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16' Garage Door Headers

Discussion in 'Residential Structural Codes' started by vegas paul, Dec 24, 2009.

  1. mtlogcabin

    mtlogcabin Sawhorse

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    Just got this back from the state licensing board for engineers in answer to my questions about "praticing" engineering . Seems we do not practice engineering in the course of our jobs

    Based on your position as a building official and the fact that you review plans for compliance with the International Residential Code(IRC), I do not believe you are engaged in the practice of engineering. As you state below, you evaluate plans for code compliance and if you find discrepancies you request re-submittal, you do not make recommendations or provide design advice.

    With regards to your other questions, as a building official reviewing plans you are free to comment on or question all matters code related.

    If you have any questions, please feel free to contact me.

    Thank you:

    Stephen White

    Staff for Board of Professional Engineers

    406-841-2368

    Example Non engineered Plans

    As a local building code jurisdiction we will use StruCalc to verify a header size if it is beyond the prescriptive Tables of the IRC. It StruCalc says it is inadequate we notify the contractor and wait for a re-submittal. We do not recommend or provide a correct size.

    Is staff “practicing” engineering without a license?

    What are we as non-engineers allowed to comment on or question with regards to non-engineered drawings during the course of our plan review?

    What are we as non-engineers allowed to comment on or question with regards to engineered drawings during the course of our plan review?

     
  2. Mark K

    Mark K Platinum Member

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    This is definately an issue where the interpretation varies from state to state. California has taken the position that some of the action that a plan checker performs can constitute the practice of engineering.

    Plan checkers can comment on any aspect of the code. This is seperate from the question of whether or not they are practicing engineering.

    There is a concern that without sufficient education and training that a plan checker may think that he knows more than he really does. While this concern also applies to registered engineers it is more likely to be a problem with some one without an engineering education. If the plan checker lacks an engineering education it will be more difficult to discuss the issues with the structural engineer and to resolve the problem.
     
  3. jar546

    jar546 *****istrator

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    Since plan checkers are not specifying fixes or designing, they are no where near in the danger zone of architects and engineers licensing laws. Come on guys, this is the biggest thread and most active on the board!
     
  4. DRP

    DRP Gold Member

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    For a solid sawn header, the WSDD manual, why would that be viewed any differently than an engineered manufacturers tables?
     
    #224 DRP, Oct 6, 2010
    Last edited by a moderator: Oct 6, 2010
  5. Robert Ellenberg

    Robert Ellenberg Sawhorse

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    "Maximum length for a "dimensional lumber" header for roof and ceiling only; would require 4-2X12s and be limited to a 14' 1" span (TABLE R502.5(1); which would require a 6" wide wall; provided the building width was not more than 20'."

    I know the tables don't address this, but if it were a gable wall, wouldn't the load be less than roof and ceiling and therefore be allowed a greater span? Is this addressed in either of the computer program checks referred to?
     
  6. GHRoberts

    GHRoberts Silver Member

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    "As a local building code jurisdiction we will use StruCalc to verify a header size if it is beyond the prescriptive Tables of the IRC."

    So you are making engineering decisions. 1) That you know the proper engineering calculations. 2) That StruCalc performs the proper engineering calculations.

    Does StruCalc treat the wall as a diaphragm? If not you will get a wrong answer. The difference between the right answer and a wrong answer is code compliant or non-code compliant.

    (The right answer gives you the actual deflection and stress. Most engineering gives the wrong answer in the wrong direction if to the question as the AHJ asks it, but gives the wrong answer in the correct direction to the question an engineer asks.)
     
  7. mtlogcabin

    mtlogcabin Sawhorse

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    Do the prescriptive tables in the code assume all walls are a diaphragm?
     
  8. Uncle Bob

    Uncle Bob Sawhorse

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    GH,

    I've seen a steel brick lintel bolted to a header. Would that provide the support needed, if bolted to double 2 X 12s that spanned 16' ?

    Uncle Bob
     
  9. GHRoberts

    GHRoberts Silver Member

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    I believe the prescriptive tables ignore the diaphragm effects (strength of the sheathing) except in shear walls. But there are a lot of issues like load sharing between members that depend on the sheathing properties but ignore them.

    The proper response to the header in question is to simply say it is not prescriptive. Using StruCalc as a basis for negative comments is improper engineering.
     
  10. GHRoberts

    GHRoberts Silver Member

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    Uncle Bob ---

    I don't know. I don't know the design loads. I don't have the construction details. I am sure that some size of steel lintel would work. Perhaps one for a 16' opening.
     
