Calculate Rafter Measurements

trusted expert, Anthony Lombardo. All right, we got Mr. Anthony Lombardo here to tell us all about everything that you need to figure out before you start cutting in your roof. These measurements, your rise, your run, your pitch, height above plate. We're going to break down all of that stuff and he's going to show us how he figures it out for a roof like this. So, >> so >> teach it to us. >> All right. I'm going to do my best here. So, we're dealing with a >> Hey, explain it like I don't know what I'm doing, even though I definitely do. >> Okay. So, we're dealing with a basic gable roof here, which is just an a A-frame. And uh we're trying to find that diagonal measurement of the roof rafter. So, we're dealing with a roof. There's going to be two pieces of information, two numbers that are already going to be dedicated, and that's going to be the overall width of my building and my pitch. So, I know my overall width of my building is 20 ft. And I know I'm dealing with a three pitch, which is the angle of that triangle. So, I like to use a calculator. Makes it a little bit easier. So, the first thing I'll do is I'll put in 20 feet because that's my overall width. I'm going to subtract the thickness of my ridge, which is two by material, which is inch and a half. That gives me 19 foot 10 and a half. And now I need to divide that by two because we're only dealing with half of the roof. And that gives me 9 foot 11 and a quarter. And that's considered my adjusted run. Now, once you have that number, all you have to do is hit the run button and it's stored. Then the other information that I have, I know I'm dealing with a three pitch. So I'll just hit three inch pitch. And now that's stored. And once you have those two numbers stored, just have to hit diagonal. And then that'll give me my top of my rafter plum cut to the outside of my wall plum cut. And it also will give you your rise, which is two foot five and 1316.