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Thread: lvls loading

  1. #1
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    Default lvls loading

    Howdy, making a header out of 3 lvls 1 7/8' by 18" by 15' am wondering what the loading is in pound per lnft? Is it 3 times what one 17/8" 18" by 15' one is?

    Here is another question an 11 foot span made up of 3 2by10" supporting a plaster ceiling, second story outside floor, another plaster ceiling ,attic,and hip roof ridge is 23' above the attic floor. The room is 15' wide total width of dwg is 30'. This under engineered beam has held up for 105 years. So to beef it up i installed a 2 by 6 plate then 3 glued and nailed 1 7/8" by 11 7/8''lvls directly below the old beam. But am wondering does putting one beam under the other double the loading ability of the new mega beam? I have it figured to be bearing including snow load 2930 psfx per LnFt .
    Last edited by Timothy Miller; 02-24-2010 at 06:52 PM. Reason: typo

  2. #2
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    Default Re: lvls loading

    You lost me after "howdy"!

    I would say that the lvl manufacturer would be able to tell you how laminating multiple beams will affect their load rating and efficiency.

    I would question (out of curiosity ) why you would double up the original beam with a laminated lvl beam rather than replacing the original with the correct size engineered beam or steel. You know how it is, inquiring minds ...
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  3. #3
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    Default Re: lvls loading

    It's my understanding that the load rating of a given girder at a given span is cumulative when doubling, tripling, etc. So yes 3x the beam = 3x the strength. Unless you have compromised the original header in some way, you are supplementing it, and it still is contributing whatever resistance to gravity that it was last month.
    S_M
    Remove not the ancient landmark, which your fathers have set.

  4. #4
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    Default Re: lvls loading

    Timothy--- how did you come up with the need and design of that beam?
    For all you know all you needed to do was add another 2x10 or two --- or a steel fletch plate on each side.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  5. #5
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    Default Re: lvls loading

    Howdy, fellers the original beam was an opening from the dinning room to a bay window out crop. In renovating I extended the bay window out another 8'. The ceiling is 10' so i had the space to add a header below the original so i installed one. The construction is balloon frame. Another issue was the 20' by 8' sleepers porch added on top of the bay incorrectly 50 years ago. So when tearing open the ceiling below the Sleep porch i was amazed because nothing was done to beef up on the old bay window out crop roof. The porch should of collapsed years ago. Not much was holding it up. The second beam 3 lvls was installed to support, for the first time, the outside edge of the 20' long sleeping porch and the new 4' outcrop bay window roof beyond it. It was quite a feat to lift the 16' 18" deep lvls up onto the wall framing by my self thank goodness for my drywall hoist...

    I am confused about the nailing patterns on lvls that have joists supported by joist hangers. I read to install 4 rows of #10 nails 2" apart from the joist hanger on each side of the lvl beam. Is this in addition to the nails that made the beam up?

  6. #6
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    Default Re: lvls loading

    Oopsee, forgot to mention why i am making another beam up. Found a huge mistake in the ceiling of the master bedroom. In 1950 a plumber installing a toilet in the room above the master bedroom cut threw 3- 2 by10s. Notching this beam to run a waste pipe threw. The notch that is 8" by 7". So ever since the notched beam 15' span. has in the middle of it this notch- 2" deep 7" of the beam is holding up the plaster ceiling; the attic; the gable wall; and the roof. Plus the one story roof that adjoins the the gable wall noted above. The saving grace was that the ceiling joist run parallel to the beam. How on earth did the plumber not meet Jesus when he cut out the notch? Again the walls are 10' so adding a beam below will work in making a 2' wide bulk head around the entire room ceiling making it a custom ceiling.

  7. #7
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    Default Re: lvls loading

    I originally understood that your triple LVL was going underneath the original header, but now I'm not sure. The nailing pattern should be what you made up the triple with, not another round of nails, but add as many as you need to get to the specs. We use Timberlock screws before nailing to draw the individual LVL's tight together, esp. with a deep deep beam like yours there's no clamps with deep enough throats to do that. And just nails alone can't seem to draw them together very well.
    If your new triple is going on the side of the old header (as opposed to under it), you need to get engineering on fastening the whole stack together; I think that they would need to be well tied through with bolts , a lot of bolts.
    Plumbers do the damnedest things, don't they? Not to let the HVAC guys off the hook, either.
    Remove not the ancient landmark, which your fathers have set.

  8. #8
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    Default Re: lvls loading

    Howdy Sombreuil_mongrel, Thanks for you insight about beams. The new on is going under the old one in the master bedroom just like the other new one went under the old one on the outside wall that use to be in the dinning room. I forgot to mention on all the beams i used a whole bunch of pl premium too and bolts too as i'm into over kill when it comes doubts. Reading more about beams am amazed me how many fasteners to use when laterial loading with joists. Now i need to learn how many pounds of dead load a 2by6 joist/drywall ceiling is to be sure i use the correct # or fasteners on both sides of each joist hanger. Sure is great to learn more about building.
    Plumbers everywhere should have to learn about the forces on beams as part of their training. Wait till i rule the world then things will be different haha.

  9. #9
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    Default Re: lvls loading

    Howdy Went and explored the differences between Trusslock lag bolts and GRK RSS 5/16 by 5 1/8" hardened screws. The price for 50 is about the same but GRKs web page information and video won me over.Sombreuil_mongrel have you ever used the RSS hardened screws in assembling LVL beams?

  10. #10
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    Default Re: lvls loading

    No,
    but they look like really great screws.
    S_M
    Remove not the ancient landmark, which your fathers have set.

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