ... that table clearly shows the maximum span for a 3 2x12 beam with a joist span of 4 feet is only 17'5".

    That means that while 'the deck would likely be okay with' an 18 foot span, *I* would not make that decision because the table shows differently, and, being as *I* am not an engineer, *I* would not want to be held accountable for say that a 3 2x12 beam with an 18 foot span is "okay".

    HOWEVER ... the Knox County handout shows that 3 2x12 WILL span 18 feet, so ... your call, just don't let anyone know you 'found something which said differently if you are outside of Knox County'.

    Jerry Peck, Construction / Litigation Consultant
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  9. #9
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    Default Re: deck beams and span charts

    Here's a link to the American Wood Council's publication on "Prescriptive Residential Deck Construction Code". The ICC has put their blessing on it.

    http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf


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    Default Re: deck beams and span charts

    Quote Originally Posted by Wayne Carlisle View Post
    Here's a link to the American Wood Council's publication on "Prescriptive Residential Deck Construction Code". The ICC has put their blessing on it.

    http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf

    Which shows the same 17'5" span limitation for a 3 2x12 beam with a joist span of 6' or less.

    That same document was in one of the links above, but that is 'the best' document to go by.

    Which is why I said:

    HOWEVER ... the Knox County handout shows that 3 2x12 WILL span 18 feet, so ... your call, just don't let anyone know you 'found something which said differently if you are outside of Knox County'.


    Jerry Peck, Construction / Litigation Consultant
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  11. #11
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    Default Re: deck beams and span charts

    John, I don't know what it's like out by you guys but as a suggestion ...
    With the proliferation of decks, garage decks and all the related possibilities and the resulting collapses, many of the muni's around here have put together their own standards for decks.
    When I run into something like yours I go on the muni's website and often times there are deck / garage pdfs for download. I read it, comment about the condition and pdf in the report and provide the pdf as an attachment to the report. Clients love it, sellers (especially NC) hate it.
    For those muni's with no or minimal websites I call the building dept. Almost always they have something they can fax me. Which of course I fax to the client.
    Hope this helps.

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  12. #12
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    Default Re: deck beams and span charts

    Just don't use the IRC for spans on decks. You will have to use an alternative chart such as the DCA6 or the WFCM. Technically the IRC does not apply to decks because:

    1) Decks are post and beam construction which is not covered under the IRC.

    2) Decks are located outside and the span tables in the IRC are for dry applications and not exterior/wet applications.

    New decks under the IRC are required to be engineered unless your local jurisdiction has approved adopted design specifications.


  13. #13
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    Default Re: deck beams and span charts

    The above discussion is very useful, especially addending the local AHJ's deck construction details to the report.
    However, one item has been over looked in this discussion, that is; what is the species of the framing lumber? The span tables are based on the lumber species, which therefore governs the "strength" of the member in bending. Different species have different "strengths" and therefore can span different lengths. So any one who is attempting to use a span table for joists or rafters must know the species. Check the grade stamps on the lumber (if any?). Learn how to read grade stamps on lumber and plywood.
    Of course, if there are no visible grade stamps to the inspector, or if there is a mix of framing lumber species in the job, then the lowest possible value/span length for that size member should be used.
    Note that Southern Yellow Pine commonly used in deck contruction is not "as strong as" say Hem-Fir #2. Most lumber that is pressure treated has wideer rings and is softer that better grades of lumber to accept the chemical injection of the preservative.


  14. #14
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    Default Re: deck beams and span charts

    If we are adding items ... ... I seriously doubt that there are proper footings under those posts.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: deck beams and span charts

    The easiest part is the report.

    "The deck is built below standards and wrong. Have a qualified and competent contractor fix it.........Period."

    Done!

    ...but yeah, this discussion is good....


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    Default Re: deck beams and span charts

    sorry but it's not our place to command them to fix anything. Please say that you are joking and provide more info than that.

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    Default Re: deck beams and span charts

    What you guys are failing to see is that this is probably a lot stronger than what you might think!

    The trellis work acts as a truss and will span infinity!


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    Default Re: deck beams and span charts

    the western wood products association has a span table chart available on line. they list a 2x12 doug fir north select structural floor joist at 2' o.c. as being adequate for an 18' span for a 40# live load and a 10# dead load. they add value for repetitive use. the tributary load in the above case is 2' as in the charts for a floor joist at 2' o.c.. the house is supporting 2' of tributary load as well as the outside built up beam. a knee brace from post to 2x12 could reduce the span down to an acceptable distance. connections would also have to be addressed. i would require engineering but it looks do-able.


