Truss Spacing For Metal Roof

ATS

I always thought 4' oc was standard for building pole barns using metal roofing. I was talking to a company here that builds trusses and they tell me some guys place the trusses 10' oc and use 2x6's in between. Any opinions on this?

Teetorbilt

It's all code in your area. Check with your local building dept. BTW code is not always best, just the least that you can get away with.

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joasis

It all comes down to engineering. Typically, pole barn style buildings in my area have bays (distance between trusses) of 5 feet to 12, depending on pitch, insulation, and height. If purlins are laying flat on top of the truss, 5 or 6 feet is the max on 2X4's....edge up can go to 12 feet or more. If you are building your own design, you must follow code if it applies, and you can find the info in IBC....if you build by what we would call, an engineered building package with stamped blueprints, then the seal and an approval means you can build it however the engineer says it will work.

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ATS

Thanks for the replies. Building codes are not enforced here because it is an existing structure, I'm fixing up my 1500 sf concrete block barn and the building inspector doesn't care what I do since the building is existing. Just hoping I can save some money by buying less trusses.

thom

Strange

joasis

Then it comes down to where you are, what loads will the roof have, and just how little you think you can get by with. Trusses are relatively cheap...lots of times I see people saying they want to "save" money, but when you actually look at the costs, you are talking small dollars....like the number of 2x4's saved in a 1000 sq/ft by going from 16 to 24 inch centers.....

I have built a few spec homes and used engineered wooden trusses at 8 feet on center with 2x4's as ceiling joists and purlins vertically between the top and bottom chords of the trusses. I saved some money on materials, gave it all back in labor cost, proved a point about engineering, beat the building inspector up technically by proving him to be an idiot, and said why bother?.....by the time it is all said and done and you get trusses engineered for anything besides 24 inch centers, it nearly isn't worth the headache.

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ATS

My case in point regarding the building inspector. I recently leveled (down to the foundation)and rebuilt a house I own here and of course called the building inspector prior to doing so. His response was since it's an existing structure, a permit and inspection was not required, but I could get one if I wanted. I'm not kidding, this is rural western N.Y. I love this town. I realize that 2' oc is standard for houses in this area but this will be just a storage barn and most barns I've seen around here use 4' oc trusses. I just never knew that some guys did 10' oc and was looking for some pros and cons. Thanks again for the responses.

Kgmz

Just remember you can't use the same trusses for 24", 48" or whatever centers. As the O.C spacing gets larger the trusses have to carry more weight and be built heavier. Like Joasis was saying it looks like it wil save money, but in the end it really doesn't. More expensive trusses each, more labor, etc.

For my own 3000 sq ft shop I built it conventially instead of pole building style. This way in the end it is better insulated, easier to sheetrock, etc.

keepitstraight

our neighbor just put up a pole barn w/metal roof (industrial grade, thicker than the residential stuff used here) his trusses are about 10 foot centers, but he has hangered 2X6 on two foot centers between them. basically saved having to have supporting beams between his posts. for what it's worth, we have a 65lb/sq ft snow load here, but not as bad as in the mountains where it gets around 145 lb snowload (averages 400 inches/yr at wolf creek pass.)