Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by FF, Jan 16, 2010.

1. ### FFSongster

Jan 9, 2010
Tennessee
Hi. I am trying to find out how long to cut the 2x4's on my new chicken house roof.I am cutting the ends at 45 degree angles. The house is 6' tall. It is 4' wide and 8' long. The part I am trying to find the measurment for is black and has red lines. The brown is just the frame. Any help is greatly appreciated. Any formulas anything. Thanks a whole bunch. Dusty

2. ### MahonriUrban Desert Chicken EnthusiastPremium Member

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May 14, 2008
North Phoenix
My Coop
let me see if my kid the math whiz is here.

Be right back.

Jan 9, 2010
Tennessee
Haha ok

4. ### PunkinPeepSongster

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Mar 31, 2009
SouthEast Texas
If i'm remembering my geometry correctly, then if the pitch is 45 degrees, then the peak must be 90 degrees. If the peak is a 90 degree angle, then the appropriate formula is A squared plus B squared equals C squared. I'm sorry i don't know how to actually write the formula, so i hope you get the idea.

If i'm right, then you need to find the square root of 8 feet.

5. ### ImpAll things share the same breath- Chief Seattle

Quote:I was trying figure out how to type the formula.

square root of 8 is: 2.8284271

give or take

Imp

Last edited: Jan 16, 2010
6. ### FFSongster

Jan 9, 2010
Tennessee
Hello everyone. thank you for your replys. I have tryed that twice and both times didn't come out right. That is called the pythogoream theroem. School pays off sometimes. I'm still in it though. . I really don't know what to try. You all are a heck of alot smarter than me so I will let you all figure this out. And I thought I had alot of chickens too. I really like this place it is very helpful. But this is just out of my league. I am good at angles and some stuff because I build all kinds of weird stuff but it seems the simplier stuff is a whole lot harder.. If you all can't figure it out then don't worry about it. But I do appreciate all of you that are helping so far. That means alot. Just if you want to keep those formulas coming and I will try them tomorrow. . Thanks everybody. You can post tonight but I want be on here till tomorrow at around 1. Thank you all.

7. ### b52fizzleSongster

Sep 15, 2009
Blanchard
cant cut both ends at 45 degrees, because the top of your frame is 90 degrees, had this same problem building my a frame pens, give me some time maybe i can remember how i did it, mostly trial and error and a whole lot of close enough

8. ### MarlinchaserSongster

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Oct 18, 2007
MERRY LAND
You want some overhang, or all rain will run down the side of your coop. I would cut the 45's for the peak, then figure your length to the edge, then add at least 6 inches so you have some overhang.

9. ### G Wiz RanchSongster

Jan 20, 2009
Lompoc, CA
Forget math. Take a scrap piece of plywood and cut the corner off 2ftx2ft . Attach 2 longer than needed 2x4's and make sure they are square at 90degs (essentially you are making a really large square, the tool not the shape). Hold that assembly up against the side of your coop and measure down each 2x4 until both sides are the same length were they match the profile of your side, that is how long they need to be.

10. ### dbcooper02Songster

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Apr 20, 2007
SW Washington
They are right the square of the hyptonuse is equal to the sum of the square of the other two sides. Thus the 2 foot run of your roof and the 2 foot rise make the diagonal (rafter) the square root of 8 feet, which as someone has said is 2.8 something feet.

That doesn't allow for any overhang or anything, so cut yourself a couple of pieces about 3 and a half feet long with a 45 degree cut at one end of each. Lay them on the floor in the shape of a capital A and place a 4 foot piece across them which will represent your theoretical ceiling. Now you can square it up and draw your birds-mouth cuts and rafter tails and make a pattern which you can use to cut your rafters. You won't need the exact measurement with this method, but you will come up with a very easy to use pattern to lay out all your rafters.

hth, db