Mezzanine design/engineering help.

[Adittmer]

Ok guys the time has come where I’d like to add xtra space in our shop and build the mezzanine I had envisioned.
I have a general idea of how I might construct it but have some questions on a few things.

above are some pictures for you guys to see what I’m working with here.
When the building was put up I asked the builder to install a ledger board for a mezzanine in the wall dividing the shop from the cabin. They ended up using large ring shank nails to attach a 2x10” to the posts rather then bolt an lvl beam or the like to it.

My thoughts now are to buy a 36’ 1 3/4 x 9.5” lvl beam and bolt it over the 2x10” ledger board with 1/2 or larger lag bolts into the columns in that wall? I guess the other thing that comes to mind is to pull that 2x10” off but I know it’s going to be a pain in the *** with the ring shank nails and I don’t see how it would affect it if kept on??

Second question is that I will set the 6x6 treated post into the ground 4ft deep on a concrete puck then sack Crete and back fill. I would set the posts holding the mezzanine out at 8ft in line with the posts on the side of the shed and I was then thinking of buying another 36’ lvl as a header to run across the posts and have my floor joists attach to etc. my plan is to cantilever 2x10 floor joist 2ft over the header for a total size of 36’ x10’ mezzanine.

So big question is can one lvl 9.5 x1 3/4” work as the header and how many posts will I need to carry the load over the 36’ wide of the mezzanine?

I won’t be parking cars on top of it but I might put some 400 or 500lbs things and also shelving for storage to clean up the shop floor etc.


Sorry for the long rambling lol




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[GMCGarage]

Running a quick calc I get post spacing about 11 feet. This is based on 40 psf live load. You would be better buying 4 individual beams, should be cheaper.

Goto a 11.25" deep beam, easily get away with only 2 posts.

I based this design on Microlam LVL 2.0 from Truss Joist (Weyerhaeuser)

 

[kmacht]

I think you are overbuilding here. What is wrong with the 2x10 header? The ring shank nails are wrong but why not just put some lag's through it into the posts? A LVL isn't needed here since the 2x10 is supported every 8 feet by being lagged to the posts. No need for your posts to sit on a 4' deep concrete pier either. You are building indoors and don't need to worry about the frost heave. If you did, your concrete floor would be buckling. What you need is surface area, not depth. Think, 3x3 pads 8" thick instead.

 

[ard]

I think you are overbuilding here.

This should be the page banner on GJ.....

 

[bczygan]

Ok guys the time has come where I’d like to add xtra space in our shop and build the mezzanine I had envisioned.
I have a general idea of how I might construct it but have some questions on a few things.

above are some pictures for you guys to see what I’m working with here.
When the building was put up I asked the builder to install a ledger board for a mezzanine in the wall dividing the shop from the cabin. They ended up using large ring shank nails to attach a 2x10” to the posts rather then bolt an lvl beam or the like to it.

My thoughts now are to buy a 36’ 1 3/4 x 9.5” lvl beam and bolt it over the 2x10” ledger board with 1/2 or larger lag bolts into the columns in that wall? I guess the other thing that comes to mind is to pull that 2x10” off but I know it’s going to be a pain in the *** with the ring shank nails and I don’t see how it would affect it if kept on??

Second question is that I will set the 6x6 treated post into the ground 4ft deep on a concrete puck then sack Crete and back fill. I would set the posts holding the mezzanine out at 8ft in line with the posts on the side of the shed and I was then thinking of buying another 36’ lvl as a header to run across the posts and have my floor joists attach to etc. my plan is to cantilever 2x10 floor joist 2ft over the header for a total size of 36’ x10’ mezzanine.

So big question is can one lvl 9.5 x1 3/4” work as the header and how many posts will I need to carry the load over the 36’ wide of the mezzanine?

I won’t be parking cars on top of it but I might put some 400 or 500lbs things and also shelving for storage to clean up the shop floor etc.


Sorry for the long rambling lol




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Clear span or posts? If posts, how many? Or will a wall go under part or all of it?

Bill

 

[GMCGarage]

Clear span or posts? If posts, how many? Or will a wall go under part or all of it?

Bill

His second to last sentence asks about post spacing.

 

[Adittmer]

Clear span or posts? If posts, how many? Or will a wall go under part or all of it?



Bill

Post holding up the header, no wall. I’m unsure on the post spacing tho.


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[theoldwizard1]

My thoughts now are to buy a 36’ 1 3/4 x 9.5” lvl beam and bolt it over the 2x10” ledger board with 1/2 or larger lag bolts into the columns in that wall?

Leave that board there. Attach joist to this with appropriately sized joist hangers and fasteners (not plain nails).

