After you understand the basics (roof pitch- rise and run, birds mouth and overhang,) you are ready to design your roof. I decided on a 6-12 roof pitch. So, for every foot of roof, you are going to be rising 6 inches. A 4 -12 roof pitch means for every foot of roof, you are rising 4 inches. etc. If you are building your own shed or building, you can decide how steep you want your roof and use this "stepping-off" method to make your rafters.
Question: If I am using a 2x6 ridge beam and 2x4 rafters will I have to adjust the cuts so that is fits right (to the top of the ridge beam)? I'm building a 12x16 with a 10/12 pitch.
@@his357 Yes, it will be longer, but if you use the step off method the length will be automatically calculated for you when you step of the number of feet in your run.
@@roncecil4620 You'll still shorten the rafter by half the thickness of the ridge board. If you're ridge is 1 1/2" thick, then you'll shorten the rafter 3/4".
I tried to keep the video short without a lot of extra theory and description. Once you make one rafter, you will "get it." I forgot to mention that you should take that first rafter and check it on your building to make sure it is right before you call all the rest of them. LOL
This is one of the best and most comprehensive videos i've seen on designing the roof for a tiny house. Thank you so very much for sharing your knowledge!!!
Best how-to rafter video I've seen short to the point. Question, HOW DO YOU FIGURE THE HEIGHT OF THE SUPPORT POST FOR THE RIDGE. THANKS AGAIN FOR THIS GREAT VIDEO
Hello Gilbert. You decide on what pitch you want for your roof first. Let's say you decide on a 6/12 pitch. That means for every foot of run you have, you will have 6" of rise in your roof. In my case, my building was 8ft wide. The ridge is right down the middle of the building. So half of 8 ft is 4ft. So I have a run of 4 feet. My roof will rise 6" X 4 or 24 inches. Similarly, lets say you want a 4/12 roof. (4 inches of rise for every foot of run. In my case 4 X 4 = 16 inches.) Let's say you have a building that is 12 ft wide and want a 3/12 roof. Take half of 12 = 6. Now mulitply that 6ft of run X 3". Your ridge beam would be up 18". Hope this helps.
Gilbert Boshell Take your rise and add the “height above plate”(the amount of board from your seat cut in the birds mouth to the top of your board) this will give you the height to set your ridge board, beam, or ledger. Line the top of the ridge board to this measurement.
You are welcome! I know what you mean .... things don't have to be complicated. I like to make videos to help people not to impress them. Ha! Thanks for the comment.
How come no one uses real math. Degrees..... protractor.... probably more accurate and useable for different purposes if we had equation. Example using modern lumber 1.5 x3.5 to replace a rafter made from pre 1960 lumber that is true 2x4, no one can explain how to do this that is not 'make a 1.5x4 using a 1.5x5.5 cut'
How would you determine the height of the ridge board my building is going to be 10x12 with the Rafer spaning the 10 making each rafter appx 6 ft plus the overhang so each rafter would be 5' 11 1/4 plus 6" for overhang rafter is 2x6 material and ridge is 2x8
Tim - my pergola is 7 ft 3 inches wide, divided by two, that would be 87 inches or half. I want to do a 4/12 gable rood pitch. Using your method of step off, how would that work with that odd number.
Again, at 7 Ft 3 Inches wide, the 1st step off is not a problem, the 2nd step off would be 1 Ft 7 1/2 Inches from the end of the 1st step off ???(added to the 1st 12 inch step off would equal half of the shed overall width) is the right?
Thanks I way understand ur way better I'm doing do my shed roof soon still not deciding on the pitch yet.. ether 5 or 4/12 pich with 6 feet run any suggestion??
Why does code prevent birds mouth cuts greater then 1/4 the thickness of the rafter? If I got a 12/12 pitch roof, to me it makes more sense to have a greater surface contact with the wall top plate and the rafter via the birdsmouth.
Sorry if this is a silly question. Did you step down four increments since they equaled 4ft and the fifth step down for overhang achieved your 5ft desired length. I am asking because I am building a 7/12 (6ft length) shed roof and your explanation is the best I've seen. I'm assuming I would do 5 step to the birdmouth and one last for my overhang. Thanks.
