Seeking advice on storage loft build

[CooperFarm]

Good morning GJers! I've recently finished a 26'x38'x12' pole barn. Concrete is in and has cured for about three weeks. Now I am in the planning stage for a storage loft that will span the entire width of the back 8' of the building.
Anyone have experience with engineered lumber/wood I-beams? My research has led me to believe 11-7/8" TJI 560 (Weyerhaeuser) on 12" centers will handle the 25' clear span with acceptable deflection, and a 40psf live/20psf dead load. I'll be using double 2x12 headers supported by 6x6 posts on both ends. I've also read that thicker ply as decking (3/4") will add rigidity and help minimize deflection, but is it worth it with the added weight? Any thoughts? (Keep in mind the overall dimensions will be 25'x8'. Also I won't be putting anything super heavy up there. No engine blocks or bullion )
Thanks in advance

 

[theoldwizard1]

Skip the headers on the ends. The I-beams should rest directly ON TOP of the 6x6 post. This is CRITICAL ! If you can not do this, then connect the I-beam to the 6x6 using the appropriate joist hanger. 4x4 is probably adequate depending on what your load is.

3/4" decking will not add much rigidity, so it is probably overkill. Whatever plywood you decide to use, you need a 2x4 (or 2x6) cross braces between your I-beams very 4' to nail down your decking. Use joist hangers, but you will have to "build out" the center of the I-beam (plywood and construction adhesive) so that it flush with the width of the top and bottom. I would also use the

The posts should be connect to the floor with appropriate brackets and I would add a diagonal 2x6 across all of the post to prevent them from moving. Use the proper structural screws and an impact. It make the installation of the bracket SO much easier

 

[CooperFarm]

Skip the headers on the ends. The I-beams should rest directly ON TOP of the 6x6 post. This is CRITICAL ! If you can not do this, then connect the I-beam to the 6x6 using the appropriate joist hanger. 4x4 is probably adequate depending on what your load is.

3/4" decking will not add much rigidity, so it is probably overkill. Whatever plywood you decide to use, you need a 2x4 (or 2x6) cross braces between your I-beams very 4' to nail down your decking. Use joist hangers, but you will have to "build out" the center of the I-beam (plywood and construction adhesive) so that it flush with the width of the top and bottom. I would also use the

The posts should be connect to the floor with appropriate brackets and I would add a diagonal 2x6 across all of the post to prevent them from moving. Use the proper structural screws and an impact. It make the installation of the bracket SO much easier

Thanks for the reply, but I'm a little confused. I guess I should have said "ledger" instead of "header", though it won't be attached to the wall on either side. I was going to use double 2x12s lap jointed to the top of the 6x6 posts (anchored into the concrete), and run the I-beams either on top of the 2x12s, or with appropriate hangers. Are you saying I need a post under every I-beam?

 

[dfiler2]

I did basically the same thing last year for my shop. I used 11 7/8 I-Joists with a 26' span, then 3/4 T&G OSB, I think it was called Sturdi-Floor, glued and nailed on top. The only thing different is I had 2" of spray foam applied underneath which would add some strength. It is a very solid floor and even with weight on top, I have not seen any movement.

It seems the 2x12's would work fine, but check with a local lumber yard or on line for some span tables which should show you how far apart for the 6x6's. I think I would consider a 2x4 wall.

 

[CooperFarm]

I did basically the same thing last year for my shop. I used 11 7/8 I-Joists with a 26' span, then 3/4 T&G OSB, I think it was called Sturdi-Floor, glued and nailed on top. The only thing different is I had 2" of spray foam applied underneath which would add some strength. It is a very solid floor and even with weight on top, I have not seen any movement.

It seems the 2x12's would work fine, but check with a local lumber yard or on line for some span tables which should show you how far apart for the 6x6's. I think I would consider a 2x4 wall.

I'm only spanning 8' with the double 2x12, so I think I'm good there, but I'll dig a little deeper to be extra sure (I'm certainly no engineer). How did you support/hang your I-beams? Thanks for the input

 

[theoldwizard1]

Thanks for the reply, but I'm a little confused. I guess I should have said "ledger" instead of "header", though it won't be attached to the wall on either side. I was going to use double 2x12s lap jointed to the top of the 6x6 posts (anchored into the concrete), and run the I-beams either on top of the 2x12s, or with appropriate hangers. Are you saying I need a post under every I-beam?

A post, even a 4x4, under each joist would be best.

What would the spacing be on the 6x6s ?

A ledger is okay IF it rests ON TOP of the posts. Many people will through bolt it to the post. This is not correct. I would use an appropriate bracket to attach the ledger to the post.

 

[dfiler2]

I'm only spanning 8' with the double 2x12, so I think I'm good there, but I'll dig a little deeper to be extra sure (I'm certainly no engineer). How did you support/hang your I-beams? Thanks for the input

This is done inside another building and I put up a 2x6 wall at each end. I went with 2x6 because the area is insulated and heated. I have one 10' door coming into the area and I used 3 2x10's with 1/2" ply between to get the 5 1/2 inch width I needed and it is very solid.

 

[CooperFarm]

A post, even a 4x4, under each joist would be best.

What would the spacing be on the 6x6s ?