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    Default Re: deck beams and span charts

    Quote Originally Posted by Markus Keller View Post
    sorry but it's not our place to command them to fix anything. Please say that you are joking and provide more info than that.

    Markus,

    He is not "commanding" anyone to "fix it", he is simply stating what needs to be done, which is what we are getting paid for - "FIX IT".

    No joke about it, I sure hope you tell people to get things fixed ... or do you just say 'this is not right, but, hey, it's okay if you want to leave it'.

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  20. #20
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    Default Re: deck beams and span charts

    Some lags should be added... the span is most likely not correct.. but it won't be coming down for that reason... unless 50 500 pound people get on it. As to footers... not worth worrying about.
    aj

    So much non code work out there... but.. hey... we used to live just fine in caves.


  21. #21
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    Default Re: deck beams and span charts

    Quote Originally Posted by adkjac View Post
    but.. hey... we used to live just fine in caves.
    Then we discovered "fire".

    After that, we kept improving our dwellings.

    If you want to be a cave dweller, so be it. Your choice.

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  22. #22
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    Default Re: deck beams and span charts

    Jerry... put a lid on it dude. I have built more decks than you hava inspected... none moving an 1/8 of an inch. That walk way deck needs lags and that's it. You need a sock in your trap if you can't figure out how to be nice to me.
    love
    aj


  23. #23
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    Default Re: deck beams and span charts

    Quote Originally Posted by adkjac View Post
    Some lags should be added... the span is most likely not correct.. but it won't be coming down for that reason... unless 50 500 pound people get on it. As to footers... not worth worrying about.
    aj

    So much non code work out there... but.. hey... we used to live just fine in caves.

    Not so quick there, it very well could come down due to improper connection to the house.

    This has become even a larger danger if the new treated lumber is used with regular nails.


    Also, never just state something is substandard and recommend repair unless you are doing that for repeat agent referalls ( which should be a criminal offense). Here's why:

    The agents are telling your clients this "oh, he just said that to protect his self, it may not meet code completely but you see that he did not say what was wrong with it so it really does not have much wrong"

    Report what is wrong and the safety issue present or get out of this business please.


  24. #24
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    Default Re: deck beams and span charts

    Quote Originally Posted by adkjac View Post
    Some lags should be added... the span is most likely not correct.. but it won't be coming down for that reason... unless 50 500 pound people get on it. As to footers... not worth worrying about.
    aj

    So much non code work out there... but.. hey... we used to live just fine in caves.
    Quote Originally Posted by adkjac View Post
    if you can't figure out how to be nice to me.

    "be nice to" you? I am being nice to you.

    That's not a problem, only your posting that all those violations and poorly constructed elements of that deck are ... well .. "not worth worrying about".

    That may work for your uneducated clients, but not for an audience who knows better.

    Besides, you brought up "we used to live just fine in caves", no, we used to live in caves, yes, then we managed to figure out how to get out of those caves and live in something a tad more decent.

    However, if you feel "just fine in caves" ... your words, not mine ... then do so.

    Jerry Peck, Construction / Litigation Consultant
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  25. #25
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    Default Re: deck beams and span charts

    Read my posts goof balls... I said lags are needed. And that the span is wrong... however... if I were to work on it... I would only add the lags... as I feel the span will never let loose for being 18'. I do feel that the lags are mandatory!!!!!!!!!!!!!!!!!!!!!!!!!!!

    peace
    aj

    Why does it take multiple posts for even a close understanding of what is being said? Please do not respond... just talking to myself.


  26. #26
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    Default Re: deck beams and span charts

    Quote Originally Posted by adkjac View Post
    Why does it take multiple posts for even a close understanding of what is being said?
    Don't know, define your problem and maybe I can help.

    ... just talking to myself.
    Oh, now I see part of the problem.

    Jerry Peck, Construction / Litigation Consultant
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  27. #27
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    Default Re: deck beams and span charts

    Jerry... you are this boards insult dog.

    Have a bone you nut. good night
    aj


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    Default Re: deck beams and span charts

    I thought you were talking about adding lags to correct the spliced 2x8's and improperly attached rim board.

    So you were going to correct the house attachment with lags.

    Lags are usually not correct either, through bolting is usually required assuming something substantial is there to bolt to.


    Are you an inspector or "deck builder/repairman"?


