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View Full Version : Structural integrity of pole barns, or 75MPH winds!



Calvincrowe
Jan. 19, 2009, 01:19 AM
We are experiencing a "wind storm" currently, with sustained winds of 40 to 50 and gusts of (I'm not exaggerating) 75mph!! So, my very serious question is this: how does one know the structural integrity of a barn can withstand these conditions? Our pole barn (40 x 60, 6 x 6 post construction, metal siding-pretty standard) is 10+ years old, in good condition. But.. how do I know that? Am I freaking out over nothing? I've lived in this location for 5 years now, and am no stranger to the famous "Gorge Winds", but honestly folks, this is extreme. My dog just got rolled by it, and I barely could walk against it. This is our second day of it and our power was out earlier for several hours. Our house is 36 years old, and seems to do just fine (well, it makes a whole new set of noises at this wind speed...but nothing has flown off so far!)

Granted, it was gorgeous today--bright sun, temps in the mid 40's (but that wind chill--yikes!), and the Columbia was foaming white caps, and spindrift was floating like fog along it...stunning images. But, I'm worried about the horses in the barn.

MikeP
Jan. 19, 2009, 01:37 AM
Pole barns generally fare very well here in hurricane country. Of course, that depends somewhat on the craftsmanship of the individual builder, but a good, properly built pole barn is very tough.

Bluey
Jan. 19, 2009, 02:32 AM
Well, those kinds of winds have torn our cattle sheds of similar construction several times now.

We went along and tied the rafters better to each other with #9 wire and it held them together until last year, when we had winds over 80 mh.
That did them in the day before Memorial Day.
We were picking up pieces one mile away.
We may have had a small tornado, as it also unscrewed the shade of the overhead lamp and the chimney cap.:rolleyes:

Now every new shed is made with metal framing and heavier gauge siding, no more wood, althought that won't hold to tornadoes, nothing will.
All our old metal buildings and sheds are still holding after over 50 years.:yes:

Sure hope yours holds up.

shakeytails
Jan. 19, 2009, 03:55 AM
I wondered the same thing this past fall when we had massive wind from one of the hurricanes. DH had to move the horse trailer b/c it looked like it could be toppled- thankfully it was hooked to the truck so that gave it more stability. I thought about looking for the specs on the trusses (we built it ourselves so we have all that stuff) but didn't. I'm pretty sure they're not designed to handle sustained tropical winds, but the barn was just fine. The skylights rattled just a bit, but everything was fine. Our metal is screwed on with long screws, not nails, and it didn't even think about coming loose. We did lose some siding on the old hay barn and a bunch of shingles off the old garage, but considering the condition of those buildings, it wasn't surprising.

ponygirl
Jan. 19, 2009, 07:38 AM
I have a wood shedrow pole barn. It went through 2 Category 3 hurricanes within a span of a month of each other and I live 5 miles from the ocean. I think the answer is a tough one b/c it soley depends on how it's built and direction it's facing. We built our barn ourselves but used Miami-Dade hurricane codes in doing so. I know when I was looking at acquiring a metal building for hay and tractor storage I could get them certified up to 135mph winds. The normal building/carport was good up to 95mph winds if I remember correctly.

KSAQHA
Jan. 19, 2009, 07:48 AM
We experienced 70-80mph wind gusts less than two weeks ago. The house actually shook at one point. First time I've ever been frightened in a storm - and we get quite a few storms (and occasional tornadoes) in this area.

We did lose a chimney cap off our house and our daughter's swingset was trashed, but our pole barn and indoor survived just fine.

ESG
Jan. 19, 2009, 09:31 AM
There's a tickle in the back of my brain that says you can retrofit hurricane clips on your roof trusses. I'll have to ask Mr. ESG about it, but I think you can.

We were worried about our barn during Hurricane Ike. We had minimum 90mph winds, and nothing moved. Our barn is steel pipe, set into concrete piers and slab, and metal sides and roof. Had no idea how the barn would fare in the storm, since we'd not been there through a bad one, and the structures here were built in 1974, long before hurricane codes existed. We lucked out bigtime. :yes:

Jen, how's "our" barn working out? :winkgrin:

Kate66
Jan. 19, 2009, 01:43 PM
You can put hurricane clips on. They are dead easy and tie the roof trusses to the verticals. Just little metal twisty things that look very useless that you nail in.

MSP
Jan. 19, 2009, 03:39 PM
I have a modified pole barn and it has done well in tornado producing storms with high winds. The weakest part are my doors and I had to brace them with 2x4s during Katrina. I went out to check on the barn during the storm and my doors were inverted and the piece that over laps had snapped off on one door so I quickly braced them all and had no further damage.

