Results 1 to 17 of 17

Thread: Beam sizing

  1. #1
    Robert A. Kuzmick's Avatar
    Robert A. Kuzmick Guest

    Default Beam sizing

    I have a question regarding this beam. It is 9 ft long adequately supported on both ends through to the foundation and to the ground. It is actually 2 beams.... seperated by a 2 inch space for water lines. So, it is two 2x10x9ft nailed together, then a 2in gap and then another two 2x10x9ft nailed together. As you can see it supports 2x8 ceiling joists and rafters and some purlins. The snow load is 60 and the dead load is minimal ( insulation/sheetrock)1 story. I'm not not sure how to calculate for structural integrity, and was curious about whether this beam or beams is adequate, any info is appreciated, thanks.

    Similar Threads:
    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    Elite MGA Home Inspector E&O Insurance

  2. #2
    Join Date
    Mar 2007
    Location
    Healdsburg, CA
    Posts
    1,741

    Default Re: Beam sizing

    Some assumptions:
    1. Your a home inspector.
    2. Your not a PE.
    Unless you have PE after your name AND you where retained to determine the load bearing on any of the building’s support framing systems, oh why would you go there?
    If the local chapter of the International Structural Engineers doesn't have you up on charges for performing engineering without a required state license (assuming your state has such a civil code) then Mr. Peck and I will be happy to appear as your expert witnesses for the attorney you have retained to defend yourself and advise for a quick offer of settlement. I am not joking! Please take this advice to heart.

    Jerry McCarthy
    Building Code/ Construction Consultant

  3. #3
    Join Date
    Mar 2007
    Location
    York SC Licensed in NC and SC
    Posts
    596

    Default Re: Beam sizing

    You also have to figure in the span of the ceiling joists.
    It would be better if the members were southern yellow pine (SYP) instead of SPF. The gap you mentioned probably makes it overly complex to calculate and technically could be very close or over the span limit.


  4. #4
    Join Date
    Mar 2007
    Location
    Colorado Springs, CO
    Posts
    1,217

    Default Re: Beam sizing

    If the beam had obvious excessive deflection or movement you would report what you saw but, like the others said, your job is NOT to determine the structural capacity of the beam.

    Quote Originally Posted by Robert A. Kuzmick View Post
    It is 9 ft long adequately supported on both ends through to the foundation and to the ground.
    I beg to differ. All I see in your pic is a 2X? supporting one end of the beam(s). I can't tell if the 2X? is nailed or bolted to the wall or not but if it is not nailed or bolted to the wall then it is suspect. I would recommend the entire arrangement be reviewed by a SE.

    Also, that electrical panel beside the beam(s) support needs a cover.

    "Baseball is like church. Many attend but few understand." Leo Durocher
    Bruce Breedlove
    www.avaloninspection.com

  5. #5
    Join Date
    Mar 2007
    Location
    Lake Barrington, IL
    Posts
    1,363

    Default Re: Beam sizing

    Bruce B.:

    Robert was apparently there. He saw the supports and says they're ok. You only see the picture and have no idea what the support is beyond what Robert says. How can you flat out say it needs an engineer's evaluation? Engineers aren't cheap and recommending one should be done with due consideration, regardless of who pays for it.

    Eric Barker, ACI
    Lake Barrington, IL

  6. #6
    Jon Randolph's Avatar
    Jon Randolph Guest

    Default Re: Beam sizing

    Quote Originally Posted by Bruce Breedlove View Post
    I beg to differ. All I see in your pic is a 2X? supporting one end of the beam(s). I can't tell if the 2X? is nailed or bolted to the wall or not but if it is not nailed or bolted to the wall then it is suspect. I would recommend the entire arrangement be reviewed by a SE.
    Looks like more than one board turned sideways to me. There is romex routed through it. (don't forget that that wire needs nail protection)

    I would, however, have some concern with the modified trusses. I would recommend that an engineering certificate be provided to the buyer stating that all of the cutting and other modifications are ok.


  7. #7
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    25,314

    Default Re: Beam sizing

    Typical 'rule-of-thumb' for header/beam is 1 foot span for each inch high for 4x wide or doubled 2x with 1/2" plywood sandwiched between them, 4 foot minimum length, i.e., doubled 2x4 with 1/2" plywood sandwiched between them (may not even require the 1/2" plywood based on my memory, but to be safe, I'm including it) will span 4 feet.