  29. #29
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    Default Re: deck beams and span charts

    FIX IT, sounds like an order to me. Orders are meant to be followed. I do not consider myself powerful or audacious enough to give clients orders. They usually don't listen anyway, regardless of how it is put.
    FIX IT, is also presumptive. I would be telling them to fix something that they may not want to fix. The client may hate component X and want to remove it. It is not my place to tell people to fix things, just as it is not my place to tell someone whether they should or shouldn't buy a particular property.
    I tell clients essentially that if component X is to remain, then someone should ..., it is important that it is ..., it either is currently or will be D&H, etc.
    I tell my clients what the problem is clearly and understandably, what their options are and the best possible remedies. When I'm done my clients know what time it is.
    If the line John posted is all the info he wants to provide, then that's fine with me. Those types of explanations are indicative of the barely legible, handwritten comments I see on crappy checkbox reports. I'm not saying that's what HE does because I don't know.
    Quite honestly, as much as I hate those types of reports for our profession, I really like them personally.
    Probably 15-25% of my biz is doing re-inspections for people after they've already paid for a report that essentially tells them much of nothing.

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  30. #30
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    Default Re: deck beams and span charts

    I just report a wholesale statement to either repair or replace all items listed in the summary.

    I have also many times reported "Do not use the deck until proper repairs have been made"

    One time I reported "Do not visit the property until repairs to the front gutter have been made". This was a case where the gutter had about 75 lbs of debris stacked up and was hanging very loose right over the sidewalk leading to the only front entrance.


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    Default Re: deck beams and span charts

    Quote Originally Posted by Markus Keller View Post
    sorry but it's not our place to command them to fix anything. Please say that you are joking and provide more info than that.
    I'm not joking. Of course, what I said was not a direct quote from a report. My reports include specifics about what is wrong, how it will or can have a negative affect, who to call to get it fixed, but not much more. If we say more than we need to, we step out on a limb.

    K.I.S.S.

    1. Observe.
    2. Concern.
    3. Action.

    Like you do Markus, I too link PDF's with related info in the report comments.

    Last edited by John Dirks Jr; 01-24-2009 at 11:09 PM.

  32. #32
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    Default Re: deck beams and span charts

    Quote Originally Posted by adkjac View Post
    Jerry... you are this boards insult dog.

    Have a bone you nut. good night
    aj
    You get what you give out. Give out good advice and good posts and you will get the same back.

    Do the opposite as you have been doing and expect the opposite.

    After all, you are a good teacher, and I am a fast learner, I learn by watching you as to how you want to be treated.

    Jerry Peck, Construction / Litigation Consultant
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  33. #33
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    Default Re: deck beams and span charts

    Quote Originally Posted by Markus Keller View Post
    FIX IT, sounds like an order to me. Orders are meant to be followed. I do not consider myself powerful or audacious enough to give clients orders. They usually don't listen anyway, regardless of how it is put.
    This is how HIs typically state it:

    Quote Originally Posted by Bruce King View Post
    I just report a wholesale statement to either repair or replace all items listed in the summary.
    But all that is is just another way of saying "FIX IT".

    Jerry Peck, Construction / Litigation Consultant
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  34. #34
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    Default Re: deck beams and span charts

    Imagine a trial lawyer reading a comment from your report, only he's not trying to understand it, he's trying to misunderstand it. The more words you write the more there is to misunderstand.

    The more direct and shorter you can be the better. When you find something wrong you say what you see, say why its a problem and make a recommendation for correction.

    As far as making the recommendation for correction, I can't think of anything more direct and shorter than;

    Have a qualified "whoever" FIX IT.

    If it can't be misunderstood, its good information for your client.


  35. #35
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    Default Re: deck beams and span charts

    John,

    Maybe you could treat it like a prescription and list the side effects *if you do not FIX IT*, and, like prescriptions, list the more important ones first, and the most important one(s) in all caps, such as ...

    The deck is improperly constructed due to blah, blah, blah, I recommend you FIX IT, and, should you chose not to FIX IT here are side effects which could happen, this is not a complete list, but it includes:
    - YOUR SPOUSE COULD COLLECT ON YOUR LIFE INSURANCE POLICY (you could die).
    - YOU could be SERIOUSLY INJURED.
    - YOU could be INJURED.
    - You could face the COST of having to have it deconstructed and properly reconstructed during your ownership.
    - You could have to replace it when you become a seller.

    Jerry Peck, Construction / Litigation Consultant
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  36. #36
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    Default Re: deck beams and span charts

    OP Stated:
    "The deck is built below standards and wrong. Have a qualified and competent contractor fix it.........Period."

