Mezzanine framing specs

[2011laramie]

Hey guys,

Im getting ready to start framing my 14x24 mezzanine in my shop. I feel like the engineer way over spec'd the mazzanine, but im no engineer so i cant argue what he has drawn. Im also not dealing with him again... bad service.

Im planning on moving the stairs flush to the front for a solid lvl across, but i would think i should be able to use lumber instead of tji joists.

What does everyone else use for a 14ft span?

The lumber yard said 2x12 would be 20 dollars a board cheaper than a tji joist. That makes a couple hundred dollar difference.

 

[RVDan]

2x10 select structural is legal for 14 feet

 

[Ggg]

I'm not a structural engineer, but I do deal with TJI joists on a regular basis, as a Fireman. I wouldn't use TJI's to build anything. Have you looked into steel I beams? It would save some ceiling room below.

 

[RVDan]

Although regular lumber might be cheaper, you'll need more of it, you can go with bigger OC spacing with the TJI.

 

[firebirdparts]

2 x 10's. 16" centers would be "normal" for a 14 foot span, whatever the live load of a house is. That's what most of us are living on, anyway.

You can see that the engineer used 16" centers anyway. I have no idea why he didn't use regular lumber.

 

[ard]

The lumber yard said 2x12 would be 20 dollars a board cheaper than a tji joist. That makes a couple hundred dollar difference.

Vote for TJI... $20 for 20 boards isnt a big deal

2x10 select structural is legal for 14 feet

Also the difference between 'select structural' and TJI might not be $20...

 

[RocketScott]

You would be fine with 2x12, probably 2x10, on 16" centers for that span.

Tji can possibly do the same thing at 24' centers.

Price it out both ways. It's not like it will fall down. It might be bouncy, but whatever you are storing up there won't mind.

 

[tomtomgt356]

What did you tell him you would be storing up there? Engineers design to a specified load. A machine shop, or storing engine blocks and transmissions will require a stronger structure than storing Christmas decorations and bicycles.

 

[theoldwizard1]

Google Search for "span table". It will tell you what size lumber you need for what load over what span. Typically they list fir both 16" and 24" O.C.

Separate table for tji.

If this is a DIY or small crew job, tji are SO MUCH LIGHTER !

Remember, joists sit ON TOP of beams (or are attached to the face of beam with appropriate brackets and fasteners) and beams sit ON TOP of posts. You can notch them into the post, but never bolt them to the face of a post. Attaching a ledger board to the face of existing studs is not sufficient unless you place posts under the ledger.

 

[The Tool Tyrant]

TJI's are far superior to sawn lumber, especially nowadays with the fast growth trees being used for lumber.

TJI's are straight, stay straight, UNIFORM in size and lightweight. Sawn lumber can vary in width by 1/2", some may be straight, although 99% will have a 'crown' that must be placed up when installing. The engineer is correct.

 

[Toomanytools?]

I'm not a structural engineer, but I do deal with TJI joists on a regular basis, as a Fireman. I wouldn't use TJI's to build anything. Have you looked into steel I beams? It would save some ceiling room below.

You need to expand/explain your answer, why would you not use them? They burn easy, cost, you can't spell TJI ? Just wondering.

 

[NebrTd]

You need to expand/explain your answer, why would you not use them? They burn easy, cost, you can't spell TJI ? Just wondering.

I believe his comment was based solely on being a firefighter. They do not last very long in a fire. It makes sense by just looking at them. Hopefully if a fire would need to be put out, there would be no reason to go up on the loft.

I used them in my loft build. They are light which makes them very nice for a couple guys when they are almost 20'.

 

[2011laramie]

So the inspector said 2x12 would be fine, would give it about a 80lb load.

 

[Lelandwelds]

I feel like the engineer way over spec'd the mazzanine, but im no engineer so i cant argue what he has drawn.



That makes a couple hundred dollar difference.

Most things have a safety margin of 2 to 1, 5 to 1, or 10 to 1 by design. $200 on a structure ain't ****. Follow the plan as designed. You paid for it.

TJI's are far superior to sawn lumber, especially nowadays with the fast growth trees being used for lumber.

TJI's are straight, stay straight, UNIFORM in size and lightweight. Sawn lumber can vary in width by 1/2", some may be straight, although 99% will have a 'crown' that must be placed up when installing. The engineer is correct.

What he said.

 

[Ggg]

I believe his comment was based solely on being a firefighter. They do not last very long in a fire. It makes sense by just looking at them. Hopefully if a fire would need to be put out, there would be no reason to go up on the loft.

I used them in my loft build. They are light which makes them very nice for a couple guys when they are almost 20'.

Yes you are corect. They don't last long at all in a fire or if they get wet. I don't need to be up on that loft for the TJI failure to kill me. I very well may be under it fighting a fire or searching for victims.

 

[Steveodle]

My mezzanine is 14x25 built this year, in Illinois, self built. LVL on 25 ft. Side w. Pole support in center and 2x10x14 ON 24"CENTERS.
Engineering said ok and 3/8" deflection using these,
I sheeted with. 3/4" t+g , nailed and glued.