Anyone who starts a video by whipping out a framing square and stair gauge nuts learned from an old timer - a good thing! Very, very good video. I've never heard a carpenter utter the word cos, or tan, or hypotenuse on the jobsite, Ever. Thanks for keeping it real in the internet world of wikipedia experts and youtube dinks!
Great video! I came here not cutting a rafter for almost 30 years since high school shop class. I had forgot everything about using a framing square to measure and do this. You helped me a great deal. one thing I will add when doing the bird mouth cut if you will flip the board over and mark it on both sides and use the skil saw on both sides in most cases it will cut all the way thru. Yea I'm allergic to that hand saw :). thanks for the video man.
this is the best video I have seen on roofing and I have watched lots of them ,most of them over complicate which is in essence a few simple principles, pardon the pun but you have "nailed " it here. , after watching iam gonna roof a 20 by 10 extension , best way to learn is to do it , Thanks a mill
Woo! I really like the way, How to simplify the roof rafter cuts. I will give an A+. Thank you so much for sharing your knowledge with the world of construction. Jose
Thank you so much for making this video Aaron. You made it to a level where its understandable and I encourage you to make more videos . I subscribed to you so I can see more of your videos.
+DanieI Joseph While I wouldn't recommend it for a novice, one of the nice things about the little battery operated saws is that I am stronger than the kick back. however, if you can follow the line there is no kick back. After 20+ years with a circular saw, I have learned how to follow the line. There must be three points of contact on a board especially when cutting an angle and even more so when cutting a compound angle. Two points of contact to secure the board so it will not rotate with the pressure from the saw on the third point. It would be safer to clamp the board in two places and hold the saw with both hands, but honestly I have never ever ever seen a framer clamp a single rafter to cut it. If one has never used a saw two clamps is the way to go, you are right Daniel. Safety first
I just use a very simple calculation to find my rafter length. Half the span divided by cos the angle I want then equals. Example. if half the span is 2600mm and the pitch is 35 degrees. 2600 / cos 35 = 3174.013931.
remember to subtract half the width of the ridge beam form that first plumb cut. say you using a 2x10 subtract 3/4". if you temp place the ridge first you can skip that.
Thank you very much Aaron! that was a very informative video. Do you think you could do a video on some basic carpentry tools that you like/have. I know it's a crazy question to ask, but hey, it's the internet haha. Take care
Good explanation, simple, understandable, basic and the rest depends of you, I only don't like one thing many tools and I think with the Square, Tape and a Pencil would be enough .
Hi, great video, thanks. I have been struggling all day to get my cuts and angles right. I am working in metric / cm, do you need to account for the ridge beam at all or can you just ignore that bit and do your a (horizontal) ignoring that and b (vertical). I have measured my a and b and got my c measurement, ignoring the ridge beam, but this may be where I am going wrong? Following this tutorial, I have got closer than anything I have done all day, but the angle of c on to the ridge beam is wrong by a few degrees. The seat is pretty good. Thanks in advance.
the calculations are the same you just need to buy a framing square that uses cm the conversion is done already for you on it find the distance of the building from there you can get all the calculations you need
I got the basics of it, you explained it very well, but Im stil confused on how to get the height of the ridge board, Im building a 16x16' cabin with a 12/12 roof. say my ridge rafter is 8" thick. how high would it be after removing the ridge rafter and compensating for the pockets
+don johnson The horizontal part of the square tells you the width of the wall and the vertical part of the square tells you the height just add up the steps of the square, that is the total height of the triangle from the bottom of the top plate on the wall (the birds mouth line) to the top of the ridge. Now subtract the height of the ridge board and you will know how high to set the ridge. 16 x16 is a good opportunity to build a hip roof that is a perfect pyramid. That is as strong a roof as you can get..., but don't let me make things more complicated than they need to be. Good luck
+Aaron Friend Far less space with a pyramid roof, I'll be utilizing what space I have for a half loft. I dont have a square to look at, at the moment but if its a 45 degree roof, just doing the math in my head, 8 foot out would be 8 foot up, minus the 8" ridge beam 7'4 for the height minus 1.5" for the top plate equals 7'2.5" yes?
