# calculations for hip on wrap around stairs on a 22,5 degree deck



## yundar dawize (May 30, 2013)

my deck has a 22.5 degree corners. i am building wrap around stairs. is there a formula for this. i usually just use a straight edge along my common jacks. i know the formula for a 90 degree.


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## jlsconstruction (Apr 26, 2011)

Are you asking how deep to cut your treads in the stringers?


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## Dirtywhiteboy (Oct 15, 2010)

He has hips and jacks:blink: he must be talkin about a roof:whistling


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## mgb (Oct 31, 2008)

double cheek cut on a hip stringer, lol doesn't sound right.

Trigonometry will give you your answer.


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## knucklehead (Mar 2, 2009)

couple strate boards and a pencil .Maybe a square and a string. what is trig?


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## Warren (Feb 19, 2005)

The rise is the same. Multiply your common run by 1.08333 and you will have the run.


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## FramingPro (Jan 31, 2010)

Like Warren stated above. Your rise is a fixed measurement, it will not change. Your variable is your run.
In my diagram i used a 10" run for the common stringer, I bisected the 157.5* angle (22.5* corner) and ran a line out to represent the centre of the hip stringer. 
As you can see the common stringer has a 10" run.. The hip stringer, since it runs at a 11.25 degree angle must have a larger run to meet the 10" riser line. 

My measurements do not jive with warrens. If i multiply 10x1.0833 it comes out as 10.833" (approx. 10 13/16")
My measurement comes out to 10 3/16"
To summarize my point. A hip stringer must have a larger run because it runs at an angle, therefore making it longer then a square common stringer.


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## Warren (Feb 19, 2005)

Nick:

Mine was flawed. It would be based on a common run of 12. The "hip" stringer run would be 13. 22 1/2 degrees is a 5/12 pitch. If you use the pythagorean theorum, you will see that 5 up and 12 over gives you a hypotenuse of 13. 

I guess you could multiply the run by 13/12 and get the result.


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## FramingPro (Jan 31, 2010)

Warren said:


> Nick:
> 
> Mine was flawed. It would be based on a common run of 12. The "hip" stringer run would be 13. 22 1/2 degrees is a 5/12 pitch. If you use the pythagorean theorum, you will see that 5 up and 12 over gives you a hypotenuse of 13.
> 
> I guess you could multiply the run by 13/12 and get the result.


I was gonna say, the calc works out for 45 corner with a 22.5* hip stringer.


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