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Thread: Cantilevered beam calculation below standard residential load

  1. #1
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    Cantilevered beam calculation below standard residential load

    I want to reinforce existing 2x10 joists with 3 laminated 2x6s. The support will begin in a crawl space and extend through a wall in to the finished space. I do not want a support in the finished space. My question is how far I can extend the laminated 2x6s into the finished space. I am attaching a sketch which I hope will make this much clearer. Thanks. Sketch for cantilevered reinforcement.pdf

  2. #2
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    Anywhere from 2' to 20' depending on load.

    By the way, how long is this piece of string?

  3. #3
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    smegal:

    Does the CMU wall, which parallels the proposed laminated beam, continue into the finished area?

    dale

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    Dale, the CMU wall parallels the 2x6 he is asking about. See the question mark dimension in the top right of the sketch.

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    Oh, my mistake.
    I thougth the question mark was referring to the length of the cantilevered portion of the beam.
    Since the CMU wall parallels the beam into the finished area,
    I have to ask why there is reinforcement of the 2x10's only 3 feet away from the CMU wall?

    Is the CMU wall failing?
    What is he doing, putting a Hot Tub up there?

  6. #6
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    Quote Originally Posted by dalecyr View Post
    I thougth the question mark was referring to the length of the cantilevered portion of the beam.
    It is, and the top view shows the 2x6 extending into the "finished area"
    The view below shows the 2x6 parallel with the CMU wall.

    Quote Originally Posted by dalecyr View Post
    Is the CMU wall failing?
    What is he doing, putting a Hot Tub up there?
    There could be a dozen reasons. Maybe it is an old house and the 2x10 were spaced too far apart and the floor has sagged. Maybe the "finished area" is a basement garage as she/he shows crawl space on the left and 6' or 7' on the right.

    Not up to us to know why, just help with the questions. However since she/he has not provided a load it is impossible to answer the question.

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    Thanks to all. The load above this area even tho 3 feet away is excessive with ceramic tile and washer/dryer and also contains stove and refrigerator. which cause vibrations. The CMU wall is not failing. I asked for the length beyond the last post in the crawl space which would be acceptable given the support of the 3 laminated 2x6 and the spacing of the 2 jack posts in the crawl space. I appreciate the help.

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    Same answer, ANY cantilevering will be dependent on load on the cantilever.

    Where is that piece of string?

  9. #9
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    "I asked for the length beyond the last post in the crawl space which would be acceptable given the support of the 3 laminated 2x6 and the spacing of the 2 jack posts in the crawl space. "

    Just curious.
    Are you looking to us to do all of the work to figure this out for you, and give you an answer in feet?
    Or are you asking which formula on this site you need to use, or perhaps the meaning a one of the variables of the formula?

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    Last edited by Kelly_Bramble; 10-13-2011 at 07:26 AM.

  11. #11
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    Quote Originally Posted by dalecyr View Post
    "I asked for the length beyond the last post in the crawl space which would be acceptable given the support of the 3 laminated 2x6 and the spacing of the 2 jack posts in the crawl space. "

    Just curious.
    Are you looking to us to do all of the work to figure this out for you, and give you an answer in feet?
    Or are you asking which formula on this site you need to use, or perhaps the meaning a one of the variables of the formula?
    I am not an engineer. I could do the equations but I do not have the many tables available that you have that give specifications such as the modulus of elasticity and others. I did look at the page that Kelly suggested but could not determine what equation to use. I did not see in the first link any indication of a cantilevered extension. Thanks

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