[Lordssoldier]

So I am building an 8ft by 5 ft lean to shed. I have the walls up and was getting ready to install the rafters when I realized my mistake.

For the back wall I had cut the studs with an 18 degree angle so the top plate. The problem I realized is the rafters will not sit flush on the back wall top plate if I want them to connect to the front top plate. The slope is too steep.

How can I fix this issue without taking apart the walls and starting over?

 

[Missouri Bound]

Are you saying the front wall is too low?
That is what I am understanding from your description.
How much would you need to raise the front to make it work?

 

[Lordssoldier]

No. The back wall angle is to steep. The top plate is angled at 18 degrees...I can place a 2x4 on both top plates however, the it will not be flush with the rear top plate due to the angle.

 

[Missouri Bound]

OK, I will try again to understand.
On the front wall, is the angle correct?
I am not understanding why you cut the studs at an angle in the first place.
The proper way to do it is to cut the rafters to fit. A sloped top plate will provide a sliding surface. They need to be flat.

 

[Lordssoldier]

Because I was following the plans from this Website.

https://www.hometips.com/diy-how-to/leanto-shed-build.html

The difference is my shed is slightly wider. I realize now I should have just made the studs flat and not cut them at an 18 degree angle.

I’m hoping there is something I can do to fix this issue without tearing everything down and starting over.

 

[Nealtw]

Knock the top plate off and square cut the studs
We call that experience. You will not do that again.

 

[Missouri Bound]

.

I’m hoping there is something I can do to fix this issue without tearing everything down and starting over.

Other than removing the plate and re-cutting the studs there is one thing you can probably get away with only because it is such a small structure.
Go ahead and finish your assembly and cut some blocks for between the rafters to attach them to. You could also add a 2 X 4 cleat under the rafters at the back nailed to the rear wall studs. That would help tie secure the rafters.
It may be overkill but your rafters will be secured.
And that is something you could not do on anything else but a shed.....or maybe a dog house.

 

[P C D]

That design with the sloped top plate is funky, but you can still make it work. Place one rafter on the front and back plates, the way it is supposed to be, and from your description the rafter will not sit tight on the sloped plate. Mark the rafter above the plate with a pencil line parallel to the sloped plate, and cut the "seat" of the rafter along the line. The small angle you cut in the rafter's seat should correct the excessive angle in the plate.

 

[Missouri Bound]

That design with the sloped top plate is funky, but you can still make it work. Place one rafter on the front and back plates, the way it is supposed to be, and from your description the rafter will not sit tight on the sloped plate. Mark the rafter above the plate with a pencil line parallel to the sloped plate, and cut the "seat" of the rafter along the line. The small angle you cut in the rafter's seat should correct the excessive angle in the plate.

That is the ideal solution. But then he will have to recut the front of the rafter as well. If they are already cut he may be taking away too much from the little 2 x 4 rafter. It is worth a try.
Or just get some 2 X 6's and then it will be beefy enough and have room for the cuts. With sheathing and asphalt shingles, 2 X 6's may be the way to go anyway.

 

[Photobug]

Knock the top plate off and square cut the studs
We call that experience. You will not do that again.

Nope, he will find another mistake to make next time, I always do.