Hi Lindsey. My building was 8' wide. My Ridgeboard will go down the middle at 4 feet. So I stepped down 4 times and marked the birds mouth. At that point you can have the overhang stick out as far as you want. It can be one more step down or longer or shorter ...just so you mark it the same way with your square to get that same angle.//// If your building is 6' wide, your ridge board will go down the center at 3' so step down 3 times and mark your birdsmouth then step down however long you want your overhang and mark that with your square the same way.
At last I actually understand laying out a rafter. Now I can do the roof where I am extending my shed with a lot more confidence. Thank you for the post.
Your project looks like a fun project to build. On frame 6:21/6:37 it appears as if your common rafter material is a nominal 2x6 and your ridge material is also a 2x6 as I can see the bottom of the ridge plumb cut as seen below the bottom of the ridge board stock. Shouldn't the ridge board in this case be the next size up in nominal width material or a 2x8 to ensure the solid backing of each common rafter fully bearing against the ridge board? Also, you mentioned the overhang is 12 inches as measured, marked and cut; but if a facia board is to be installed shouldn't 1-1/2 inches be subtracted from the overhang dimension thus preventing the actual dimension from being 13-1/2" overhang once the facia board is installed?
4WorldPeace2 thanks for watching. The ridge board was a 2x8 which actually measures 7.5”. Plenty to nail to. The overhang was 12”. When I put the siding on, that made it about 11.5”. I then ripped the material and nailed it on the soffit. The face board was the last to go up. Worked out nice because I could get four pieces of soffit from one 4x8 sheet of the siding. If you get my drift. Very little waste of material this way. Thanks again for watching. I am really enjoying my cabin.
Thanks Tim for the basic and clear explanation. Too many other RU-vidrs go into theory trying to explain with confusion on something we will probably only do once and I've seen tons of videos.
Of the many good videos I've seen, this one was for me the best explained and easiest to follow showing the step off method. Great instructions without being superfluous.
Question You went down 4 times (4:00) because it is four ft. I get that. What if building is 57” wide? Half of that is 28.5 how do I mark it, two times? (that’s 24”) then what?
Using the square only to determine the length of the rafter was cool. This is assuming an exact building width of 8 feet and a 4 foot run. I guess if you want the birdsmouth cut to consider the sheeting, you would just move the birdsmouth position out another 1/2 inch?
Nice video one thing I’m hearing a lot is you mentioned you were using 2 x 6 and then when you went to cut the seat cut you referred to your 2 x 6 as a 5 1/2 inch now I’m in Ireland and most of our lumber is 6x2 and is 6 inches in depth I’m a bit confused
Our lumber has been downsized over the years. A 2X4 here is only 1 1/2 X 3 1/2. And our 2 X6 is 1/1/2 X5 /12.... Just take about 1/3 of whatever your lumber width is. So if you have six inches, you would go in two inches.
just found out that all the rafters on my house were cut short by about two inches. They put in a splice every other rafter about thirteen inches long and at the back of the splice they used just one nail. In some places they put a nail on each side of the splice at the back. Is this structurally sound? They are cut short on the facia end.
I framed houses for 12 years when I was younger and this is how we always did it, I always put collor ties on after. Hip roofs is where it gets fun. Thanks for educating people the right way. Don't forget crown those rafters, crown up.
I agree with the comments below, this is one of if not the best explanation of making a truss I have seen. Simple, etc. I am not going to do the ridge board down the middle but rather make stand alone trusses. will this work the same for figuring out the size of the run boards (but not cutting extra off for the ridge board)? If I am following the example you did for Gilbert B. my shed which is 12' wide by 10' deep, I would take half the 12' = 6 x my 4/12 pitch for the height of the top of my rafter at 24". Then I would step off 6 times? to create the length of the rather sides to where the birds mouth would be cut?. Then I could cut the cross piece for the truss and connect them with pieces of plywood or OSB? Thanks for any help you can provide.