    This is a very poor, unprofessional statement to put in your report if this is the language that you used, would have used or will use. I would reword that statement to make a more professional and concise statement.

    1) Is built? Present tense? When was it built?
    2) “….built below standards….” What standards are you referring to? Is there an ordinance in the municipality that requires homes to be brought up to current standards upon real estate transfer?
    3) What is qualified and competent? Is there licensing in your area too? What type of contractor?
    4) …..”fix it.” Very unprofessional and vague. You are implying that it can be repaired. What if all contractors want to tear it down and build a new one?

    What I am getting at is the fact that we need to elevate the language in our reports. If you are going to cite standards which you did, you need to be more specific and make sure that they apply. There are other ways to get your point across without citing standards.


  37. #37
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    Default Re: deck beams and span charts

    Jeff,

    I did not use the comment in a report. It was an attempt to exaggerate how simple it was to cunclude the deck was messed up. It was meant for this forum only.

    How about this for a real report?

    The deck was poorly built. The beam span is too long by any listed standards. It is not properly attached to the structure and it could fall which would be a threat to the safety of persons. Have a qualified contractor fix it.

    Now let me ask you this. Would you rather have a contractor that you knew was qualified, or one that you knew was licensed?

    In my opinion, qualified includes licensed but licensed dosent always mean qualified.


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    Default Re: deck beams and span charts

    Also,

    Qualified has a meaning but it can vary depending on the situation. Am I as a home inspector charged with the responsibility of saying what qualified is for every given circumstance? I think qualified is a strong word that covers the bases and helps clients make good decisions.

    When I say fix it, I don't expect it to confuse a qualified contractor. If they determine it needs to be torn down and redone, thats their decision.


  39. #39
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    Default Re: deck beams and span charts

    John, I agree about the qualified vs licensed since not all licensees are qualified.

    How about :

    REPAIRS NEEDED:

    The deck does not appear to have been constructed using standard, established construction techniques and does not comply with past or current standards that were in place when the deck was constructed. There are serious safety concerns due to the overspanned end joist beam over the garage door along with...................................

    It is recommended that the deck be evaluated for repair or replacement and costs by a qualified/licensed contractor prior to closing.

    Not perfect but still gets the point across. Just know what standards were in place if you make that reference like I did.


  40. #40
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    Default Re: deck beams and span charts

    I don't worry about when codes/standards were established or if they even apply in a particular location. Of course the knowledge of such helps me make decisions based on common sense.

    No matter what, when, or where codes/standards were implemented, I always have my common sense. I'm not paid or qualified for that matter, to dictate law or jurisdictional rules to anyone.


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    Default Re: deck beams and span charts

    Quote Originally Posted by Jerry Peck View Post
    John,

    Maybe you could treat it like a prescription and list the side effects *if you do not FIX IT*, and, like prescriptions, list the more important ones first, and the most important one(s) in all caps, such as ...

    The deck is improperly constructed due to blah, blah, blah, I recommend you FIX IT, and, should you chose not to FIX IT here are side effects which could happen, this is not a complete list, but it includes:
    - YOUR SPOUSE COULD COLLECT ON YOUR LIFE INSURANCE POLICY (you could die).
    - YOU could be SERIOUSLY INJURED.
    - YOU could be INJURED.
    - You could face the COST of having to have it deconstructed and properly reconstructed during your ownership.
    - You could have to replace it when you become a seller.

    Thank you so much Jerry. Now I see the light. My reports will now be 100 pages long.


  42. #42
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    Default Re: deck beams and span charts

    that walkway is going nowhere. Codes or no codes. Yes... as an inspector mention lags/bolting, the span and location of splices... but... it is not a critical fault....

    Here's my inspector statement on a report....

    Deck walkway has what appears to be some code issues that are less than standards today. Recommend having it brought up to present code standards.

    Jerry... bark bark bark... I sleep soundly through all your nonsense.
    aj


  43. #43
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    Default Re: deck beams and span charts

    I think you are correct in noting that there may be problems with this deck, but I would respectfully suggest that you are stepping beyond the bounds of inspector into the realm of designer. I'm not sure why you'd want to take on the liability for that.

    You should note the problems and refer the home owner to a qualified architect or structural engineer (check with your local AHJ), rather than rely on span charts. I know that not every jurisdiction requires the use of an architet for residential design (which is probably how this mess became a reality), but in this case it certainly appears to be warranted.



    Quote Originally Posted by John Dirks Jr View Post
    Can anyone share any span charts for deck beam spans?

