Sway in pole barn roof?

[mike758]

I’m currently building a 24x40x10 pole barn, and I’m almost done framing. The poles are 4x6s, spaced 8’ OC on sides, and then there’s two towards the middle on each end. My current concern is that when I get on the roof, I can sway it around a little bit. The whole roof assembly is rock solid, I’m specifically talking about like the top of the poles bending a little. I’m not sure if there’s any additional bracing I can add, or if the metal siding might sure some things up.

 

[matt_i]

Do you have all of the wall and roof purlins on?

Also they should be double-nailed in my opinion (2 nails wherever it crosses another framing member) as otherwise there's a perfect pivot point for a parallelogram.

 

[outdoorspace]

The roof metal will add a lot of strength in shear, especially if screwed on the flats. Ideally the purlin nails should also be shot at an angle to improve pull out resistance, but this wouldn't increase stiffness.

 

[GMCGarage]

I’m currently building a 24x40x10 pole barn, and I’m almost done framing. The poles are 4x6s, spaced 8’ OC on sides, and then there’s two towards the middle on each end. My current concern is that when I get on the roof, I can sway it around a little bit. The whole roof assembly is rock solid, I’m specifically talking about like the top of the poles bending a little. I’m not sure if there’s any additional bracing I can add, or if the metal siding might sure some things up.

If its not a big deal, take some cabling and make an X in one of your bays, see if that stiffens it up.

The roof will help, its going to sorta act like a diaphram, so loads can be shared.

 

[Jeeper89]

My 40x60x16 was really bad until I put Y bracing from the headers to the posts and some longer 2x6's flat from the top of one post to the bottom of the next on the corners. Then I finished up the sidewall steel and it's rock solid now.
View media item 83077

 

[SickSpeedMonte]

The sheathing acts as a shear plate. The framing's main structural purpose is to handle the vertical load. I would brace around large door openings, but I think the rest is overkill.

 

[NUTTSGT]

Do you have all of the wall and roof purlins on?

Also they should be double-nailed in my opinion (2 nails wherever it crosses another framing member) as otherwise there's a perfect pivot point for a parallelogram.

The roof metal will add a lot of strength in shear, especially if screwed on the flats. Ideally the purlin nails should also be shot at an angle to improve pull out resistance, but this wouldn't increase stiffness.

This would be my question also. Any purlins/girts/metal sheets installed ?

 

[randydupree]

I have 2 24x48 x 14 open pole barns down on the beach 10 miles from Mexico Beach,i X braced the poles with flatbar steel to prevent racking.
When hurricane michael came through he wiped out all the houses around me.
My pole barns survived.

100 miles north my bus barn,50x40x18 was x braced the same way,i bolted the coallar ties with big bolts and washers,everything is screwed and bolted,it has steel sides.
The hurricane came through here as well,no damage to the building i built,but another building i own right beside it lost 9000 sf of roof.
I lost many trees at that same location.

Screws and bolts and hurricane straps don't cost a lot of money,and it saved both of my buildings,both took a direct hit with a Cat 5 hurricane.

 

[mike758]

The roof metal will add a lot of strength in shear, especially if screwed on the flats. Ideally the purlin nails should also be shot at an angle to improve pull out resistance, but this wouldn't increase stiffness.

This would be my question also. Any purlins/girts/metal sheets installed ?

No metal installed yet. All purlins are in and double nailed. No metal installed yet. I know the metal siding is a big part of the strength of the building, but I just didn’t know if being able to shake the framed roof was normal

 

[383]

You should have temporary diagonal bracing on each wall, it can be removed after the siding is installed.

 

[nadogail]

Too much shear panel should be just enough.

 

[Marctrees]

Mike - Nobody has yet talked about the importance of proper bracing the trusses.

CONTACT your truss mfgr and they will give you specific bracing instructions.

The design and on site installation of the bracing is just as important as the truss engineering.

Marc

 

[Marctrees]

Generic info -

https://www.pole-barn.info/roof-truss-bracing.html

https://www.finehomebuilding.com/2007/11/06/why-brace-some-truss-webs-but-not-all

 

[matt_i]

Mike - Nobody has yet talked about the importance of proper bracing the trusses.

CONTACT your truss mfgr and they will give you specific bracing instructions.

The design and on site installation of the bracing is just as important as the truss engineering.

It has to be listed in the engineering specifications if its part of the "engineered roof system".

For uplift you can either buy a sheetmetal bracket (Simpson, etc) or with a double top plate you can buy a long timberlok screw that penetrates both as well as the heel of the truss.

 

[Marctrees]

"For uplift you can either buy a sheetmetal bracket (Simpson, etc) or with a double top plate you can buy a long timberlok screw that penetrates both as well as the heel of the truss."

True, but a seperate issue from lumber on site in situ contractor provided and installed bracing.

Just sayin so someone not hip to this doesn't get confused.

Marc

 

[scotty95]

I just had this 24x40x10 built in michigan.