Engineers, Architects, and other really smart people....

RobMcBee

RobMcBee

Slow n easy when you're not gettin greasy....
Joined
Jan 12, 2009
Location
Fort Mill / Indian Land SC
..... what is the maximum span of a double 2x12 LVL?


My shop is a 24x30 with a double 2x12 LVL running the 24' span. When we bought the place someone had crudely sistered a couple of 2x6s and put them in the middle as a support. I removed them and put in a solid pole. I'd like to remove it also and have an open floor for my woodshop. Is this possible?
 
Before the smart guys answer....a few questions: What is the load/use of loft (storage, office, living)? How much deflection/bounce is acceptable? I assume the LVL is supporting ends of joists? What is their span?
 
Need to know what the LVLs are supporting.

And if it's a 11-1/4" or 11-7/8" deep.
 
kaiser715 said:
Before the smart guys answer....a few questions: What is the load/use of loft (storage, office, living)? How much deflection/bounce is acceptable? I assume the LVL is supporting ends of joists? What is their span?
Click to expand...

Above is a guest room and storage, the shop is separate from our house (stand alone).

I don't mind a little deflection, the room rarely gets used.

Yes it's supporting the joist, they are 2x10's and span 15'

shawn said:
Need to know what the LVLs are supporting.

And if it's a 11-1/4" or 11-7/8" deep.
Click to expand...

They are supporting the floor joists for the upstairs room. The LVL is 11-7/8"

Fabrik8 said:
I'm assuming that the LVL isn't there to prevent the walls from ballooning?
Click to expand...

I don't think so, pretty sure it's just to support the joist.


Also the lower walls are studded 12" oc and the uppers are 16" oc. I'm guessing they did this for weight support. There are no dividing or load bearing walls above, it's just one large room (24x30). Here's a few pics of the beams...

Best pic of exposed Beam
IMG_1839.JPG


Wiring is temporary.... lol
IMG_1840.JPG
IMG_1841.JPG

My repurposed stripper pole.... (not joking)
IMG_1842.JPG
IMG_1843.JPG
 
For those not smart like me LVL=laminated veneer lumber. Basically a 2x12x30(in this case) piece of plywood. Very strong.

From the looks of the pictures the pole is the least of your worries for space. :flipoff2:
 
It's a ummmm..... work in progress..... yeah that's it.....


That's the side that accumulates all the.. stuff. Other half is clean
 
Ah, OK. So there's a floor above that. I couldn't get a mental picture of what was going on.

So even if a doubled 12" LVL isn't strong enough, you could remove it and substitute with something stronger/deeper. It would stick down below the joist level, like the sistered 2x6 already does. The joists are already joined at that point, etc., so you'd just be replacing like-for-like as far as joining to the joists are concerned. I'm not going to venture a guess about whether the existing stuff is strong enough, as I don't have the knowledge.
 
If anything I would look into finding a 24' i Beam to add additional support to what's already there. I think it would be way to invasive to take out the existing LVLs. And replace with larger ones.

...... or just leave my stripper pole and get some hookers and blow....
 
The original PE that stamped your plan spec'd (5) 2x6's at the bearing points of those LVLs, without knowing the details of what is above (and the calculated live and dead loads) I can only guess from what I see that the calculated loads are too large for the LVL to span 24' without a proper column in the middle of the span (and what you have in place is not a good long term solution). Best bet to clear the span would be to put an I-beam under the LVL's and add 4" pipe columns either end.
 
The pole is actually a piece of 1/4 wall steel pipe with a brass sleeve. Figured it had to be stronger than the 2x6's someone had wedged in there and took up less space. It's not a permanent solution. Just something I had laying around.
 
The short answer is that you need a lolly column or two to break the span. The LVLs can't do it on their own.
 
shawn said:
The short answer is that you need a lolly column or two to break the span. The LVLs can't do it on their own.
Click to expand...

Thanks! I'll just have to work around having a column for now then. Eventually I'll probably put up an I beam. I'd like to have a clear span.
 
General rule of thumb is 1" of depth equals 1' of span for a 2 ply. I know there are a ton of variables but this is about the norm. To get a complete idea of the loading on the beam, we'd need to know how the roof is constructed and braced.

For even just floor loading 2 11-7/8" LVL's are way undersized to clear span 24'. We usually see 3-18's or 2-24's for applications like this.

Just about any lumber yard with an EWP (engineered wood) guy can do a calc. We do it all the time for folks and can get the calc sealed 'based on the loading provided by the customer'.

If you want to screw around with it, Weyerhaeuser offers their Forte software to size joists and beams. It is free to download. Standard loading we use around here is 40psf floor live/15psf dead. 20psf roof live/12psf dead.
 
Just for reference, if you're spanning 22'-0" with an LP LVL, and the LVL is carrying 30'-0" of floor (15'-0" to either side), you can span it with a triple 18" (5-1/4" wide). If the spans get longer than that, the LP chart doesn't provide sizes. Likewise if there are any load-bearing walls contributing to the floor load above, or if the load isn't a simple span in single-family wood framed residential with one floor being supported.

You might find different answers with a different manufacturer, so if you can determine whose LVL you're using, that might help fill the gaps.
 
Oh, and it'd be very interesting to know if there is a thickened footing under your pole. That pole is necessary but probably doesn't offer enough bearing surface to keep the LVL's from crushing and the diameter is pretty small. We usually see a steel column with a larger cap and base used for this or a parallam (laminated) post with cap and base.
 
broncosbybart said:
That pole is necessary but probably doesn't offer enough bearing surface to keep the LVL's from crushing and the diameter is pretty small. We usually see a steel column with a larger cap and base used for this or a parallam (laminated) post with cap and base.
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I actually need to fix some problems like this at our house. Center a lolly column under a pair of parallel beams that are 6" apart, then span the gap with a 2x6" laid on the flat. And splice one of those beams 12" out from the bearing wall. That's cool, right?
 
shawn said:
I actually need to fix some problems like this at our house. Center a lolly column under a pair of parallel beams that are 6" apart, then span the gap with a 2x6" laid on the flat. And splice one of those beams 12" out from the bearing wall. That's cool, right?
Click to expand...

As long as they used some liquid nails, you're golden :)
 
Pull the pole out, go upstairs and jump on that spot. If it doesn't break, it never will :bounce:
 
shelby27604 said:
The original PE that stamped your plan spec'd (5) 2x6's at the bearing points of those LVLs, without knowing the details of what is above (and the calculated live and dead loads) I can only guess from what I see that the calculated loads are too large for the LVL to span 24' without a proper column in the middle of the span (and what you have in place is not a good long term solution). Best bet to clear the span would be to put an I-beam under the LVL's and add 4" pipe columns either end.
Click to expand...


It's possible some of those 5 2x's are being used as squash blocks rather than primarily used for supporting the LVLs. Without looking at the house in person, it's hard to say either way.
 
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