    Likewise, a 2x6 = 6 feet; 2x8 = 8 feet; 2x10 = 10 feet.

    Now, though, that would typically be for SYP (southern yellow pine) and we are probably looking at SPF (spruce-pine-fire), so we need to compare the strengths of those two species of wood together.

    Southern pine and a Modulus of Elasticity of about 1,800,000 for #1 grade, SPF has a Modulus of Elasticity of about 1,500,000 for #1 grade - not a major difference. Not like Northern white cedar which has an E of about 800,000 for #1 or Ponderosa pine which has an E of about 1,200,000 for #1.

    Now, though, we are not talking about ONE doubled 2x10 beam, there are TWO doubled 2x10 beams there.

    So I doubt there will be much problem with the 'beam', now, though, 'bearing' comes into play.

    SYP has an Fb of about 1950 while SPF has an Fb of about 1400. That means that the fiber bending (crushing of the bottom of the end of the beam under load) of SPF is more likely to happen with the load as SYP would, however, separate that load to TWO beams and the load is reduced by half, so that may not be a problem.

    Typical bearing is usually at least 1-1/2", and a good rule-rule-thumb is bearing distance should equal beam width, so, a 4" wide beam should have 4" of bearing.

    The above, of course , is open to challenge and change by actual structural engineers who can do the calculations instead of using 'old carpenters rule-of-thumb'.

    Thus, in my NOT AN ENGINEER OF ANY TYPE opinion, that is probably okie dokie ... depending on the end bearing depth.

    Brandon, what say you?

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

  8. #8
    Brandon Chew's Avatar
    Brandon Chew Guest

    Default Re: Beam sizing

    BWA-HA-HA-HA.....

    West Coast Jerry is about to throw the poor guy in jail and East Coast Jerry is trying to egg me into practicing my profession outside the state(s) in which I am licensed ...

    Short answer: West Coast Jerry gave some good advice. Evaluating structural adequacy is a dangerous road to travel for a HI who is not a licensed design professional. As Bruce B. mentioned the HI should observe and report signs of non-performance, also having proper support of the beam is critical -- not only having enough bearing surface and a good load path down to the footings, but proper fastening of the jacks to the structure and proper blocking to keep the beams from rotating. Bruce K. is right that you need to factor in the width of the building (measured perpendicular to the ridge), the gap between the beams adds a wrinkle to the problem (which means you also need to look at how the parallel beams are fastened to each other, if at all), and my gut is agreeing with his statement that it "could be very close or over the span limit" -- even if all four 2x10s were built into a single girder*. Jon makes a good point about the trusses, if they were modified and not originally constructed that way.

    All of this is pointing to: The HI can advise the client if this has performed ok up to this point in time and under the conditions at the time of the inspection. If the client wants to know if this is going to perform ok in the future under design loading conditions, they need to have a qualified PE look at it.

    * Refer to 2006 IRC Tables 502.5(1) and 502.5(2).


  9. #9
    Aaron Miller's Avatar
    Aaron Miller Guest

    Default Re: Beam sizing

    Though the beam(s) in question may "seem" to be performing well, I have to side with West Coast Jerry. I'd draw the line at performing engineering analyses, especially on a roof with site-built trusses. Besides, I've filed so many complaints with the Texas Board of Professional Engineers against their members for malpractice, it would not be prudent for me to throw those kinds of stones.

    Aaron


  10. #10
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    25,314

    Default Re: Beam sizing

    I also side with the advice given by West Coast Jerry ... BUT ...

    You need to remember that this is the same building which Robert asked us about months ago where 'the previous owner' had cut the trusses out and he was wondering how to best address it.

    This is not an inspection Robert made, but a small house at his fishing/hunting/whatever camp.

    After my post, Robert PM'd me and HE DID have a PE out to look at the repairs to the trusses and those repairs were okay ... it's just that the PE did not make mention of that beam he was asking about.