  11. ggmarch

    ggmarch Member

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    it comes down to whether the roof above is trussed or stick framed.....i'm amazed at this thread and mostly it's length. there is good information, but the idea of engineering is figuring out an answer by specifics, no wonder the thread is so long, there are no specifics. but from the original post, where is it in the code? i couldn't tell ya, but as an architect it sounds like there's no load on the wall. assuming trussed roof construction.....if this is so, the only real weight is from the truss down to the top of the door frame. a 7 foot door up to a 8'-6 or 9 foot ceiling would amass a load in the neighborhood of 3-4 lbs /sf...a 4in12 pitch over that 16' opening would be (guessing) 61 wopping square feet or a grand total of 195 lbs or 12.2 lbs/lin foot on the header(assuming roof load is taken by the truss). i weigh 195 lbs and wouldn't worry about standing on a 16 foot span of a 2x12. so two 2x12's with a 1/2" spacer to match the wall width absolutely doesn't scare me. even if we add in the roof overhang to this, it's adding an additional 58 lbs/lin foot. i'd have to look up the beam's carrying capacity to be sure...

    but then again, my house has a central beam spanning 18'6 (3@2x12s hemfir) supporting ground, floor second floor and roof deck-1/2stick framed roof. no spacers either. and in 22 years it's deflected 3/8" at the center and no cracked drywall anywhere. so as for a gabled endwall with no apparent weight on it, i'd say a double 2x12 sounds good......but in the code, i can't support it from here and understand the trouble with finding it.

    adding brick that's another animal, but brick isn't all that heavy +/- 29 lbs/sf additional. as for the steel lintel, luckily they don't hold up the brick except during construction so that weight is just part of the beam anyhow....but it could be possible, once again, i don't know the factors involved to say one way or the other.

    fyi, architects can do engineering, however, it typically is only when it's a small part of the overall project and within our abilities. an example being, if i was asked to design a toll booth office building for a new toll bridge project, i would not be allowed to design the bridge too. but i could design the structure of the building, i could design the mechanical system and the lighting. likewise an engineer, who's asked to design a toll bridge complex would be allowed to design and stamp an architectural element like a toll bridge office building. i do my own engineering where i'm able and it has worked perfectly fine for many years. but i've noticed lately, code/building officials and township engineers(usually young kids out of college) have been asking specifically for an engineer's calculations, and many don't understand i am perfectly able to perform these tasks legally. i am not against people asking for more information and i give it, but there are times when i just shake my head and realize the person who's asking for it doesn't understand what's in front of them and i wonder how more information and calculation is going to make them understand it any better. but it does make sense to me and if they truly want to know how things are done, i'm willing to educate. but (to them, not you guys) please refrain from asking for an engineer when none is legally required.
     
  12. jar546

    jar546 *****istrator

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    Resurrected! This is the most active thread for a single subject that has more views per post than any other. This does not take away from An average Day and An Average Day too which is by far the largest of any thread.

    It must be good information if it is still getting tons of view, over 20,000 of them.
     
  13. fatboy

    fatboy Administrator

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    And yes, 27K+ views is over the top, crazy where this forum has gone............
     
  14. RJJ

    RJJ Platinum Member

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    And the original Poster is no longer with us!
     
  15. steveray

    steveray Sawhorse

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    Impressive amount of views for something that doesn't have video of somone getting bashed in a sensitive area....
     
  16. fatboy

    fatboy Administrator

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    And George Roberts......
     
  17. north star

    north star Sawhorse

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    ~ ( ) ~ ( ) ~



    ...and **Papio**, ...and **Uncle Bob**, ...and **gbhammer**, ...and

    **dcspector**, ...and **raider1**, and others who were helpful,

    ...insightful and had some common sense.

    BTW, ...anyone heard from **peach** & **Daddy-O** lately ? :?:

    ~ ( ) ~ ( ) ~
     
  18. fatboy

    fatboy Administrator

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    daddy-o posted this past weekend, and peach in the last couple weeks. UB is still out there also, just hit and miss.
     
  19. jar546

    jar546 *****istrator

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    I moved the post about the header for the steel building to its own thread.

    I love how active this thread is with solid content.
     
  20. fatboy

    fatboy Administrator

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    I am thinking you meant that in a positive tone, because this one is way OT at this point, good thing you split the new topic off.
     

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