rafter angle cut

[Bernard_01]

hi folks, i will be putting a shed style roof over my small deck. the ledger board that attaches to the house is secured. the outer wall of the deck is exactly 9 feet from the house. if the top of the ledger board is at 10' 6"....and the outer wall of the deck is at 9' 6"....than what angle should i cut my rafter where it will attach to the ledger....THANKS!
-Bob

p.s. or at what numbers would i use on the framing sqaure to lay out this cut?...hmmm

[Pulpo]

I would put a plumb post where the outer wall is going to be. Measure the 9' 6" plus the width of the rafter. Run a string line from the top of the ledger board to the mark on the post. Use an angle finder against the ledger to get the angle. Then find the angle on the chop saw.

[lefty]

Your ledger is height is set. But when you get to the beam how are you going to set the beam and how are you going to attach the rafters to it?

One way would be to set the beam on top of the posts and then attach the rafters with LU hangers, so that the rafters end when they attach to the beam. That would be one angle.

Another option would be to set the rafters on top of the beam and have an overhang. That would create a totally different angle.

[Wirepuller38]

Tell us what you are using for rafters( 2x4's, 2x6's, etc).

Will you butt the rafters against the ledger and use joist hangers or will the rafter set on top of the ledger?

What about the outer wall: will you cut a birds mouth in the rafter?

All these factors affect the angle.

A ball park angle is 6 deg. 15 min.

[Bernard_01]

my rafters are 2x6 and they will sit atop the beam with a birds mouth cut. i use a protractor will quick and it looks about 17degrees without my glasses on. lol. i also will have about a 6" overhang at the outer beam...THANKS ALL.

[Wayne Mitchell]

Bernard - 17* is too much for the roof pitch you described. Your roof is pitched 1.33:12. the common rafter cut for that pitch is ......


6 deg 20 min

[Wirepuller38]

Another thought: Is there a drop in elevation in the deck floor from the house to the outer wall? If so, the angle will increase.

[GBR in WA]

"than what angle should i cut my rafter where it will attach to the ledger..."------- 5*

"p.s. or at what numbers would i use on the framing sqaure to lay out this cut?." ----
----- 1-5/16 and 12 on the square with a 3/8" deep by 3-1/2" long seat cut (bird's mouth). Page 25, fig. 27 Steel Square - Use of the Scales ... - Google Books
Be safe, Gary

[lefty]

Bernard_01,

There is no way that we can tell you what the exact angle will be because none of us are there to see exactly how you are putting it together and have no way to know all of the variables.

If the top of your ledger is 10'-6" from tje deck surface at the house, and the top of your beam is 9'-6" when you get out 10' from the ledger, and then you are using 2X6 rafters, that's onlu a 6" drop in 10', plus whatever the fall of the deck is, if any. That's not nearly enough of an angle to warrant a birdsmouth in the rafters. It's something around 5 degrees, not ANYTHING approaching 17 degrees.