You Sir are my hero ! Your video is by far the best on You Tube ! Your voice is great, you are calm and steady - you explain things perfectly. Master Teacher ! Thank you very much. I definitely subscribed !
OMG that is so funny! I'm glad I am somebody's hero! I try to explain things like I would like them explained to me. Thanks for watching and leaving the nice comment.
Birdsmouth placement has just boggled my mind without scribing and cutting and scribing and cutting until i finally end up with what I needed. You made it very clear and simple. Awesome video. Thank you for your time.
Wow, what an excellent presentation. I wish I were younger and could spend time learning from you. You are an excellent teacher. BTW my wife is from the fingerlakes area -Auburn but we live in Mebane, NC. She said she didn't realize her legs could sweat until she came to the south .
Hi William. Thank you for your kind words. I enjoy making these videos. // I don't get to the Finger Lakes very often. Now that I am retired, I stay pretty close to home in Western New York. Take care.
Thank you. I like to focus on the lesson quickly and simply ... rather than on myself. When I watch videos to learn something new, I like the person to get right to the point. I don't want long introductions or music or anything else to get in the way of the lesson. Thanks for watching.
been looking through so many videos and this is by far the easiest instructional video ive ever seen on laying out rafters. clearly all wisdom here. no math no complications. I will do this method. ty
You are welcome. I like to try to reduce everything down to its simplest form to understand it myself. Then, I teach it the same way. No need to complicate learning by introducing too many elements at once.
Hi Maria. If your roof will be 4:12 then set your square at 4 and 12 and draw a line like in the video. Make a little mark at the 12" point. Now, slide your square down to that 12" mark and draw another line. This is "step-off" #1. Now, make a mark at the 12" point, slide your square down to that point and draw another line. This is step-off line #2. The number of times you step off is determined by your "run." For example, If your building is 12 feet wide, your peak will be right in the middle at 6 feet ... you will be spanning a run of six feet so step off six times. Then your rafter will fit just right at the peak and that sixth step-off will sit right on the wall. // If your building is 8 feet wide, then your peak will be in the middle at 4 feet. You would step pff 4 times in this case. Hope this helps.
Hi Maria. I remember having all these same questions years ago! Okay, you are going to use the square to layout your rafters. If your roof is 4:12 pitch, then lay your square down on your rafter with 4 and 12 like in my video. That number 12 is where you make a mark. Then slide your square down (keeping that 4-12 angle and draw a line at that 12 mark you made. This is "step-off" number one. // (It will help if you do the process by watching the video ... stop it and do that much, then watch the video and do the next step etc. You will get it.)
In this video you did 4 steps in the step off method, because you had 4 feet. which divides nicely. what if you had something like 4 feet 6 inches. what would your last step look like?
Well Luke ... that's a good question. Normally, my buildings are based on even-numbers. No real reason to build something an odd-number in width. Lumber is sold 8-10-12-14-16 ft long. Building something an odd number width would waste a lot of lumber.
You marked the overhang down the actual length of the rafter. To get an actual 12" overhang, you need to measure perpendicular to the wall plumb line. Using the step off method, it's just one more whole step. Then when you subtract 1 1/2" for your facia board, you will have 12" of overhang when the facia in installed.
Thanks for the lesson! What confuses me is some carpenters use the 1/3 rule for the seat some make the seat the width of the top plate and other make it the width of the top plate and sheathing. Is this due to local codes , exceptions , ok or just wrong? Thanks
This is so far the best explanation of cutting roof rafters. If you don't mind, may i please ask you to help me when i soon start to cut my own rafters. I am about to cover my porch with gable roof myself. I don't know how to decide my pitch and stuff like that . Thank you in advance
I guess I would decide what would look best on your house. If it doesn't matter then consider other factors: do you live where you get a lot of snow? (steeper is better.) Overall, I like steep-pitched roofs.
No there is no too much snow . Does it mean that 6/12 is very pitched . if so then i would go maybe for 4/12. Now, i am currently watching your video over and over again to learn how to do the math and measurements to cut rafter birds mouth and maybe 12 inch overhang
