As interested, check my observations and perhaps my math:
Oakridge 30 Roofing Spec From Owens Corning Website
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Shingles per Square 64
Bundles per Square 3
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How could you have 64 shingles in a square, with 3 bundles per square? 64 divided by 3 = 21.33 shingles per bundle.
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I know I have not encountered 1/3 of a shingle in a bundle, are there 21 shingles in a bundle or 22?
Could it be that they put 21 in 2/3s of the bundles and 22 in every third bundle? : – )
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Also, at a specified exposure of 5 5/8″ (5.625) x the nominal length OC listed of 39″ = 219.37 square inches divided by 144 (the number of square inches in a square foot), = 1.52 square feet per shingle x 64 shingles per bundle = 97.28 square and not the 98.4 SF listed in the OC specs.
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Using an “assumed” socially and professionally accepted and promoted factor of 100 SF per square: If I were roofing large apartment complex buildings, and had need to cover 10,000 squares, I would need 1000 squares of roofing, if unexplored I would order 1000 squares only to discover that I covered only 9,840 square feet, using the OC listed 98.4 SF per “square”. I would need 260 square feet or 2.6 squares in addition to the 1000 squares I ordered. This does not take into account waste.
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If I roofed one complex a week at 10,000 square feet to cover, in 52 weeks I would be short 13,520 square feet, more than enough to do another whole 10,000 SF complex.
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At today prices, buying an additional 135.2 squares reduces expected profit if I do not account for the shortage.
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Does OC define a “square†as 98.4 SF using Oakridge 30?
Replies
If you are trying to figure it that tight and no waste tolerances, you should use an engineer to lay those shingles, not a roofer
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Thanks for all of the serious comments.
I should have mentioned that this was ...toungue in cheek. I was pursuing a matter related to shingles per bundle, length of shingle and coverage over DCI Products SmartVent, and my crazy mind went nuts on the discoveries, but one less bundle of OC 30 purchased takes my wife and out for lunch.
I have been around a long time, and all of the serious comment info was avaliable within this old crazy mind. Our dump trailer has moved lots of waste shingles off of a jobsite.
Have not re-read, but thought my post mentioned the figures did not include waste.
I did find it interesting that given my exemplary and virtual project, doing 10,000 squares week for a year, along with waste, you would need to figure a shortage of 13,520 SQ, based on OC's square definition. At today's prices, a shortage of $890,000 - $1.3M.
Some may not worry, but if I get a call tomorrow for 10,000 squares a week for a year, I am prepared. We could put the small seemingly unimportant percentage to good use. : - )
Don't sweat the details? I am currently working for one the richest men in Texas, he will tell you that coorporations pay big bonuses for crazy thinkers who discover that using 4 drops of better glue to seal a package produced 45,000 a day, instead of a whole line of cheaper glue, saves the company X$M per year.
Engineer to lay the shingles, now that is a thought. Piffin, you are getting very good at Softplan renderings. Keep up the good work.
The pessimist says: The glass is half enpty.
The optimist says: The glass is half empty.
The engineer says: You have twice as much glass as you need.
Hey, again, I am just playing...y'all have a nice weekend.
I thought engineers always figured a 50% safety factor, so the engineer should say you have exactly the right amount of glass!
My spec book read "approx" shingles per square.
The roofing spec book drives me nuts too but I just stopped thinking about it. Piffin's right...you have to factor in waste anyways...
approx is right. I have seen th ecount of shingles in a bundle vary by 2-3
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Maybe you need to treat the specified exposure as a nominal figure and adjust it to 5 3/4". Also, you really shouldn't lay the shingles tight. Leave a little room for expansion. So, if you space them 1/8", will that help?
And finally....if I'm only 2.6 square short on a 10,000 sq roof, I'm celebrating!
on a 10,000 sq. roof------easily over 200 sq. get tossed in the dumpster---so being off by 2.6 sq. is nothing.
stephen
"And finally....if I'm only 2.6 square short on a 10,000 sq roof, I'm celebrating!"
2.6 SF per square x 10,000 SQ = 26,000 SF = 260 SQ x 52 (10,000 SQ projects) = 13,520 SQ x $75.00 per SQ = a nice Christmas bonus. Ho, ho, ho. I am the one celebrating.
"Does OC define a “square†as 98.4 SF using Oakridge 30? "
According to their spec sheet...yes they do
Coverage per Square 98.4 sq. ft.
There's 22 shingles in each bundle of dimensionals. They are paired so they don't stick together.
copper p0rn