Making a bevel cut

[hermetic]

and I need your smarts. I want to put up a small lean-to. The roof will be 4', front to back. 4x4 posts, 5' high in front, 4' high in back. I drew a 1" scale plan but I cannot figure out how to measure the angle cut required at the top of the 4x4's to make the roof set flat. I have a miter saw. I guess I can just lay it all down and draw a pencil line but I'll bet some of you know exactly what angle I need to set the saw at to just zip it out. And I thank you in advance for sharing that knowledge.

Just another struggling to DIMer here.

[Wash. state Desk Jet]

1. This is just a thought

If you did a wrap, say with two by fours or two by six's ,ok so the perimeter of the shed is than framed or wrapped at the top. Wouldn't your down angle be one foot ? Why than would you need a bevel or angle cut?

Take a 2x's 4 stud and screw it or nail it at the five ft. post and to a four foot post ,than look at that angle. Or use nails and a snap line to look at it.

Just a thought.

Let me guess though 22.5 degrees?

And if you wrap it,you can add some more studs about every 16 or 18 inch's running the four foot width of the shed. Assuming your shed is four feet wide by something or something or other in length.

That way your roof will lay flat as a pancake for years!

[hermetic]

2. But flat is not what I want

I need a slope for runoff. Hence the 1 foot drop. Wish there was a built-in etch a sketch here so I could show you. But 22.5 degrees sounds like an answer so I will give that a look. Thanks.

[Kolesar]

3. A one foot drop over a four foot span is the arctangent of 1/4

Arctangent of .25 => 14 degrees

|*
|      *
| 1 ft       *
|                   *
|________________14 deg_____*
          4 ft

The opposite angle is the arctangent of 4/1 => 76 degrees. 
I don't know if this is what you were asking for.  I am not
sure that you *have to* bevel the tops of the 4x4s.  They will
be hard to set in the ground at the precise height.  

[hermetic]

4. Yes, yes, thank you

That's exactly the drawing. I have the "set in the ground" thing already worked out so this should work. It's going to take some time but once it's finished I'll post a picture.

:toast:

[Warpy]

5. Pythagoras is your friend

and high school geometry can help you figure out precise angles.

However, I like the fast and sloppy method: set corner posts cut to length, make them plumb and brace them. Run a chalk line from the outer edge of the tall upright to the inner edge of the short upright and snap it. The angle you'll get on the tall one will be the same angle you'll need on the short one. Then just use your handy Sawzall to cut them in situ.

No, they won't be airtight and you will be able to slide a dime into the joint. However, it will be stable and it will work.

[Wash. state Desk Jet]

6. look

If the posts are set at five feet and four feet and you string a wrap around the top using two by fours or what ever , you will have the drop. Frame the roof in. Than throw ply wood over the top and nail it.

I am seeing your configuration in square dimension.I mean if your going to set 4x's four posts, why not do it the right way all the way.

I am seeing the front set at five feet and the back at four feet, is that right? So wrap the top of those posts with wood ,there is your 12 inch drop.

Look at a flat roof framing system. Flat roofs are easy to do.

22.5 degrees would equal a 4/12 pitch on a pitched roof.