You need to support that 2x10 with some post. You can use 2x6, flat to the wall, spaced every 24" O.C. I don't know that that bottom board is, but if it rest on the concrete, these "posts" can rest on it.

If the floor of the mezzanine is going to be 36'x10' all of the span tables I find recommend a maximum of 24" O.C. spacing for the beams (36'). The existing 2x10 covers the back, but this would be 5 9.5 LVLs and post every 12' including support at the end. You could go with 18' post spacing but your load would drop from 274 to 80 for 9.5 LVLs.

The old rule of thumb for cantilever overhang is no more than 30% of the length of the joist so a 2' overhang would be fine.

 

[matt_i]

The fastener I would pick is GRK-RSS structural screw, 5/16" dia x whatever length you can use without piercing the outside of the next timber. There are expected shear values which are tabulated; subjectively I feel its stronger than any lag bolt, it cuts a hole for the threads rather than creating a big conical wedge that's prone to splitting and reducing clampload to near zero.

If you can thru-bolt it with "machine thread" hex head bolts I would also consider that a very good option, but it depends on access.

Ring shanks come out just fine with a heavy cats paw or a carpenter's crow-bar, a little scarring on the timber to get a bite under the head, but once they are moving they can be extracted like any other nail.

 

[Adittmer]

Leave that board there. Attach joist to this with appropriately sized joist hangers and fasteners (not plain nails).



You need to support that 2x10 with some post. You can use 2x6, flat to the wall, spaced every 24" O.C. I don't know that that bottom board is, but if it rest on the concrete, these "posts" can rest on it.

Dirt floor as of now. Are you saying to nail or bolt 2x6” on the sheetrock under that 2x10” to support it? Is bolting it to the post behind with large lags or grk’s isn’t enough? I’m asking cause I don’t know. Thanks



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[bczygan]

Post holding up the header, no wall. I’m unsure on the post spacing tho.


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You have a choice of no posts, one post or more. I wouldn't use more than 2.

The less posts, the deeper the beam. What are your heights?

As mentioned above, the 2x10 will be fine as a ledger if it is fastened properly and also supported in enough places to cut the spans adequately.

And the joists need to be properly sized. Will the mezzanine have a railing or a wall at the edge? How will it be accessed? Stair or ladder or lift?

Will the heavy weights you mentioned ever be set on the edge of the mezzanine, even while loading them up there?

Bill

 

[Adittmer]

You have a choice of no posts, one post or more. I wouldn't use more than 2.

The less posts, the deeper the beam. What are your heights?

As mentioned above, the 2x10 will be fine as a ledger if it is fastened properly and also supported in enough places to cut the spans adequately.

And the joists need to be properly sized. Will the mezzanine have a railing or a wall at the edge? How will it be accessed? Stair or ladder or lift?

Will the heavy weights you mentioned ever be set on the edge of the mezzanine, even while loading them up there?

Bill

How would I use no posts?
I was planning on using 2x10” for the floor hoist spaced 16” on center.
There will be no railing or maybe some type of removable type built of 2x4” or 2x6”
Not sure on the access yet for the stairs, still trying to figure that part out and not eat up the depth of my shop and or block my side over head door.


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[sanddan]

My shop has a mezzanine/loft that takes up one 12'x36' bay. I went to a local lumber yard that did design consultation to help me spec out the proper sizes for the beams and lumber. It is storage rated and uses 4x10 beams that span between the posts. I had the pole barn builder install 2 posts when the building was built. The cross joists are 2x8 on 16" centers and span 12'. The joists are on 12" centers in the bay where the stairs are due to the longer span. At the time I was building this I thought it was over engineered, maybe the main beams are, but the floor has some "spring" to it so maybe not. If you are interested I can get more pics.


The loft has been up there for over 20+ years and has a fair amount of "stuff" stored there so I'm glad I went more heavy duty. The only thing I didn't do back then is build hand rails for the stairs. Back then I didn't need the extra support when going up and down but I really wish I had them now. It's on my list to add sooner rather than later.

 

[Adittmer]

My shop has a mezzanine/loft that takes up one 12'x36' bay. I went to a local lumber yard that did design consultation to help me spec out the proper sizes for the beams and lumber. It is storage rated and uses 4x10 beams that span between the posts. I had the pole barn builder install 2 posts when the building was built. The cross joists are 2x8 on 16" centers and span 12'. The joists are on 12" centers in the bay where the stairs are due to the longer span. At the time I was building this I thought it was over engineered, maybe the main beams are, but the floor has some "spring" to it so maybe not. If you are interested I can get more pics.





The loft has been up there for over 20+ years and has a fair amount of "stuff" stored there so I'm glad I went more heavy duty. The only thing I didn't do back then is build hand rails for the stairs. Back then I didn't need the extra support when going up and down but I really wish I had them now. It's on my list to add sooner rather than later.