    I found a deck span over a double wide garage door. The span between the posts is 18'. Bearing on each post is a double 2x8. There is a 2x12 as a skirt and its nailed to the 2x8's but it is not bearing on posts. the deck is attached to the structure with a ledger that is nailed only and not bolted. It extends 4' out from the structure so it is more like a walkway then a deck. I'm pretty sure this span is two wide but I wanted some concurrence. Some pictures are below.

    There is other stuff wrong with the deck too but I wont bore you with that.



  44. #44
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    Default Re: deck beams and span charts

    Quote Originally Posted by David DelVecchio View Post
    I think you are correct in noting that there may be problems with this deck, but I would respectfully suggest that you are stepping beyond the bounds of inspector into the realm of designer. I'm not sure why you'd want to take on the liability for that.

    You should note the problems and refer the home owner to a qualified architect or structural engineer (check with your local AHJ), rather than rely on span charts. I know that not every jurisdiction requires the use of an architet for residential design (which is probably how this mess became a reality), but in this case it certainly appears to be warranted.
    Dave,
    In my opinion, he is not taking on the liablility or role of a design professional. I believe the reason for wanting to see the span chart is to verify that what he sees is a problem. This way he can confirm a defect so that he can report it.

    If he were to specify the repair then he would be taking on that role in which case he is going well beyond the scope of a home inspector.

    The utilization of prescriptive codes to make a decision of whether a situation is a defect or not does not constitute taking on the role of a designer.


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    Default Re: deck beams and span charts

    Deck beam spans for simple geometries are relatively easy to calculate for informational purposes (i.e. I am not an engineer and the following is not engineering advice).

    We'll assume a LL of 70psf (60 psf is a commonly accepted minimum) and a DL of 15psf. This gives us a total load of 85psf. Our span is 4' and our clear opening is 18' which give us a total load of 3060lbs for the tributary section in question (assuming proper ledger board sizing and attachment). Our beam total load then is 170plf and our live load is 140plf which, according to the SPIB, can be accommodated with (3) 2x12 #1 SYP members (3-2x10 members meet the TL requirement but not the LL requirement). Using #2 graded lumber we're still able to meet the requirements with a properly built-up beam constructed with (3) 2x12 SYP members. Minimum bearing is 1.5" which is not an issue in this case.

    For simple designs this type of calculation should give you confidence enough to say a particular structure is probably within guidelines or not. Anything more complicated and you should call in the architects or engineers.

    By the way, for the structure in question (2) 2x8 #2 SYP members (since grading was not specified I'm assuming common lumber that might be found at a big box store) can support 53plf TL and 39plf LL, less than a third of the design criteria above. Even allowing for the minimum of a 60psf LL you're still at only a third of the required beam strength. This is why decks fail and people die - because incompetent people build them incorrectly and people who should be competent say it's all good.


  46. #46
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    Default Re: deck beams and span charts

    Quote Originally Posted by Jeff Remas View Post
    Dave,
    In my opinion, he is not taking on the liablility or role of a design professional. I believe the reason for wanting to see the span chart is to verify that what he sees is a problem. This way he can confirm a defect so that he can report it.

    If he were to specify the repair then he would be taking on that role in which case he is going well beyond the scope of a home inspector.

    The utilization of prescriptive codes to make a decision of whether a situation is a defect or not does not constitute taking on the role of a designer.
    You are 100% correct.
    At a recent NJDCA seminar called 'Decks: Plan Review and Problems'; the instructor (Jack A. Boekhout, if you every see a seminar given by him, pay double to attend) went step by step on what a code official should do during plan review.
    He handed out 'quick charts' to be used by the plan reviewer to ensure the deck designer knew what he was doing.
    I carry these charts in my truck and use them often while on site (after the inspection) if I think there's a problem.

    John, send me your fax number and I'll fax you these charts.

    Darren www.aboutthehouseinspections.com
    'Whizzing & pasting & pooting through the day (Ronnie helping Kenny helping burn his poots away!) (FZ)

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    Default Re: deck beams and span charts

    Thanks Darren. My fax number is 1-800-679-4212




  48. #48
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    Default Re: deck beams and span charts

    Quote Originally Posted by Jeff Remas View Post
    Just don't use the IRC for spans on decks. You will have to use an alternative chart such as the DCA6 or the WFCM. Technically the IRC does not apply to decks because:

    1) Decks are post and beam construction which is not covered under the IRC.

    2) Decks are located outside and the span tables in the IRC are for dry applications and not exterior/wet applications.

