Wall construction for clear span

[fwillison]

I'm building a 45 x 65 shop on footings and turn down slab, conventional framing.
I designed the simple rectangular building myself. It will have 12 ft walls and scissor trusses.
I'm hiring a local father/son construction co (basically pole barn builders) to build it.
Will 2x6's 16 in on center be adequate to support the trusses and roof?
Do I need an engineer to review something like this?

Fred

 

[p_mori7]

Did you design the trusses too ?

 

[Thumper68]

If you had the truss co design the trusses then 2x6 on 16's should be fine to support the roof.

 

[J Persons]

my shop is a little smaller at 32'X48' with 12' walls, but I went with 2X6's at 24" on center and engineered conventional trusses on 24" centers.

 

[fwillison]

The trusses will be supplied and engineered by the truss co.
It just seems like a lot of weight on only perimeter walls.

 

[Moose97]

If it were me I would have an engineered design for roof trusses and ceiling joists. How far will these 2X6 ceiling joists span?

 

[Charles (in GA)]

If it were me I would have an engineered design for roof trusses and ceiling joists. How far will these 2X6 ceiling joists span?

He is asking about the stud walls that will be supporting engineered/manufactured roof trusses. He is not asking about the trusses themselves.

Only thing I would mention is to use a double header with staggered joints, but I think thats common knowledge.

Charles

 

[kbs2244]

If your guys have any experience at all they will have a double thick top plate on the wall and place the trusses over the studs.
That has been strong enough all over the country.

 

[mmhouse]

What area are you in? Windstorms and earthquakes can put a lot of lateral stress on a building which means you need to pay attention to shear. Increasing shear strength usually involves solid sheathing on exterior walls or corners (with very specific nailing requirements) and/or metal or wood diagonal bracing. This can be particularly important when a building has no interior partitions to increase shear strength and where there are large openings in walls for overhead doors. This may or may not be an issue for you but it would be worth asking around and maybe running your design by a structural engineer.

 

[Moose97]

He is asking about the stud walls that will be supporting engineered/manufactured roof trusses. He is not asking about the trusses themselves.

Only thing I would mention is to use a double header with staggered joints, but I think thats common knowledge.

Charles

Thanks, I wasn't getting that.

 

[akdiesel]

I have a 40 x 60 clear span shop. It was built by the previous owner but it has 2 x 6 walls. The wall studs are 16" centers but it has them at 8' studs then a double top plate, then an additional 2 x 6 stud wall on top of that to get a 12' 6" ceiling. The top plate on the additional wall is also doubled up.
Not sure if this was in the engineering or it was cost or a second thought for height.
We live in a heavy snow fall area so this is also a concern for the trusses but your truss company will consider all this.

 

[theoldwizard1]

If your guys have any experience at all they will have a double thick top plate on the wall and place the trusses over the studs.
That has been strong enough all over the country.

This !

I would also want the biggest/strongest "hurricane ties" you can get to attach the trusses to the top plates and stud.

 

[CNGsaves]

OP . . . would really help other GJer's if you provided the COUNTRY and STATE where you're building the shop. If in USA, might as well give City and State. Do this by Updating GJ Profile.

Building codes and requirements vary by location, especially if any hurricane wind risk is involved (ie hurricane straps required). Conversely, different issues might be involved for heavy snow areas (depending on type of roof involved, and steepness of roof).

 

[ez-duzit]

Trusses on 2' centers.

Building my own, I might think about doubling the 2x6 full height studs. Doubled header.

 

[theoldwizard1]

Trusses on 2' centers.

Building my own, I might think about doubling the 2x6 full height studs. Doubled header.

Are you going to put the doubled 2x6 studs on 24" centers ?

 

[ez-duzit]

Are you going to put the doubled 2x6 studs on 24" centers ?

Of course. They support the trusses.

 

[mmhouse]

Of course. They support the trusses.

I think many like the idea of having the truss fall directly above a stud but from a structural standpoint is it typically not necessary with a double top plate.

Doubled 2x6 studs are also overkill.

 

[ez-duzit]

I think many like the idea of having the truss fall directly above a stud but from a structural standpoint is it typically not necessary with a double top plate.

Doubled 2x6 studs are also overkill.

Why would you not place the trusses directly over the studs?

For that height, and using 2' centers, I'd double the studs.

 

[mmhouse]

Why would you not place the trusses directly over the studs?

For that height, and using 2' centers, I'd double the studs.

First, because there's little to no reason to do so. Often times studs are on 16" centers and trusses on 24" or 19.2" centers. Having a stud below every truss is not possible, and not necessary.

You'd probably have a stronger structure by putting studs on 16" centers (or 12" centers if you really want to use that much wood) rather than doubling them on 24" centers.

 

[akdiesel]

Trusses on 2' centers.

Building my own, I might think about doubling the 2x6 full height studs. Doubled header.

This is standard practice.
If you go 24" centers you need to consider other building needs.
The standard is 16" centers so most cabinets, plywood, Sheetrock, etc... is set for 16" centers. Although an 8' span will figure into a 16" or a 24" center.