Thank you for the picture and info. This really helped. If you had some more pictures of the under side of it and how you attached the beam to the posts I’d love to see that!

Thanks again guys.



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[bczygan]

How would I use no posts?
I was planning on using 2x10” for the floor hoist spaced 16” on center.
There will be no railing or maybe some type of removable type built of 2x4” or 2x6”
Not sure on the access yet for the stairs, still trying to figure that part out and not eat up the depth of my shop and or block my side over head door.


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You use no posts by having the beam clear span from one side of the building to the other. It simply means you need a deeper beam with maybe an additional ply. Does that appeal to you, or are posts no hindrance?

The other thing I want to address is the idea of a cantilever. If you are lifting heavy things up on to the cantilevered portion, it has a lot less load carrying capacity. I recommend placing a post at the 10' point in your 2 side walls, to support the beam with no cantilever of the floor joists. This makes your entire mezzanine equally capable of supporting any loads.

And pay attention to the post above that mentions how to redo the ledger beam. Bolt it to the studs with 3/8" lag screws into studs, a maximum of 24"o.c. For extra support, and to cut the span, place 2x6's on the flat, against the wall vertically, under the ledger boards at 4'o.c.

When you decide if you want a clear span beam or posts (And number of posts), then the beam can be specified and sized.

If clear span is desired, then use a 3-ply 1 3/4x18 LVL. Or go steel.

With one post in the middle, use a 2-ply 1 3/4x11 1/4 LVL beam.

For floor joists I would use 2x8's at 12"o.c. Use 3/4" T&G plywood floor sheathing glued and screwed.

Bill

 

[theoldwizard1]

You need to support that 2x10 with some post. You can use 2x6, flat to the wall, spaced every 24" O.C. I don't know that that bottom board is, but if it rest on the concrete, these "posts" can rest on it.

Dirt floor as of now. Are you saying to nail or bolt 2x6” on the sheetrock under that 2x10” to support it? Is bolting it to the post behind with large lags or grk’s isn’t enough? I’m asking cause I don’t know.

Those posts were never designed to carry that amount of load !

Rip the 2x10 out an install another LVL beam supported like the other and NOT supported by those posts !

 

[theoldwizard1]

As mentioned above, the 2x10 will be fine as a ledger if it is fastened properly and also supported in enough places to cut the spans adequately.

Come on Bill ! That is a 36' span, with 6 4x4 (?) posts that are 14' (?). Not any cross bracing and not even equally spaced !

If they were 6x6, spaced 4' O.C. and adequate cross bracing then I would agree !

 

[bczygan]

Come on Bill ! That is a 36' span, with 6 4x4 (?) posts that are 14' (?). Not any cross bracing and not even equally spaced !

If they were 6x6, spaced 4' O.C. and adequate cross bracing then I would agree !

Each 4x4 column will support 5500#. The load on them is 1800#. They are braced by the mezzanine.

Bill

 

[GMCGarage]

Those posts were never designed to carry that amount of load !

Rip the 2x10 out an install another LVL beam supported like the other and NOT supported by those posts !

Come on Bill ! That is a 36' span, with 6 4x4 (?) posts that are 14' (?). Not any cross bracing and not even equally spaced !

If they were 6x6, spaced 4' O.C. and adequate cross bracing then I would agree !

Each 4x4 column will support 5500#. The load on them is 1800#. They are braced by the mezzanine.

Bill

I think we are splitting hairs. We dont even know what the design load is. I think the OP can walk away knowing he has options, just needs to make sure it properly designed like his original building.

 

[larry_g]

In my build below posts 11-13 show my mezzanine and how it was built. Those are 4x12 spanning the gap between the inner posts held in with blind hangers. The storage wall replaces one section and has worked well for me. Under the ledger in your building you could build something similar to my storage wall to support the ledger you have and get storage to boot..

lg
no neat sig line

 

[theoldwizard1]

In my build below posts 11-13 show my mezzanine and how it was built. Those are 4x12 spanning the gap between the inner posts held in with blind hangers.

Those front hangers look like they are for a 2x8 not a 2x12 ! By fastening the 4x12 to the post with a hanger you have greatly reduced the load capacity of that front beam. Don't be holding any dance parties upstairs !

Total width is 36', correct ? So those 6x6 post are 12' apart. What is the back ledger (also a 4x12 ?) and how is it attached to the rear wall posts ? It looks like there are some 2x6 "blocks" (?) face nail to those post to "help" what ever fasteners you used to attach that ledger.

2x10 joists ? How long ? 16" O.C. ?

