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Brian Bothun
Posted: Dec 10, 2012 01:24 PM
Round metal span building measurement
Anyone have a formula for finding the true length of the building? The job is 2 hours away, i've worked there before and know the building but never meaured the large ribs if you call them that.

The type of building I am talkin about looks like a half circle and is galvanized with deep v's.

Trying to save a couple hours of drive time.

Thanks.
Circle-D
Posted: Dec 10, 2012 09:24 PM
I have found when I have measured them they are about 25% longer. A 40' building would actually be 50' if it were pulled out till the walls were flat. Best bet is to have the customer measure it and give him a ball park price. Then write the contract "by the meter". If he is off on the measures, you won't get burnt. This is generally how I do my far away work. Fuel at $4.20 a gallon, one trip is enough.

There is also a formula to figure the eliptical shaped end, you'll have to google it.
Chicago Spray Foam
Posted: Dec 10, 2012 10:45 PM
The circumference of the outer walls if it were a whole circle is (2 pi r), then divide by two for half circle LF, then multiply by wall height, then thickness. For the roof area it's (pi r²) for the entire roof area multiplied by the the roof pitch multiplier divided by 2 for the half, then multiply times thickness.

Plus Circle-D's added 25% for ribbing.

22/7 or 3.14 will get you close enough for pi if you don't have a calculator to do it.

Hope this is what you were asking for?
james keegan
Posted: Jan 20, 2013 04:16 PM
hey Brian I have a sheet that gives you the additional specs based on the size of the building. I only have it on paper, if you like bounce an email off of me and I will send you a picture of the page that you could print and use. If you still need it that is
mason
Posted: Jan 21, 2013 10:20 AM
Check out the estimating guide from SPFA. It has the formulas of all kinds of weird shapes plus tables for cubic volume and area of pipes, areas of circles, half circles, etc, also metric conversions, R value, U value calculations and much more. It is named AY 119 under technical documents,

You can access them at spray foam.org.
mason
Posted: Jan 21, 2013 10:25 AM
Sorry document is named AY 121 not AY 119. also has how to calculate corrugated metal.
Mark Mouton
Posted: Jan 21, 2013 04:25 PM
I've measured some of those,and if I remember correctly, for every 2.5' of length, add 6". I measured all the in's and out's and I believe they use a 3' piece of sheetmetal and crimp it down.
Posted: Sep 18, 2015 05:11 PM
Brian, you can measure roof pitch here

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