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Beam span help

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Ron_J

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I'm trying to get all my ducks in a row, and thinking about my loft/mezzanine. I'd like to have a free span of 15'. The loft are will only he for storage, not living space, and realistically only for decorations and seasonal storage.

I've looked at a few charts for the laminated beams and to be honest, got lost pretty quickly. The loft will be 15'x8'.

Anyone seen a chart or online calculator for beam sizing?

My other option is actually framing in a room with storage above, but I think I'd like to keep the open floor as much as I can.
 
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purediesel

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Your wanting the header size or floor joist size? Every aspect of this needs to be sized properly to be safe. Seems like your wanting the header since it's 15', in that case a double no.1 2x12 would probably span that 15'. Your 8ft floor joist could probably be as small as a 2x6. This is according the southern pine.com.
 
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GMCGarage

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purediesel said:
Your wanting the header size or floor joist size? Every aspect of this needs to be sized properly to be safe. Seems like your wanting the header since it's 15', in that case a double 2x12 would probably span that 15'. Your 8ft floor joist could probably be as small as a 2x6. This is according the southern pine.com.
Click to expand...

Make sure deflection limits are met, dont want to have a sagging beam.
 
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purediesel

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I'd triple the beam up for safety especially since it's only about an extra $15. I'm pretty much planning the same thing but 32'x10'. Triple no.1 2x12's for the header, no.1 2x10's 16" oc floor joists with hangers and triple 2x6 for the support columns.
 
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nadogail

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purediesel said:
I'd triple the beam up for safety especially since it's only about an extra $15. I'm pretty much planning the same thing but 32'x10'. Triple no.1 2x12's for the header, no.1 2x10's 16" oc floor joists with hangers and triple 2x6 for the support columns.
Click to expand...

What he said.
 
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mike93lx

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15' is very substantial. Using the AWC deck guide, even a triple 2x12 would not be sufficient.

I would consider a LVL or LSL beam.

2x8 16OC looks fine for the 8' span. Your ledger connection will be really important too.

I would glue and screw the subfloor as well
 
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Ron_J

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mike93lx said:
15' is very substantial. Using the AWC deck guide, even a triple 2x12 would not be sufficient.

I would consider a LVL or LSL beam.

2x8 16OC looks fine for the 8' span. Your ledger connection will be really important too.

I would glue and screw the subfloor as well
Click to expand...

I was looking at the LVL beams and plan on going that route. Just trying to figure out what will work.
 
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purediesel

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mike93lx said:
15' is very substantial. Using the AWC deck guide, even a triple 2x12 would not be sufficient.

I would consider a LVL or LSL beam.

2x8 16OC looks fine for the 8' span. Your ledger connection will be really important too.

I would glue and screw the subfloor as well
Click to expand...


Do you have a link for their chart on headers, floor edge beams or girder beams? I can only for span charts on joists and rafters.
 
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mike93lx

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purediesel said:
You'll see here under table 14 for floor edge beams that a triple 2x12 can span up to 16' with a 10' supported floor, so with his 8' it'd definitely not a problem. I'm just wondering what to believe, the AWC or the southern pine chart for floor girder beams and headers.


https://www.southernpine.com/span-tables/headers-beams-size-selection-tables/
Click to expand...

To be fair, the AWC guide is for decks. Not sure on what is driving the differences, although southern yellow has a vested interest in selling dimensional lumber...

If it was my shop, i would probably do a two ply LVL and 2x8's with a high quality subfloor like Advantech
 
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theoldwizard1

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purediesel said:
You'll see here under table 14 for floor edge beams that a triple 2x12 can span up to 16' ...
Click to expand...

WOW ! That is a lot of lumber ! Although standard "construction grade" (not SYP) 2x12x16 is <$25. It might actually be cheaper than an LVL. Certainly easier to handle.
 
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p_mori7

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Triple 2x12 makes for a tall beam to span the 15', then add height of your floor joists to span the 8', and then the floor of the loft...

I spanned 14' for a popout on one side of my garage (load bearing outside wall) with a 6x8 rough sawn hemlock beam. it is freaking STOUT. It is supported on either end on 6x6 rough sawn hemlock posts...so real span is 13'-ish. It could have gone 15' no problem.

~Phil.
 
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mike93lx

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p_mori7 said:
Triple 2x12 makes for a tall beam to span the 15', then add height of your floor joists to span the 8', and then the floor of the loft...

I spanned 14' for a popout on one side of my garage (load bearing outside wall) with a 6x8 rough sawn hemlock beam. it is freaking STOUT. It is supported on either end on 6x6 rough sawn hemlock posts...so real span is 13'-ish. It could have gone 15' no problem.

~Phil.
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The joists don't have to sit on top of the beam...not sure why you think that just use joist hangers. The 2x8 can hang at any point in the 2x12 beam. Near the top at the bottom, doesn't matter

And your thoughts on the strength of the hemlock is based on what? That they didn't fail?
 
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Ron_J

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theoldwizard1 said:
WOW ! That is a lot of lumber ! Although standard "construction grade" (not SYP) 2x12x16 is <$25. It might actually be cheaper than an LVL. Certainly easier to handle.
Click to expand...

Just curious, why do you think the 2x12's would be easier to handle than the same size LVL?

From what I am seeing a double 11 7/8" LVL would be the equivalent.

Am I wrong?
 
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mike93lx

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Ron_J said:
Just curious, why do you think the 2x12's would be easier to handle than the same size LVL?

From what I am seeing a double 11 7/8" LVL would be the equivalent.

Am I wrong?
Click to expand...

Dimensional lumber is lighter than lvl's for the same size. You can place the boards individually and join them in place
 
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