Hey DIYers.
I have calculated the pitch of a roof to be 0.5/12.
So a rise of 3 inches over a run of 72 inches.
I know the slope is not much, but its for a small area for animals.
How do I measure and cut the pitch into the rafters at the top and bottom?
Thank you.
Get your carpenters square out. 72 is too long so divide by three.
Put one inch at the top corner with your left hand, and put 24 inches on the top side wherever it is. With your right. Mark down from the corner at your left hand with your third hand.
>>984400
I got a third leg. Well, more like a 3rd nub. Not ALL the girls laugh at it.
>>984384
tanx=0.5/12
tan^-1(0.5/12)=x
x=~2.4 degrees
>>984400
Came here to post this, AND he got dubs. Dubs speak the truth, OP. This is what carpenter's squares are made for.
>>984400
This guy knows what's up.
>>984384
>I have calculated the pitch of a roof to be 0.5/12.
The same as (3/16")/4.5"
Measure (and mark)over from the edge of the 2x4, 4.5"
Then measure 3/16 length offset
Draw line & cut
>>984384
Personally, I think you should consider putting the rafters on top of the supports, rather than connecting them at the side. Direct load transfer will be much better than through nails or screws or whatever.
Cutting it at whatever angle you need though is pretty easy, just measure from one side the distances you need to each edge and draw a line from one to the other. Ie measure 50 inches on the top, and 49 inches on the bottom to get an angle of something or other.
>>984440
I was told there would be no math.
>>984664
Agreed. Relying on a fixing isn't as goods relying on a load baring support to carry weight.
That aside, I think this is taking a lot more thought than required. If it were for a house fine, but again the rafters would be sat on the load bearer.
When I've built shed roofs before now I've made a simple rafter frame and sat that on the building frame. Never had any issues.
>>984664
If you set it in top, you'd still be using the method outlined by >>984400, but you'll be drawing a line perpendicular to the one he outlined for you. Google bird's mouth. Not even joking, he pretty much told you exactly how to do it the right way, the first time, the quickest, with no math.
![birdsmouth[1].png](https://i.imgur.com/pUXhcxO.png "birdsmouth[1].png")
>>984384
>>984384
Use inverse tangent
>>984665
math, my dear boy, is nothing more than the lesbian sister of biology
Take speed square, Mark your degree as a pencil cut I:e long side of your (2x4, or
Just lay the roof on top and fill the gap with scraps.
>>985673
Don't listen to bodgit and scarper here.
OP, really easy way to do birdmouths with little to no maths involved.
1. lay joist on top of wall section
2. measure height of gap of (A)
3. transfer that measurement over to (B) and mark a line
4. mark horizontal line (C) parallel with top of wall to where (A) and (C) would meet
5. cut out resulting triangle
Can be done with nothing more than a tape-measure, spirit level and/or a block of wood
>>985680
Christ that's long winded.
Just fast clamp it on where you want it to finish, draw round the top of the upright, copy to all other rafters.