A ledger is okay IF it rests ON TOP of the posts. Many people will through bolt it to the post. This is not correct. I would use an appropriate bracket to attach the ledger to the post.

The spacing on the 6x6s would be 8', (total loft area 25'x8'). I had planned on notching the 6x6s so that the double 2x12 would sit on/in the top of the 6x6s and then bolting through. So what you're saying is that I need support in the form of 4x4s or a framed wall under the whole 8' span? I apologize, I'm very much a visual learner, so it's difficult for me to envision the correct setup. I guess I'm not sure of the spacing on the support posts for the 8' span.

 

[theoldwizard1]

I would not be comfortable with 2 - 2X12s spaced 8' apart, but it depends on your load. At 40psf live/20psf dead load someone smarter than me will have to make that call. My "gut" say put another post in so that your span is 4'.

Notching the top of the 6x6, so that both 2x12s rest in the notch is also acceptable.

 

[CooperFarm]

Thanks y'all for your experience and wisdom. I'll keep checking back, but for now I'll assume I need to add at least one more post, or possibly just frame out end walls.
As a bit of a side-note: I cannot believe the price differences in I-joists!! Never ceases to amaze and baffle me how one supplier can be 3x the price of another one 15 miles away!

 

[dfiler2]

I was surprised to see my local lumberyard beat Menard's pricing on I-joists.

 

[countrytech]

I'm in the process of adding a 12x20 storage loft in my pole barn. We are putting a 4x4 post every 4ft along each side of the loft with 2x10's attached with GRKs to the side of the posts and spanning the 4' distance. Then we're using 12-foot 2"x8"s with hangars every 12" on center.

I don't know what you are planning to store in your loft, but I ran my plan past a local contractor friend and was told that my supports are overkill, and the 2x10's could easily span 8'.

*Disclaimer, I'm not an engineer, and I didn't stay at a Holiday Inn last night

 

[CooperFarm]

I was surprised to see my local lumberyard beat Menard's pricing on I-joists.

Don't even get me started. The lowest price I've found is still more than twice that of Menards. Too bad the closest Menards is 500 miles away!

 

[theoldwizard1]

Thanks y'all for your experience and wisdom. I'll keep checking back, but for now I'll assume I need to add at least one more post, or possibly just frame out end walls.

With less space between posts, you could drop down to doubled 2x10s and save a few bucks.

 

[theoldwizard1]

I'm in the process of adding a 12x20 storage loft in my pole barn. We are putting a 4x4 post every 4ft along each side of the loft with 2x10's attached with GRKs to the side of the posts and spanning the 4' distance.

I am Old School. I don't like ANY load carrying member attached to the FACE of any post, I don't are what kind of fastener you are using. Put it in top of the post and mount it there with a proper bracket or notch the top of the post so that the ledger rests IN the notch.

 

[countrytech]

I am Old School. I don't like ANY load carrying member attached to the FACE of any post, I don't are what kind of fastener you are using. Put it in top of the post and mount it there with a proper bracket or notch the top of the post so that the ledger rests IN the notch.

The more I think about it, the more I wish I had insisted on doing this, but now that the loft is up and the flooring installed, it's a little late. I reckon that's the downside of relying on "free" help, and the help has their own strong opinions of how they want to do things.

I may go back and lag some angle iron supports under the 2x10s at the posts just for extra insurance.

 

[MagKarl]

Could you build two regular stick frame stud walls 8 feet long that could be nailed between your posts, in the same plane? They would sit on your slab edge and support the TGI's, and the inside faces of the studs plane with the posts in case you decide to sheet the inside someday.

 

[theoldwizard1]

I may go back and lag some angle iron supports under the 2x10s at the posts just for extra insurance.

Nail a 2x4 on the face of the post tight between the ledger and the floor. Not perfect, but it would make me sleep better at night if it was my place.

 

[YukonXL04]

keeping an eye on this as I will be doing something similar.

Can you put the 4x4 or 6x6 posts inside the wall on either side?

 

[CooperFarm]

With less space between posts, you could drop down to doubled 2x10s and save a few bucks.

I'm still debating whether I'm going to run the I-joists on top, or face mount with hangers. I also failed to mention (because I kind of forgot about it) that there is a 6' window on one side of where the loft will be, so I think I'll have to stick with the 2x12s.

 

[CooperFarm]

keeping an eye on this as I will be doing something similar.

Can you put the 4x4 or 6x6 posts inside the wall on either side?

I'll probably go with 6x6 in the corners and 4x4's in between.
I'm a bit mired in auto repair at the moment so I haven't had time to respond (Grand Cherokee brake lines are a *****) but I'll be ordering material next week, and I'll post some pics of the space too. Thanks again for everyone's input

 

[CooperFarm]

Finally back on track, sorta. Brake line is in, replaced a trans cooler line on a Malibu, new starter on the old Bronco...what else could go wrong?
Will be ordering material today, and I had one more question before I drop $100 on hangers: To face mount or not to face mount? Should I be concerned about the structural integrity being less if I face mount rather than top mount (on double 2x12)? BTW, I believe the hangers call for 10 - 10d nails per hanger, plus 2 in the flange...

 

[Fred.]

I'm planning to build a second floor in my garage.
I'll be using 1-3/4' X 14" LVL as my ledger and 14" TJI 560 with all joist mounted with top flange hangers.