Sizing Beam for Mezzanine

[70-K5]

I'd appreciate some input on my beam sizing and proper spans, something just seems wrong to me.
I'm building a mezzanine or storage loft along the back wall of my pole building. I already have a 12x12 office I built in one of the back corner with a loft on top, what I'm doing is extending the loft all the way across.

It will be roughly 28' wide and 12 feet deep. The back wall has some pretty nice shelving already built in so I'm planning on building a wall in front of the shelves, with studs spaced with the shelf openings about 18" from the back wall to support the 2x8 joists. The shelves will also provide some support for the joists as they are the same height as the top of the new wall.

On the side closer to the front of the garage I want to keep it as open as possible so I can pull a car all the way to the back, under the mezzanine. I didn't want any posts in my building, but I'm resigned to have at least one to support the middle of the mezzine, I'm actually thinking of making the center post a small wall between 2 and 3 feet wide. Good place to run an air outlet, some power, maybe a welding plug etc.

Is there a reasonable size beam that will carry the 13 feet between the office and center support, or do I need to increase the width of the center support or frame in an extra foot or three from the office and the alternate wall?

This is just storage, not planning on having means of elevating anything more than I can carry up a ladder, so no engines or obscenely heavy items, but I'm figuring the 10/dead 40/live load figures for a stable surface. Some calculators said I needed three 2x12's to carry 9'9" with a 12' joist, but when I figure load on a beam, say 14' feet supporting that area of floor it is 3,360 pounds or 240/linear foot, which other calculators say it will carry.

Would someone smarter than me on engineering let me know so I don't end up over/under building.

 

[PoorUB]

Ten foot span is not a big deal. I have put 2 2"x12" LVLs in place when tearing out a wall in a house with a second floor about it.

An other example, ten foot garage door supporting the roof russes? Two 2"x12" LVL, all day long.

I can not imagine two 2"x12" LVLs will not be just fine. the worst is it may bounce, but it will not go anywhere.

 

[70-K5]

I have extra 4x12', or I'd go with #2 2x12's, not interested in cost of lvl.

 

[PoorUB]

IMO, either will be fine.

 

[Dagny]

I made something very similar when lumber was high went in the woods and cut a very nice white oak got 7 18 foot 2x12s then glued and screwed 2 of them together they span 17 feet incredibly solid.

 

[K'ledgeBldr]

I’d do a 12@22 steel I-beam. It will span that distance with no problem (no center support).

 

[mike93lx]

If you don't want to spend money, what you have with a post sounds fine.

This could pretty easily be clear span though, if you were willing to buy a beam

 

[duneslider]

I have 3 2x12's for a span of 13' in my garage and it is very solid

 

[35k0]

We built this 16x20 covered patio a couple years ago and used doubled up 1 3/4" x 16" x 16' LVL 1.9E on each side to make the span from post to post. Hasn't moved an inch, bowed or sagged. Did not want any obstructed views from posts, this worked mint.

 

[70-K5]

I’d do a 12@22 steel I-beam. It will span that distance with no problem (no center sup

The middle support will actually be in a pretty good spot, (right in front of my lift) for a 220 welding plug and an air outlet.

What do you think a beam that size would cost out of curiosity? I've only built with wood and a 16' 2x12 is $49.97 today.

 

[mike93lx]

The middle support will actually be in a pretty good spot, (right in front of my lift) for a 220 welding plug and an air outlet.

What do you think a beam that size would cost out of curiosity? I've only built with wood and a 16' 2x12 is $49.97 today.

Looking at one online price, I'm seeing $432 for a 20 footer. Pricing will vary greatly on location and the specific beam. So with delivery, at least $500 seems like a reasonable enough estimate.

 

[kwb]

Steel is pricing out at just under $1/lb so the beam would be about $286 assuming it isn't a really uncommon size.
I didn't do any math to confirm that an S12x22 beam would span this.

 

[K'ledgeBldr]

What do you think a beam that size would cost out of curiosity? I've only built with wood and a 16' 2x12 is $49.97 today.

The steel I-beam affords you the clear span with pretty much zero defection. You’re not getting that with 2X12’s.
Price, as mentioned previously will vary somewhat- plus there’s delivery and (if you don’t have the means) install fees.

 

[70-K5]

It came out better than I hoped for.
3-2×12 to span the front, 2-2x8's along the back a little tighter.

Decided on 4x4 16ga utility panel for railing, will help avoid necessity of additional lighting up top.

 

[FL Guy]

It came out better than I hoped for.
3-2×12 to span the front, 2-2x8's along the back a little tighter.

Decided on 4x4 16ga utility panel for railing, will help avoid necessity of additional lighting up top.

What kind of wire mesh is that up top?

 

[BearyNelson]

What kind of wire mesh is that up top?

I know this is a bit old but I'd guess it's horse panel.

Same as hog, but thicker gauge and 4x4 openings. Can usually be found wider/taller too.

I used it for building fence panels recessed into dado notches.

 

[aalleexx]

The steel I-beam affords you the clear span with pretty much zero defection. You’re not getting that with 2X12’s.
Price, as mentioned previously will vary somewhat- plus there’s delivery and (if you don’t have the means) install fees.

Probably dumb question, and hate to hijack the thread, BUT; I've got a 30x40' steel building and would like to do a clear span across the 30' to make a 20x30' mezzanine. Would a steel I-beam do 30'? I've got 12' walls with a 4/12 pitch roof. Again, hate to be a pain but any help greatly appreciated.

 

[consti2tion]

Probably dumb question, and hate to hijack the thread, BUT; I've got a 30x40' steel building and would like to do a clear span across the 30' to make a 20x30' mezzanine. Would a steel I-beam do 30'? I've got 12' walls with a 4/12 pitch roof. Again, hate to be a pain but any help greatly appreciated.

I think the span would be dependent on the size of the I-Beam. A span of 30' would likely require something like a W12" 22lb per foot beam.

 

[PoorUB]

Probably dumb question, and hate to hijack the thread, BUT; I've got a 30x40' steel building and would like to do a clear span across the 30' to make a 20x30' mezzanine. Would a steel I-beam do 30'? I've got 12' walls with a 4/12 pitch roof. Again, hate to be a pain but any help greatly appreciated.

I think the span would be dependent on the size of the I-Beam. A span of 30' would likely require something like a W12" 22lb per foot beam.

30 foot span will be closer to a 24" tall beam.

I looked into it years ago on a 24 foot span. I calculated a fairly tall beam, and contacted an engineer to verify. I told him what I came up with and he tapped on his calculator for a minute and agreed with me. Seems to me it was a 24" tall I-beam.

A post in the middle would greatly reduce the beam size. For that long of a span you get a lot of bounce and deflection. Any engineer will account for that and try eliminate it and the beam gets pretty hefty.

 

[strutaeng]

It really depends on the loading, but yeah, a W16, W21 or even a W24 will probably be required to span 30'.

For beams supporting only roof loads, it's common to use W16s. For floors, probably W21 or W24, depending on loads.

W16 can usually only work for a floor if it's in a composite slab floor system (special metal deck filled with concrete, reinforced with mesh or rebar and shear studs welded to the beams.) Or if it's picking up very light floor loads.

Supporting the beam reactions and transferring the loads to the foundation is equally important.

 

[aalleexx]

Ouch!! Might have to halve the span with a support post. Needing all the headroom I can get.

 

[jkuro]

Contact your local steel supplier. They usually have an engineer on staff that will help you size your I beam.

 

[Ole Slewfoot]

At that span, I'd think you can save some material by designing it as a trussed structure if space allows.