Need help on trusses 9' on center or 4' on center for pole barn

[Cedar Point]

Should I go with a truss span of 9' or 4' span? Every company says different things.

 

[Fossil Farm]

Depends on snow load, wind load, roof weight, etc. Around Lake Erie and what I have seen, if the price is not too much more, depending on the size of the structure, I would go 2 foot on center. One barn we have is 4 foot on center and the house addition is 2 foot on center. Should have gone with 16 inches on center for the house for a more rigid roof frame. The additional trusses on the barn would not have been much more, and 2 foot or 16 inches on center would have been nice. Especially with the quality of wood available for trusses these days and the common use of 7/16 OSB for a shingle roof on many smaller barns.

 

[KennyG]

I never quite understood 9 feet since it's an odd number. I think the choice is between 8 feet and 4 feet. Either works. 8 feet will be cheapest. If you ever intend on insulating and installing a ceiling, go 4 feet. Liner panel can span 4 feet but not 8.

 

[Cedar Point]

Should I go with a truss span of 9' or 4' span? Every company says different things.

Thanks - 40x64 14' tall metal roof. Posts or laminated beams?

 

[GManBart]

Thanks - 40x64 14' tall metal roof. Posts or laminated beams?

Are you putting the posts/beams in the ground (set in concrete, of course) or something else (posts on top of concrete pillars, foundation) etc?

 

[BHD]

the truss can be designed to carry the same load either spacing, basically the spacing would have to deal with the purlins, used, and the size of them to carry the loads, so if cost is the issue figure both roof systems to make your decision,

some may also consider the ease of putting up ceiling materials, if desired,

I like to see some closer spacing my self, (OK it seems like if you have wide spacing and failure would occur disaster happens, but on closer spacing one can fail and the others help support until repair can be accomplished many times),

My two cents,

 

[Cedar Point]

Don't you have to lay a purlin on its edge on a 9' application. How would you get a good grip on your metal roof...?

 

[KennyG]

Don't you have to lay a purlin on its edge on a 9' application. How would you get a good grip on your metal roof...?

Yes, roof purlin on edge for 8 or 9 foot spacing, flat for 4 foot spacing. Supports the roof fine either way but you have less of a "target" for the screws if they are vertical.

 

[duke7595]

Should I go with a truss span of 9' or 4' span? Every company says different things.

For what it's worth I would not go less than 4' O.C. especially with the 14' walls, think in the long term. Good luck.

 

[RickB]

If the snow and wind load ratings compare favorably, it doesn't matter. Pole barns are not 200 year structures no matter how much lumber is used.