I’m currently building a flat roof extension on the back of my house. The roof line needs to have a minimum 2 degree pitch.
What is the best way to work this out?
ap.
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Replies
Isn't "flat roof pitch" a contradiction in terms?
Kinda like "military intelligence"?
Military justice is to justice what military music is to music.
Flat and level are two different things.
"Flat and level are two different things."
Gosh darn it, I was kiddin' around.
But flat and level sound purty close to me................(-:My wife keeps complaining I never listen to her...or something like that.
"Flat and level are two different things."
Not to roofers who don't use such specific terms
Well, maybe - flat is any roof less than 2/12 pitch but level is an unattainable quality because even if you built it perfectly level, snow would make it settle iun the middle and dish out to pond water, which will get deeper every year from the weight.
.
Excellence is its own reward!
All-righty, then -- so THAT explains the problem I was having with my former concrete subs!
DRC
I get 0.41904923390097276/12 pitch.
Meaning 0.41904923390097276 inches rise for every 12 inches of run makes a 2 degree angle. (hope I did it right)
Many calculators on the web to help you avoid doing the trig.
Try this one:
http://www.1728.com/trig.htm
Also, for standard pitches, this site has angles listed:
http://www.roofingpeople.com/Index.cfm?Page=PitchDeg
Best of luck
I knew there would have been some basic formula for this. Thanks for pointing me in the right direction.
ap.
I checked it in Autocad and you're dead on.Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
Just had too dust off the part of my brain that stores high school math...
My geometry teacher would smile big if he knew.
Not exactly CAD, but it works sometimes.
checked it in Autocad
DId that myself, too. But my pitch triangle routine reported it as 7/16 in 12. I had to do the math to get 0.4 in 12.
Type "units" and set your Autocad units to "Engineering" instead of "architecture" to get decimals.Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
If you are given the 2° for the pitch to figure it out on your own with a Scientific Calculator or Construction Master Calculator you can just multiply the Tangent of the Degree by 12.
Using a Construction Master Trig or a Scientific Calculator.
Tangent of 2° * 12 = .419049 or 7/16"
The pitch is 7/16:12.
For every foot of run your rise will be 7/16".
Construction Master Calculator.
Press [2] [Pitch] Twice, Returns - 27/64
Press [Conv] [1] Returns - 7/16"
Press [Inches] Twice, Returns - .419049
I have alot of books with answers but I just like to figure out how they got them.
Joe Carola