 

[theoldwizard1]

In my build below posts 11-13 show my mezzanine and how it was built. Those are 4x12 spanning the gap between the inner posts held in with blind hangers.

Those hanger holding that front 4x12 are much smaller than the 12" board. The look they are for a 4x8. By using a hanger to attach that 4x12 to the post you have greatly reduced its load carrying capacity. Don't be holding any dance parties upstairs !

Total width is 36', correct ? So those 6x6 post are 12' apart. What is the back ledger (also a 4x12 ?) and how is it attached to the rear wall posts ? It looks like there are some 2x6 "blocks" (?) face nail to those post to "help" what ever fasteners you used to attach that ledger.

2x10 joists ? How long ? 16" O.C. ?

 

[theoldwizard1]

Each 4x4 column will support 5500#. The load on them is 1800#. They are braced by the mezzanine.

Bill

I would "feel better" if he face nailed a 2' long 2x4 on the front of each of those posts under that ledger. Lots of nails and lots of construction adhesive !

 

[larry_g]

Those hanger holding that front 4x12 are much smaller than the 12" board. The look they are for a 4x8. By using a hanger to attach that 4x12 to the post you have greatly reduced its load carrying capacity. Don't be holding any dance parties upstairs !

Total width is 36', correct ? So those 6x6 post are 12' apart. What is the back ledger (also a 4x12 ?) and how is it attached to the rear wall posts ? It looks like there are some 2x6 "blocks" (?) face nail to those post to "help" what ever fasteners you used to attach that ledger.

2x10 joists ? How long ? 16" O.C. ?

Cruise on down to post #29 and you'll see a stud wall under that 4x so the hanger is not supporting all the weight.

 

[GMCGarage]

Those hanger holding that front 4x12 are much smaller than the 12" board. The look they are for a 4x8. By using a hanger to attach that 4x12 to the post you have greatly reduced its load carrying capacity. Don't be holding any dance parties upstairs !

Total width is 36', correct ? So those 6x6 post are 12' apart. What is the back ledger (also a 4x12 ?) and how is it attached to the rear wall posts ? It looks like there are some 2x6 "blocks" (?) face nail to those post to "help" what ever fasteners you used to attach that ledger.

2x10 joists ? How long ? 16" O.C. ?

Depending on the hanger, some can get upwards of 5-6K of load. Might ask him what he used and then figure it out.

 

[theoldwizard1]

Depending on the hanger, some can get upwards of 5-6K of load.

Well, you are correct of course. I ASSUMED he used a Simpson HUC412 which is rated for MUCH LESS LOAD !

 

[bczygan]

I would "feel better" if he face nailed a 2' long 2x4 on the front of each of those posts under that ledger. Lots of nails and lots of construction adhesive !

I would feel better if they reached all the way to the floor!

Bill

 

[theoldwizard1]

I would feel better if they reached all the way to the floor!

So would I, but there is no floor !

 

[GMCGarage]

Well, you are correct of course. I ASSUMED he used a Simpson HUC412 which is rated for MUCH LESS LOAD !

What did he use when you asked? Is it SAFE?

 

[theoldwizard1]

What did he use when you asked? Is it SAFE?

This makes it safe.

Cruise on down to post #29 and you'll see a stud wall under that 4x so the hanger is not supporting all the weight.

Of course if that was his plan all along, he certain did NOT need a 4x12 ! 2x10 sitting on a structural stud wall would have been enough as the wall is carrying the load.

 

[GMCGarage]

This makes it safe.


Of course if that was his plan all along, he certain did NOT need a 4x12 ! 2x10 sitting on a structural stud wall would have been enough as the wall is carrying the load.

I assume so.

 

[larry_g]

Of course if that was his plan all along, he certain did NOT need a 4x12 ! 2x10 sitting on a structural stud wall would have been enough as the wall is carrying the load.

You are correct as always master. However the 4x was free and the 2x would have to have been purchased.

lg
no neat sig line

 

[theoldwizard1]

You are correct as always master. However the 4x was free and the 2x would have to have been purchased.

FREE is Good !

 

[Low50s]

I am following this as I want to make a 8x18 free standing Loft/mezz in my space and OP looks like you have to put your ladder in your truck like myself

 

[rayra]

OP better read the engineering notes on an LVL, he'll likely find that its load rating is much reduced if he uses it as a ledger, piercing it with bolts. You'd do far better to sister some dedicated support posts for the LVL to your barn posts.

 

[Fisherguy]

(I wonder if Adittmer is a little confused at this point?)

 

[G8rDuc]

Ever finish this?

 

[Fisherguy]

I used 3 - 12" LVL beams for my mezzanine, haven't got the shop all setup yet but I like how the mezzanine turned out.