Pole Barn Tips for High Wind + Humidity (Florida)

[fried1765]

A typical truss manufacture for houses and structures makes trusses that are spaced 2’ on center. A pole barn style truss would be spaced at every pole- say every 10’ and then you put rafters between. You would probably pay a bit more for standard trusses but if you plan to sheet the ceiling and or insulate it may be easier to go with typical trusses.

Check out this guy. His post method isn’t something that would be my first choice but overall he builds a good product. He does the pole barn style truss.

RR Buildings
- YouTube

Can't be a very wide pole barn if you "put rafters between" the trusses.
Longest length rafter material readily available is 18'.
Maybe max. 32' wide building?

 

[RNeumann]

Can't be a very wide pole barn if you "put rafters between" the trusses.
Longest length rafter material readily available is 18'.
Maybe max. 32' wide building?

Watch the videos I posted above- you have missed something.....but when you quote half a sentence it can happen.

 

[AllByteNoBark]

The link above took me to their Youtube page. This should be a direct link to one of the pole barn build videos mentioned above.
Building A Large Post Frame Garage Full Time-lapse Construction: NEVER BEFORE SEEN FOOTAGE - YouTube

I believe he was referring to the purlins as rafters.

 

[aczlan]

I've scoured the forum and internet and apparently I'm getting old as I can't seem to find the answers.

I'm in central florida and need to build a pole barn that I will probably close in myself doen the road. I don't need permits as I'm ag exempt.

While I don't need permits I'm trying to find a kit or some sort of specs or even friendly advice on what the minimum specs should be to provide some hurricane resistance. Online kits that I've seen don't get into details and when I ask them about Florida and wind loads the usual response is that they don't service the area. Assuming ~40'x48'x12' I'm thinking about 6x6 posts every 12' for the sides but what about sinking the posts in sandy soil and probably most importantly what about trusses and whats the best was to insulate the metal roof?

I'm also open to CFL contractor recommendations.

Thanks

Posts every 12 feet seems far apart to me, around here they go about every 8 feet, but we have to deal with snow load which isn't usually a big deal in FL.

Aaron Z

 

[chamjoe]

Posts every 12 feet seems far apart to me, around here they go about every 8 feet, but we have to deal with snow load which isn't usually a big deal in FL.

Aaron Z

Snow would be better down here as it would help keep the barns from flying away in 140mph hurricane wind gusts. As for the 12' spacing this is somewhat typical but the trusses that I've seen aren't your regular 2x4's they are 2x6's or larger when wood. The metal ones are more common but to me they are what scare me with regard to spacing but I'm lacking real specs on those data points.

 

[EddieWalker]

Trusses in an area where you don't have snow are not that complicated. The biggest thing to remember is the farther apart you put them, the bigger the purlins will have to be. I like them every 4 feet so I can use 2x4's on the flat. That means more trusses. If you are going to use shingles for the roof, you HAVE to put the trusses every 2 feet so you can deck it with OSB or Plywood. If you want to put metal over decking, the trusses have to be 2 feet apart. You can easily put your trusses every 6 feet, 8 feet or ten feet apart. Probably 12 feet too, but that's getting more in the area of when they build with metal. Off the top of my head, I believe that for 6 feet apart you have to turn the 2x4 purlin on edge, then for 8 feet you have to use 2x6's on edge, for 10 feet you use 2x8's on edge. I've never seen it done any farther then that, but would guess that using 2x10's on the edge for purlins would work for every 12 feet, but I wouldn't do it.

Back to your original question about strength, having trusses every 4 feet will give you the most strength with the best value for your dollar without any complicated engineering or construction issues.

 

[RNeumann]

The link above took me to their Youtube page. This should be a direct link to one of the pole barn build videos mentioned above.
Building A Large Post Frame Garage Full Time-lapse Construction: NEVER BEFORE SEEN FOOTAGE - YouTube

I believe he was referring to the purlins as rafters.

I was actually referring to joists or rafter ties as rafters. OP’s question was about how to insulate the building. If you build with a pole barn style truss you will need to span between the truss bottoms with some type of joist so you can insulate with batt or blown insulation.
So to be clear- perlins would go on top of the truss and support the roofing.

Back to the insulation- if you the insulation right up against the roof in “typical” pole barn fashion you run the risk or rot- especially with the humidity in Florida. That’s another reason to go away from a pole barn style truss and toward the standard style truss.

Strength, either way, isn’t an issue. The trusses and roof system are all engineered and would work fine. The issue is overall cost and time. Say you go with the pole barn truss and it saves $1500. Then two years from now you want to insulate, add lights and drywall the ceiling. The cost and time to add back in what is needed would quickly eat up the $1500.

Same goes for the posts. You can do quick and cheap- just set the wood posts in concrete. Or you can spend a bit now and use a column base as mentioned in a post above.

 

[aczlan]

Snow would be better down here as it would help keep the barns from flying away in 140mph hurricane wind gusts. As for the 12' spacing this is somewhat typical but the trusses that I've seen aren't your regular 2x4's they are 2x6's or larger when wood. The metal ones are more common but to me they are what scare me with regard to spacing but I'm lacking real specs on those data points.

Our 40' wide pole barn has 2x6 trusses, our 30' wide pole barn has 2x4 trusses.
Both have poles every 8 feet and trusses every 4 feet with 2x4 purlins nailed flat on the trusses to mount the metal roof to.

Aaron Z

 

[AllByteNoBark]

I was actually referring to joists or rafter ties as rafters. OP’s question was about how to insulate the building. If you build with a pole barn style truss you will need to span between the truss bottoms with some type of joist so you can insulate with batt or blown insulation.
So to be clear- perlins would go on top of the truss and support the roofing.

Back to the insulation- if you the insulation right up against the roof in “typical” pole barn fashion you run the risk or rot- especially with the humidity in Florida. That’s another reason to go away from a pole barn style truss and toward the standard style truss.

Strength, either way, isn’t an issue. The trusses and roof system are all engineered and would work fine. The issue is overall cost and time. Say you go with the pole barn truss and it saves $1500. Then two years from now you want to insulate, add lights and drywall the ceiling. The cost and time to add back in what is needed would quickly eat up the $1500.

Same goes for the posts. You can do quick and cheap- just set the wood posts in concrete. Or you can spend a bit now and use a column base as mentioned in a post above.

My mistake, that makes sense. Our most recent is all galvanized steel with 20 foot bays, so, totally different animal. Been a while since I was around true pole barns.

 

[RNeumann]

My mistake, that makes sense. Our most recent is all galvanized steel with 20 foot bays, so, totally different animal. Been a while since I was around true pole barns.

My haste too! I tried to make a quick response while doing something else. I wasn’t clear.....I think the OP gets it now.