Has anyone ever built a 4 x 5 coop???

[michael0641]

I built a 5x4 coop and was wanting to put a regular roof on it but can't figure out length of rafters or angle to cut them...Anyone know what angle and length of rafters...It will be on the 4 foot side..If that makes sense.

 

[speckledhen]

That depends on the slope of your roof, actually, how high is the front wall compared to the back wall. I think we'd need more information than the length and width of the coop to answer that one. Also, how much overhang do you want front and back on the rafter tails? Is it a simple shed roof or gable roof?

 

[nautical_bouy]

Use simple trig,,,, if you want a 45 take 1/2 of the width times 1.414 and if you want a 22 1/2 degree angle multiply half of the span times .707. That will give you the long side of the triangle.

Your odd dimension kinda screwed you for efficient use of material.
Had you made it 3x8 you would have had 3 more square feet of space and been able to just rip a sheet of plywood then eyeball how the pitch lined up and go from there.

Hope that helps

 

[DougD]

Shed roof:

Side A squared (The difference in wall height front and back)
+
Side B squared ( The length of the span {4'?})
=
Side C squared (The length of your rafter)

Example: A (2') squared equals 4
B (4') squared equals 16
C = the square root of 20 (4+16)

This is a 45% angle making your cuts simpler.
Add for any overhang front and back. 8' Usually works well for a 4' wide building.

Gable roof

Same as above, but the span is half the width of the building.

Note:
I agree with nautical_bouy the dimensions are not very efficient,
however if you cut the 5' peices from an 8' sheet leaving a 3' piece, you can recut and use the 3'x4' pieces for the triangles on the upper ends of the building.

 

[patandchickens]

Since you are not going for efficiency in building anyhow (4x5?

), here is another method that may 'click' for you. It may sound kind of hillbilly but it actually does work just fine and many quite good craftspeople build things this way, so don't laugh. And it is math-free

1) Decide roughly how much slope you want to your roof (depends on snow load, how much rain you get, what the roof will be, uh, roofed with, etcetera).

2) Go ahead and actually build the walls, whatever appropriate heights, and raise them (tack 'em together temporarily with scrap 2x4s so they stay up.

3) Now take a piece of wood. Hold it up as if it were a rafter. Eyeball how far you think it should stick out in front and behind. Make mark using a plumbline to get tails vertical. Presto, that's how long your rafters should be

Go cut a bunch more of 'em. Since it is just a little chicken shed, I would not bother with birdsmouth cuts -- just toenail 'em in place, or if you are concerned, use those little galvanized widgies they sell for this purpose (may be called hurricane ties, may have other regional names).

Ta da. No math involved, other than making sure you gots enough wood

Pat

 

[michael0641]

I finally figured it out...I made a 22.5 angle and cut them 35 inches long....i have 1.5 in overhang on bottom of rafter and 2.5 in. on the front and back...It's only for 3 cochin bantams..

 

[nautical_bouy]

Happy to hear you got it..

Sorry I didn't think to make it simple and suggest just using the corner of a wall,,,
it's easiest to just measure the height on one side and the width on another, then measure between the two points.
Then you can throw my trig and Dougs Pythagoras's therum, right out the window.