 

[theoldwizard1]

This is standard practice.
If you go 24" centers you need to consider other building needs.
The standard is 16" centers so most cabinets, plywood, Sheetrock, etc... is set for 16" centers. Although an 8' span will figure into a 16" or a 24" center.

I would go 1/2" or 9/16" roof decking (typical around here is 7/16") and extra clips between unsupported **** edges.

As for hanging cabinets, you can always attach a 1x6 cleat to the wall at the studs and then hang the cabinets from this. The smart trick if you are going to do this is cut a 45 on the top edge and attach it with the lower edge toward the wall. Mount another cleat on the back of the cabinets with the slope in the opposite direction. Then you can just hang these cabinets on these cleats with no screws !

 

[jclem40c]

I have a 28x36 enginered building for my shop. It has 2x6 wall studs with scissor trusses and 12 foot walls. double plate on top and sits on 1 course of blocks on top of a monolithic slab which is 6 inches thick with a 1 foot base under the lift. This building is open inside and the roof is load rated for 90 lbs per square foot. Building is in upstate New York so we get wind and snow and the engineer signed off and said it will be fine.

John

 

[theoldwizard1]

I have a 28x36 enginered building for my shop. It has 2x6 wall studs with sissor trusses and 12 foot walls. double plate on top and sits on 1 course of blocks on top of a monolithic slab which is 6 inches thick with a 1 foot base under the lift. This building is open inside and the roof is load rated for 90 lbs per square foot. Building is in upstate New York so we get wind and snow and the engineer signed off and said it will be fine.

Just curious. How were the trusses attached to the tp plate/studs ?

 

[jclem40c]

trusses were toenailed and then had metal straps nailed from truss to the inside of the top plate. Plates are manufactured plates so I guess you would call them hurricane straps. They are about 6 inches long. Wall studs are 16" oc and so are the trusses.


John

 

[fwillison]

What area are you in? Windstorms and earthquakes can put a lot of lateral stress on a building which means you need to pay attention to shear. Increasing shear strength usually involves solid sheathing on exterior walls or corners (with very specific nailing requirements) and/or metal or wood diagonal bracing. This can be particularly important when a building has no interior partitions to increase shear strength and where there are large openings in walls for overhead doors. This may or may not be an issue for you but it would be worth asking around and maybe running your design by a structural engineer.

These are exactly the design concerns I have, and wind shear is an issue in Oklahoma.

 

[fwillison]

I like the idea of a single course of block to get some additional ceiling height and to be able to hose out the shop without getting any wood wet.

How is the bottom plate firmly attached to the block. I was going to use j-bolts in the wet concrete to attach the bottom plate, but this won't work with block.

Fred
Tulsa, OK

 

[ez-duzit]

Why not long J-bolts, precisely placed?

 

[jclem40c]

When they built mine they placed J bolts in the slab and made them long enough that they extended up through the blocks and the plate. Then they poured the slab, layed the block an then poured the cavity in the block around the bolt. Drilled the double plate to match, set the walls on the block and bolted it togeather with a 3x3 galvanized plate and a nut. I then foundation coated the exterior of the block so no sepage into the building and I can hose down the floor with no issues with the OSB walls. This gives me 12'8 from floor to ceiling at the top plate and about 16 feet at the peak with scissor trusses.


John

 

[Kevin54]

2 x 6 walls @ 16" on center, double top plate which is pretty much mandatory every where will be more than adequate to hold up your trusses. Look at it this way, walls like that hold up second stories of houses.

 

[WNYflyer]

When they built mine they placed J bolts in the slab and made them long enough that they extended up through the blocks and the plate. Then they poured the slab, layed the block an then poured the cavity in the block around the bolt. Drilled the double plate to match, set the walls on the block and bolted it togeather with a 3x3 galvanized plate and a nut. I then foundation coated the exterior of the block so no sepage into the building and I can hose down the floor with no issues with the OSB walls. This gives me 12'8 from floor to ceiling at the top plate and about 16 feet at the peak with scissor trusses.


John

Sounds like your shop was built by a contractor who really knew what he was doing.

 

[MScott]

If you are really concerned about the strength of the wall, you might consider doing what I did although strength was not the reason. My original plans called for scisor trusses on 10 foot+ walls (2x6 @ 24") to give me 12 foot ceilings (needed for a lift.) I had started the walls before having the floor poured and, when I was about to add the second top plate, I measured the height of the wall to the floor. I found I was only 7 1/2 inches shy of the 12 feet I needed. Apparently either the floor was lower than expected or the foundation was higher.
I decided to add a 2 x 8 'header" around the entire wall before attaching the second top plate. (double 2x8s on edge with spacers) This gave me a height of over 12 feet so that I could use regular trusses instead of scisor trusses. (cheaper, easier to install and easier to insulate.)
While my purpose was only to increase the wall height, the increase in strength is immense and would certainly allay any fears of being able to hold the weight of trusses.