Can someone confirm before I cut?

I feel like I should know the answer to this, but I want someone elses opinion before I start cutting wood up. 

I want to mount a sheet of plywood as a roof on the chicken coop, but I want it at a 45 degree angle. The posts that make up the coop are different heights, 6 feet in the front and 5 feet in the back. 

If I cut the front and back posts at the same 45 degree angle, will my plywood lay flat across them or will it come out like this?

Tinkercad isn't the best, and my skills with it aren't that great. 

Since I think it makes a difference, I'm going to cut a 4x4x10 and 4x4x12 in half THEN cut the angle instead of trying to cut the angle when I cut them in half. 

If the coop is one foot from front post to rear, a 45 degree angle will be fine, Two feet deep, 22.5 degrees, or 45 if you add a foot in height to the front posts.  4 feet, 11.25 degrees.  And so on...Or something like that.

Not enough info.  Distance between the front and back posts?  But, yeah, it's gonna come out berked if you cut them at 45.  EASY WAY:  Lay your posts out on the floor where they are supposed to be, get a yard stick or other straight edge and draw a line.

Dr. Hess said:

Not enough info.  Distance between the front and back posts?  

That's the part I forgot to take into account. I knew I needed to ask. 

The INSIDE of the posts will be 48" apart. I'm not sure, short of trying to balance a full sheet of plywood, that I have a straight edge long enough to span the gap. But I do have a chalk line somewhere. 

That's a whole other rant. I bought 6 sheets of 1/2" plywood today at a real lumber yard. They were fine laying on the pile, but in the 10 minutes it took to get them home, they were all wavey. It was cold but dry today, and they had them stored inside. I just took off the top of the pile. Surprisingly the 2x6s I bought are only slightly curved. 

What you have described is a right triangle with a 48" base, and a 12" vertical. There's no way you are going to get a 45° angle without having a 48" vertical to match the base. Don't forget to take the thickness of the posts into account either - measure from the outside edge to outside edge to get your actual base.

In reply to EastCoastMojo :

Exactly.

45° is 45°.   Your rise will be the same as your run, and your cuts on the uprights will have to be 45° to match.

Agreed, you likely don't want a 45 deg slope roof.  If it's a 4' deep coop, it'd need to be 8' tall at the front to be 4' tall in the very back.

Rather than overdesign it (ironic coming from an engineer, I'd draw the side profile in life size on one of the pieces of plywood.  That way you can eyeball it before actually committing.

So, if you are using 2x4s as your uprights, you need to add 5" to your inside dimension to get an outside dimension of 53".

Multiplying that times the square root of 2 equals 75", which is the length of your roof.

Or just use an online calculator.

Here's a handy right triangle calculator tool that might help. 

Edit - Cooter beat me to it with a different one! 

Do the pencil method (as outlined above).

Lay the front 4x4 and rear 4x4 on the ground in parallel at 48 inches apart. Use the 3rd to put on the "bottoms" perpendicular to both. You goal here is to make the bottom piece be like the ground and make a 90 degree angle between the bottom piece and both the front and the back.

Then, take your 4th 4x4 or the side of a piece of plywood or really anything large and mostly straightish and lay it from top of front 4x4 to top of rear 4x4. Use a pencil to trace the angle. The. Cut them, then use the cut ends to trace the other front and rear and cut them.

If you want to calculate the angle (which is just academic at this point), then the rise is 12 inches, the run is 56 inches (48+4+4). So you need the inverse tangent of 12/56. Or 12 degrees.

Can you run another support along side the front legs, on the inside; to attain the height required and trimmed to the proper angle to give a good nailing surface.

Curious, why 45 degrees?

rsneha said:

EastCoastMojo said:

Here's a handy right triangle calculator tool that might help. 

Edit - Cooter beat me to it with a different one! 

Also check this [awesome canoe converter]

Zombie bump, likely scammer. (I'm not clicking that).

In reply to bluej (Forum Supporter) :

it looks clean, but the poster is dirty.  So, I've taken them out, and yanked their post, and removed the link from your quote.

also, I think I have some more 'sneha's to go dig through.