Pole barns built correctly are very sturdy and wind resistant.

cyndi
Jan. 19, 2009, 04:05 PM
I am 25 miles from Galveston and we got a direct hit from hurricane Ike in September. We had CAT 2 hurricane force winds for 12 hours nonstop. We were on the 'eye wall' so did not even get the 'eye' and the lull it brings.

We had just had a metal run-in shed installed the year before - wood frame with metal siding/roof. Our barn, (it was actually built to be a shop and we converted it to a barn) that is attached to our house via a breezeway, is 40+ years old and is metal frame with metal roof.

The new run-in shed sustained zero damage. The barn lost about 4 strips of the metal roofing. Considering it was built in the 60s, we really almost expected the lose the entire roof. (The horses were somewhere else during the hurricane.) We were pleasantly surprised with the small amount of damage. Even if the horses had been there, they would have been ok.

I would expect most pole buildings to be able to withstand what you describe unless they were just not constructed well at all.

SLW
Jan. 20, 2009, 12:48 AM
We experienced 70-80mph wind gusts less than two weeks ago. The house actually shook at one point. First time I've ever been frightened in a storm - and we get quite a few storms (and occasional tornadoes) in this area.

We did lose a chimney cap off our house and our daughter's swingset was trashed, but our pole barn and indoor survived just fine.

That was the 4:00 a.m storm Fri into Sat right??? That woke me up and like you, for the FIRST time ever I gulped. It leveled two barns south of me and one between you and I, west a few miles on 247th.

ponygirl
Jan. 20, 2009, 09:23 AM
There's a tickle in the back of my brain that says you can retrofit hurricane clips on your roof trusses. I'll have to ask Mr. ESG about it, but I think you can.
Jen, how's "our" barn working out? :winkgrin:

Barn is great :)

Yes, you can retrofit hurricane clips. My parents did this to their house.

deltawave
Jan. 20, 2009, 10:14 AM
I know the wind is 30mph+ at my barn when the metal siding starts BUZZING. It's really pretty annoying--the sound is awful--but in spite of that, and with occasional storms producing 60mph+ winds on the shores of Lake Michigan, our barn is holding up just perfectly in its 3rd winter. :)

Not sure we have hurricane clips in the barn, but we definitely do in the house, which is overengineered to the point of being indestructible (we hope!). :)

TwoFoxFarm
Jan. 20, 2009, 11:09 AM
My husband and I owned a barn-building business in S. FL. He built many pole barns (he ONLY built pole barns) that withstood all of the hurricane activity in the last few years (knock on wood). Your pole barn is only as strong and wind-resistant as the poles have been installed and the rafters / trusses are attached to the poles. As a few mentioned, if you don't have hurricane straps, you can retrofit them. There's a company called "Simpson Ties" that makes every type of strap you can imagine to accomodate your type of construction. You can find them online, or go to any Home Depot or Lowe's. You just need a good screw gun and ladder and you can install them yourself in a day. As far as the poles... The fact that you have 6'x6s is a great start. When my husband installed poles in S. FL, the building method called for re-bar stakes to first be driven through near the bottom of each post - one stake drilled through each direction. This gives the pole a way to grab the cement that's poured around it. A cement footer is first poured into the hole (which has a diameter MUCH larger than the post). It dries and then the pole is dropped onto it. Then cement is poured around it and it dries around the post and the re-bar sticking out of it. If you're really interested in knowing the structural integrity of your barn, dig a hole next to one of your posts. Look for cement. Look for re-bar sticking out of the post. We actually had a job in S. FL where we followed a well-known local builder. While we were originally hired to just do an addition, we got to talking to the owner about the hurricane codes and the integrity of her barn. She assured us that her builder had followed all of the local codes and had a permit and inspection done. My husband had a bad feeling though in looking at the general construction of the barn and upon inspection (digging a hole around the posts), he found that no concrete was used in setting the posts and she was headed for disaster in a big wind. For not much money, he "retro-fitted" the barn for wind by digging around each post, adding re-bar to each post, and pouring cement around them. He also added hurricane straps to each rafter and bolted the stringers (which hold the rafters) to the posts.
If you're losing sleep over the construction of your barn, have a local builder come and take a look. You may get different opinions on how HE would have built the barn, but be sure to tell him your specific concerns. I don't know any builder that won't give a free estimate. Best of luck to you!

cowgirljenn
Jan. 20, 2009, 11:36 AM
We lost our pole barn... to Hurricane Ike. We're maybe 20-25 miles inland, and we're not sure how strong the winds were here as we had already fled.

I actually think we may have been hit by one of the tornadoes spun off from the eyewall as the damage around here was hit or miss.

Until then, we had gone through some pretty awful winds and the barn was fine. I would rebuild one here as I think our destruction was a freak thing...