+don johnson close, no need to subtract the top plate. the bottom of the birds mouth is the bottom of the triangle. so 7'4" is right provided your ridge is a true 8". If it is a 2x8 it will most likely be 7 and 1/4" so 7' 4 and 3/4" is your ridge support height.
So from there I would measure from the top of the board, C-11'2.5" (A-sq+B-sq=C-sq) minus the half of the ridge board, .75"= 11'1.75" to where I mark the 45 for the birds mouth
#Aaron Friend Hi, great video, thanks. I have been struggling all day to get my cuts and angles right. I am working in metric / cm, do you need to account for the ridge beam at all or can you just ignore that bit and do your a (horizontal) ignoring that and b (vertical). I have measured my a and b and got my c measurement, ignoring the ridge beam, but this may be where I am going wrong? Following this tutorial, I have got closer than anything I have done all day, but the angle of c on to the ridge beam is wrong by a few degrees. The seat is pretty good. Thanks in advance. @Allen Palmer
Hi, I'm doing my first project and it's a 12 X16 shed with a 3/12 (18 ") Rise but at. the end I do not subtract what I should have and finish with a Rise of 22, And not 18 as it should be. How I get the inclination of the rafter toward the gable? Im sorry my english is not very good, I hope you can understand what I'm trying to say.
you are making a triangle with a rise and a run and a hypotenuse (rafter length). the triangle's run starts at the building line or the outside face of the wall stud. So the rafter length is the hypotenuse measured from the plumb line of the birds mouth. If you are using a 2x6 rafter and it has a 4" height above the plate then that is going to make your rafter land 4" above 18 " (your rise) at the top.
Hi, im building a 4x7 shed and need some advice please. Wall frame is 2x2 and rafter timber is 3x2. Can you tell me what measurements/angle the birds mouth should be please??? Many thanks 😎
the rafter I cut in the video is for a four foot building width. If you don't have any measuring tools you can just set the ridge board to your desired height and set your rafter on top of the ridge and wall and mark the wall and ridge locations and angles. It won't be perfect, but it will be close enough. Also I recommend using lumber for the rafter that is thick enough to support your weight when you are installing the roofing material. Good luck.
Hi, thanks for replying back. Ive got a silver set square like your blue 1. If I set it at 4 common to get the 1st angle, how high do I need to mark up on that angle to make the second angle of the birdlip??? Thats what im stuck with. Like I said im using 3x2 timber for this so it should easily hold my weight 😀
4/12 is the ratio, so your building width is 4 feet. Half that is 2 feet. 2 feet or 24 inches is your run. Your rise is 8 inches 8/24 is the same ratio as 4/12. Now you have a rise and a run. You have the bottom of a right triangle (24") and the perpendicular line of the right triangle (8"). a squared + b squared = c squared is the Pythagorean theorem c is the hypotenuse or the rafter length to the building line. The building line is the point were the plum (vertical) line of the birds mouth starts. You will also need to subtract 1/2 the thickness of the ridge from the first plumb cut you make with your speed square set at the 4/12 common position. If you have a Swanson speed square the little blue book that came with it will also give you rafter lengths. Also I don't know what you mean by 2x3 but I wouldn't stand on a 2x4 with a birds mouth cut into it. Good luck.
+Aaron Friend Im even more confused now lol. Ive decided to do all angles @ 45° which looks about right 😏 what I mean by 3x2 is the timber size is 3"x2". Thanks for all your help 😎
+Aaron Friend Im even more confused now lol. Ive decided to do all angles @ 45° which looks about right 😏 what I mean by 3x2 is the timber size is 3"x2". Thanks for all your help 😎