    New decks under the IRC are required to be engineered unless your local jurisdiction has approved adopted design specifications.
    Jeff;

    I'm not following your thinking here.

    According to the NJ 2006 IRC table R301.5 gives you a load requirement 40 lb live load.

    R319.1.3 Geographical areas states 'members exposed to weather'

    and of course R502.2.2

    So, using all these sections, why is the IBC needed?

    Darren www.aboutthehouseinspections.com
    'Whizzing & pasting & pooting through the day (Ronnie helping Kenny helping burn his poots away!) (FZ)

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    Default Re: deck beams and span charts

    What Jeff was referencing in the IRC, I believe, is that Tables R502.5(1) does not address spans for decks.

    That table only addresses girders (beams) and headers supporting:
    - roof and ceiling
    - roof, ceiling and one center-bearing floor
    - roof, ceiling and one clear span floor
    - roof, ceiling and two center-bearing floors
    - roof, ceiling and two clear span floors

    And that Figure R502.2 only addresses "Floor Construction".

    Also, Tables R502.3.3(1) and (2) only address cantilever joists for (1) supporting exterior wall and roof only, and, (2) supporting exterior balcony, respectively.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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    Default Re: deck beams and span charts

    Quote Originally Posted by Darren Miller View Post
    He handed out 'quick charts' to be used by the plan reviewer to ensure the deck designer knew what he was doing.
    I carry these charts in my truck and use them often while on site (after the inspection) if I think there's a problem.

    John, send me your fax number and I'll fax you these charts.
    Darren,

    How many pages? Can you scan that in and post it here?

    Thanks,

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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    Default Re: deck beams and span charts

    Although this thread is very informative, it is dangerous to advise a client on design engineering if you are not licensed to do so.

    Instead of taking an engineering stance on the deck structure and exposing yourselves to liability and potential disciplinary action from your state licensing board, I suggest to stay within the role of the home inspector and simply advise your clients:

    "Additions to the house have modified the original structure. A building permit and approvals by local authorities is required for work of this type."

    "You should ask the owner if a building permit was issued for the work and to provide you with a certificate of approval or you may check with the town hall for your record and safety".


  52. #52
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    Default Re: deck beams and span charts

    Darren,

    Jerry's post #49 correctly addresses your question to me.

    The span charts inside the IRC do not apply to decks, those charts are for dry application. There is a difference in span limitations between wet and dry applications.

    The IRC does not apply to post and beam construction.

    Decks must be engineered since there is no prescriptive code for them. Those charts in the IRC will "ball park" you only but still do not apply.

    My information comes from my participation in a 12 person round table meeting put together by the PHRC in our state that included some real heavy hitters in the industry. There were representatives from state government, code officials, code educators, builders, architects, engineers and myself as a private inspector.

    As a result of this meeting and then the work of the PHRC, a deck program was put together for educating inspectors and contractors.


    The IRC applies to decks: (not all inclusive)

    With a height => 30"
    Stairs & Landings
    Handrails & guards
    Stairway illumination
    Tempered glass
    Live Load
    Dead Load
    Cantilevered portion of a deck where used must meet the balcony live load
    Corrosion resistance
    Protection against decay
    Most but not all connection types
    Flashing
    Footer/Frost depth
    Notching and drilling


    Other references needed for exterior deck applications:

    AFPA, DCA6
    Wood Decks, Forest Products Society (post sizing and other issues)
    IRC 2007 supplement (not adopted in all states including mine)
    Span Tables from:
    * AFPA Span Tables
    * Southern Pine Council
    Wood Truss Counci for attachment of residential decks to wood truss floor systems.


    Tributary loading of the beam and footings must be calculated and sized accordingly.

    Attachment to cantilevered portions of the house are not allowed.
    Attachment to brick veneer not allowed (hollow space behind brick is issue)

    You can spend 8 hours just learning some of the stuff.

    My mentor: Profile


  53. #53
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    Default Re: deck beams and span charts

    While we're on the topic of decks and their construction, here's a nice informative document. It was to big to post below so I hosted it at my server. You can open it and save a copy if you want.

    http://home.comcast.net/~arundelhome...-fasteners.pdf


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    Default Re: deck beams and span charts

    If you go to Southern Pine Council™ | 1-504-443-4464 | decking, docks, marinas, bridges, roofing, windows, lumber, treated wood and gardens and look under publications they have all the span charts you would want including a section for wet service lumber


  55. #55
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    Default Re: deck beams and span charts

    Paul,

    Good link for those span charts.

    Thanks,

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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