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

  11. #11
    Robert A. Kuzmick's Avatar
    Robert A. Kuzmick Guest

    Default Re: Beam sizing

    Thanks for all the comments. I did have a PE give their stamp of approval on the modified trusses, but there is nothing in their report on the beam. Anyway, I guess the easiest solution would be to place a solid post underneath the beam at some point( maybe 16-18"' out), thus reducing the span and providing more support. Obviously, I would take the new post through to the foundation and ground.
    When I read the 2006 NYS ICC code, it states that a doubled 2x10 can handle ceiling and roof at 50 PSi live load, the span woudl be 7'8". My span is 9ft, but I have two doubled 2x10's 2inches apart.


  12. #12
    Robert A. Kuzmick's Avatar
    Robert A. Kuzmick Guest

    Default Re: Beam sizing

    BTW, the building is 25 ft across by 22 ft deep with a 60 Psi snow load with no attic above. Beam is 8 ft out from back wall.


  13. #13
    Join Date
    Mar 2007
    Location
    New Mexico
    Posts
    1,222

    Default Re: Beam sizing

    I figured it was your own house. That was why you asked, right? I'm not a PE either, but I would be surprised if that wasn't adequate. I used to do a lot of framing, and that was probably more than we would have done for a 9 foot span that was designed by our architects. You can probably get a PE to look at the calcs without too much trouble. If you are building the house yourself, the lumber yard may have someone from the mill that can help, or you can track one down on your own. It would be quicker than putting another post and footing into the building.

    Man, at 22 feet you almost could have done it without even needing the beam if you had the right configuration of TJI's at 12" centers. I think we did that once for at least 20 feet, and it worked really well.

    Jim Robinson
    New Mexico, USA

  14. #14
    Join Date
    Mar 2007
    Location
    New Mexico
    Posts
    1,222

    Default Re: Beam sizing

    My bad, I didn't look at the photo closely enough. This is the room with the vaulted ceiling, right? I remember this from a while back. The TJI's wouldn't work if you want to leave the interior open up to the peak. How is the project coming along?

    Jim Robinson
    New Mexico, USA

  15. #15
    Robert A. Kuzmick's Avatar
    Robert A. Kuzmick Guest

    Smile Re: Beam sizing

    Hey Jim, yes this is the room with the vaulted ceiling and that beam supports the ceiling joists and rafters. I'm not a carpenter but I did work for one for years growing up and learned quite a bit. Although, I never had to worry about loads, PSI, etc, etc, I just did what he said. Anyway, I'm just trying to rebuild this place as strong and secure as I can. It's my therapy I do tend to "overkill" things as you may have noticed from previous pics I posted in rebuilding the trusses and running new ceiling joists. The camp is coming along well, and I enjoy spending time up there. Just trying to take an old camp that was let go, along with cut trusses, etc and rebuild her for future generations. That's why I get a little worried about this beam, just want to make it safe for kids and family. Thanks for all the input!


  16. #16
    Join Date
    Mar 2007
    Location
    Cape Cod, Massachusetts
    Posts
    559

    Default Re: Beam sizing

    I see nothing but red flags with this modification.

    The trusses were modified. Any modifications to a truss requires an engineered solution, not a carpenter's experience thinking they are overbuilding for safety. (which they may not be doing)

    From the picture I can't see what is supporting the cathedral side of the roof rafters? Also how are the ceiling jopists in the kitchen being supported laterally?

    There are to many compound forces in effect with truss design to give any advice that the girt beam will hold up only the downward force of the roof load. A building permit would be required for this work and the local building opfficial wouldn't touch that one for all the tee in china. They would certainly insist on an engeineers stamped solution.

    My advise: Get an engineer to design the structure properly, get a late permit, and get the engineer to sign off on the work completed. It will ensure the safety of the structure and can accompany any future sale documentation. -- Besides, the future buyer's Home inspector will certainly pick up on it and it could delay or kill the deal.


  17. #17
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    25,314

    Default Re: Beam sizing

    Quote Originally Posted by Ken Amelin View Post
    I see nothing but red flags with this modification.

    The trusses were modified. Any modifications to a truss requires an engineered solution, not a carpenter's experience thinking they are overbuilding for safety. (which they may not be doing)

    My advise: Get an engineer to design the structure properly, get a late permit, and get the engineer to sign off on the work completed.
    Ummmm .... Ken ...

    Did you read the last few posts above?

    Robert DID get a structural engineer, and that PE ... DID ... sign off on the truss repairs.

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

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •