How To Cut Perfect Rafters

This video is dedicated to learn how you can cut perfect rafters everytime without needing to measure or guess. Cutting rafters doesn't have to be difficult with the use of simple math, and while I am sure there is an easier way out there, this method of cutting my rafters has worked well. Let me know what you guys think in the comments below. I realize post frame style rafters are a little different than a stick frame rafter, but this video will help anyone looking to cut a rafter if they just learn the simple math.
Martinez Tools
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[@garrettscott4094]

I need you to know, that I am just a DIY guy who builds for himself and his wife. The tips and practices that you share make my own projects go better, and faster. I really enjoy all of you videos. Thanks!

[@Mayhem-Mechanics]

Great video, one thing I want to point out: all roof pitches in the US are measured out of 12in. A 4/12 pitch is a 4in rise every 12 inches. This also is useful because you can use the pitch as a quick way to find the rise with the run. In this case, the run is 9ft, and since 4/12 is actually 1/3 if you reduce the fraction, you multiply the run by 1/3 and that gets you the rise. If you have a run of 9ft you have a rise of 3ft because 3 is 4/12 of nine. If you have a 6/12 pitch, and a run of 9ft, the rise becomes 4.5ft, because 6/12 reduced is 1/2. 1/2 multiplied by 9 is 4.5ft.

[@NoName-ml5yk]

Someone was paying attention in math. :)

[@KingHarry1]

Thank you I was wondering how he came up with a three foot rise. I just starting to think it was arbitrary number haha

[@scottd2410]

4" of rise for every foot of run 4"x 9= 36" rise

[@user-vb8yf8be3l]

One point there is no such thing as a 6-12 pitch a 6'' slope is 1/2 pitch. a 8'' sope is a 1/3 pitch

[@user-vb8yf8be3l]

You almost got it right.. Pitches are fractions A 4 '' slope per ft is a 1/6th pitch . It is determined by a 24' span which would give you a4' total rise 1/6th of the span. so other pitches 5'' rise would be a 5/12th pitch.. a 8'' rise would be a 1/3 pitch

[@yugenyama-0808]

This breakdown synopsis changed a gear in my mind. I’m sort of a hands on learner. Having a consistent method to approach roof framing takes some of the intimidation out of it. If you have time for further explanation and demonstration, I bet a whole bunch of folks could make the leap into trusting themselves to pull this off. Learning how to use the two tools: speed square and framing square, in multiple scenarios, would help us learn a confident approach. Thanks for the time you take explaining, the drawings, math, the practical cuts.

[@robertruff-hd3yw]

This video is well done. When I was young in the trades an older Master Carpenter told me that carpentry was just common sense. That is what you explained in this video. I was also told, "the mark of a good carpenter is no mark at all, make it look like it grew there." You showed the rafter grow from the side of that building.

[@Eric-_-23]

I just want to say that this might be one of the first video's I've ever commented on, but I've watched darn near all of yours. I'm just clearing the ground to build my own post frame house next door to you in Indiana and your videos have given me so much more confidence to do so! Thanks for all your tips and tricks! Keep them coming!

[@wirenut003]

good luck with the build

[@johnhunter273]

Dude! The way you explain math is spot on. I love using the math to verify dimensions. Drives my wife and kids crazy😂. Great video!

[@RRBuildings]

Thanks

[@eduardocastaneda2903]

Where did you get the pitch?.. Or, how do you get the pitch?

[@justinh7657]

Hey Kyle just want to say thank you- this was so helpful!!!

[@clayton1379]

You made the carpenters calculator so easy!!! I build metal buildings!! I've been doing it almost a decade and owned my own business for 3 years, and you just made my life so much easier!! Thank you!!!

[@chrisarksey]

I've never built a house, def not post frame, def not with rafters... More a DIY weekend warrior with an engineering background. Just letting you know your audience! Love your work and videos like this... Maybe I'll put it to use one day, maybe not. Shout out from Canada!

[@cuttheknot4781]

Excellent job, Kyle, as always. Thank you for those who this helped.

[@kevinorr6880]

I cannot understand why concepts a not taught in school in this manner! It makes the knowledge real world and immediately applicable. I am not even a builder and I find these videos fascinating and entertaining. When I was young and was shown the numbers in the side of a framing square, my life changed. Thank you very much for your videos and for your talent of instruction.

[@chillywilly7454]

I can’t get enough of your math content… keep it up!

[@Ty1on3twelve]

Excellent, Excellent, Excellent. Kyle you keep nailing it big time on the content you produce and share with all of us. I'm a fan. Here is one suggestion, maybe you can add a rafter with an overhang so a bird mouth would have to be cut into the rafter. It would be nice to illustrate the math behind and the actual cut of a bird mouth. Plus I enjoy the tutorial on the use of the Construction Master 5 software.

[@RRBuildings]

Sure

[@user-vb8yf8be3l]

There is no math cutting a birds mouth... Here is how say the rafter is a 2/6. you can use a scrap to make a pattern take one about 24'' lay it flat so the part on the left is the ridge and to the right would be the birds mouth. say the roof is 6'' rise... lay a square on the material with the edge off the board put the 6'' and 12'' so you can draw a line on the 6'' giving you a plumb cut now if you wall plate is 3 1/2 then take a small 2.4 scap and slide it down the plumb line until it first touches the bottom of the board... A 2x4 is about the biggest birds mouth you can use because it would weaken the heel off the rafter if you want a 2'' birds mouth rip a small piecd 2'' and use that

[@wilsonspeedshop]

Great video! So informative! Never done it before, but hope to apply the math to many more things I build! Love the channel brotha!

[@joshuawilcox7394]

Awesome video! Easy to understand not planning on a build but I love learning new things that may help in the future.

[@nathanmrudd]

That seems so much harder than just using sine, cosine, and tangent, etc. Especially when remembering that Cosine is the x coordinate and sine is the y coordinate on a unit circle. Whatever works though, the answer is the same. 👍🏻. I guess I’d prefer not to have to remember what button calculates what angle, etc. good video. Thanks

[@thetallcarpenter]

I agree, and all you need to do is use degrees of pitch rather than rise over run and the calculation is super simple. Rafter length = run divided by Cosine of the pitch👊

[@aaronmcclain1279]

I agree use the common rafter line on a framing square so you know the birds mouth or cheek cut. To the ridge board or wall .

[@aaronmcclain1279]

Or blue book from swason.

[@thetallcarpenter]

@@aaronmcclain1279 😎👍

[@andrewhammock8235]

What is the point of the rafter on top of the joist cause he doesn't know how to cut the bird mouth or what

[@bry2k]

I vote yes for the epic 3 1/2 hour super in-depth every single little detail video. I've learned a lot from you and I really enjoy it when you go into the details.

[@stefboulas]

thank you for doing these videos. EXTREMELY HELPFUL!

[@matthewentwistle1584]

Such a solid video mate, super clear explanation of something that quickly becomes a game changer when you are building on a productions scale. Always worth the couple extra minutes of lay out and math to ensure everything is high and tight. I am guilty for sure of just pulling a tape and not taking that extra 5 minutes. Thank you

[@garyhodder2784]

Great video,very useful to me and cleared up some of my confusion in my projects.Thanks

[@wannago2moab]

I learned so much in this video and that says a lot. Usually this stuff doesn’t “click” with me and I’ll spend hours on my calculator punching numbers in and magically finding my way back to where I started. I downloaded the CM Pro app and played around with it while I watched the video. That’s a game changer! Also dig the Toroe glasses. I love mine. Can’t believe how good they’ve held up for me.

[@joshtube0]

Thanks Kyle, very informative, just the right amount of explanation with the app, drawings and a great practical example to go with it!

[@lycanthrope8979]

I want to thank you for taking the time to show, in this example, what you usually speed through in your videos, and I get dizzy trying to follow what you're trying to relate. I'm not a builder, per se, though the things I have done, I've done like you said you did early on...and that is place what I want where I want and measure it. I never got into trigonometry, after doing almost 8 years of Algebra, it got boring and I lost any interest in math, so thanks for re-inspiring and explaining in a way that makes sense and is a "field application" as you said in your last video, for those of us that watch if only for entertainment value. If I was 30 years younger, I'd like to take a crack at this post framing, but alas, I'll just enjoy watching you and learning what I can. 🙂

[@FixItFrench]

Brilliant! Way to make it look easy

[@bobsundance9297]

Excellent. Well done. Great instructions. I've done this a number of times and it made perfect sense. Instead of me showing someone how to do this, I'm just going to refer them to this video.

[@Huskyresqr]

This was FREAKIN' GREAT!!!!! THANK YOU for "wasting" your time to teach us...

[@mikenicholson2548]

Kyle love this type of video. Very easy to understand. Thanks

[@Christopher-WI]

Thanks for another great video full of very useful information!

[@comingtofull-ageinchrist6736]

When you use the speed square, that 4/12 pitch transferred from the square to the rafter is going to depend on a common, hip etc; you might point that difference out on the tool for everyone in another video. I think it’s great that you’re taking the time to show people how to actually do the math instead of just guessing with measurements until you get it. I was fortunate to have a dad who was a subcontractor for residential homes since before I was a teen. Not many people had that luxury, so I think it’s great that you’re taking the time to show people!

[@Z-Bart]

I may never use this. Then again maybe I will. Knowledge is power. Thank you Kyle. And Greg. Somewhere in the background.

[@NoName-ml5yk]

Excellent video. Thank you, Kyle.

[@carbo2950]

Great tutorial.

[@pdcro1247]

This video is up there with your classic you did a while back squaring out a lot with batter boards!!!!

[@BraxxJuventa]

Thanks Kyle for the elaboration. 😁👍🏼

[@jasonwalker6002]

Yes! Please ask Mark to make more of those framing squares with the slot inside for his stair gauges!

[@user-vb8yf8be3l]

I believe you can buy them

[@jasonwalker6002]

@@user-vb8yf8be3l I don’t see them on Marks website

[@lokigames5091]

Great video, I've learned from you and your channel for a few years now, wether it's tips and tricks to tools and equipment. Thx for all of it good sir🤘🤘

[@hammertime7349]

Awesome video dude. I really like when u do videos like this. All the ways u help me understand how to apply the math is awesome.

[@RRBuildings]

Glad to hear it!

[@jim9337]

Thank you, that really helped me get it right.

[@yourRenoGuy]

Thanks for showing you touched one of the most difficult. Issues in framing. Cheers

[@mistyrichardson6041]

Not Confusing...you're great at teaching....have came a long way from you're first videos.

[@coolman8336]

Great video and explanation thanks for sharing

[@wink9970]

Nice clear explaination. Well Done teaching.

[@dansullivan2954]

That was well explained Kyle. Even l followed it.

[@dianam636]

I wish I could give this one more than one thumbs up! You gave a clear explanation. Many, many thanks.

[@kule510]

Great video! Keep them coming

[@robbjerls2252]

Awesome video really deep content I think you broke my brain 😵‍💫 Really enjoy the channel thou thanks

[@rickgalos5567]

relax, you explained it very well.

[@jameschupp2230]

Always good to know The Math. Thank you!

[@ChrisKuwait]

That was an excellent tutorial. I'll never built a rafter, but after watching this I'm sure I can haha

[@bryanlamb319]

Awesome video sir!

[@ModernMountainLiving]

We are putting up SIPs walls and trusses on our pole barn.

[@iamblaineful]

I first learned wall framing layout and then my grandfather taught me common rafters using the step-off method to get birdmouth cuts.

[@GoodwillCriminalsOfDallas]

I learned an old-school trick from my grandpa. You set a nail at the top where the rafter will go and run a string down the lower edge. He took two 1-foot sections of 2x4 with a wing nut thru one end (think of the image of scissors without handles). He set that on top of the horizontal beam and pivoted one board to line up with the diagonal string. He tightened the wing nut and had the angle to transfer to the board. It was a simple matter to do the same for the top then measure the distance between the two top points and transfer the info to the rafter and cut.

[@Ham68229]

Not really confused but, have to ask, the board in which you're fastening the rafter too, at the notched end you have, do you intend on using rafter/joist hangers? I've seen similar used like that and have seen that notch split right out over time, hence my question. Your channel is the best on YT about building/framing, have learned a lot and still learning and some parts, still confused on. Truly enjoy your videos, cheers :)

[@user-vn6hi2bi3g]

Great Job. I like that modified framing square, would buy if it was for sale at reasonable price. Good job of explaining, suggest you show how to notch and cut rafters to end of eave for lesson two of rafter show. Lesson three could be how to cut bisecting corner rafter on L shaped or hip roof. Ray Stormont

[@kencotton4645]

Very helpful!

[@steveott1884]

Very Clear. Good video. Just need a calculator like that!

[@darwinjohnson7731]

awesome video, construction master pros are amazing

[@kevinmoncada5120]

Great video you taught me something. I would have just subtracted 3 1/2 without accounting for that extra 1/4 inch of the 2x4 diagonal and messed it up. I sure woulda been scratching my head if i was lead on the site. Thanks

[@DannyBoyInMarseille]

Thanks for explaining the system. I'd do that using trigonometry and in meters, I checked and I come to the same result. Thanks for all your videos.

[@markleeks1116]

Yeah, but trig is quicker and mm are the correct units right?

[@daryldavirro4237]

Awesome video

[@markwendler735]

Your buddy could make a killing selling those framing squares, I need one

[@christophermcneil7534]

Thanks for the short cut with the Calculator. In Carpentry school we had to do it the looooooooong long way we were taught "Pythagoras Theorem - Find Hypotenuse" (you call the "Hypotenuse" the "Diagonal") we were not allowed to use a calculator. so, we had to do the square root the long way. Peace ChrisP

[@buddy734]

great video

[@ramsantos4506]

Thank you 👍👍👍👍👍

[@GoodwillCriminalsOfDallas]

I always go back to Larry Haun who was an old school master. He made things so easy to understand. He used common sense and did not hardly ever used a calculator. I would be interested in learning how to attach a roof to an existing roof. My situation is a roof like this /\ joining into a straight-pitched roof of composition shingles. My client wants the room to have a metal seam roof. I covered the rafters with cedar planks for the look on the underside. I covered that with 30# felt and taped the seams. The perimeter is fully drip-edged. I taped up the joint where the new roof meets the old but it will be a pain to install valley flashing now because of the unevenness of the composition roof.

[@tamugrad2007]

True, but Larry just eyeballed about 90% of every cut. Takes some time to develop that skill but he had it.

[@uriahwaller627]

That’s awesome

[@alk7142]

If you look on your framing square all the info you need is there.

[@wbball15]

Good stuff, Kyle. Here's your KZbin algorithm booster commentary.

[@keithwhite1241]

Great information! I'm building a post frame myself. What framing process do you use to attach the rafter to the wall? I've watched several of your videos and have never seen what framing you use for the rafters on the walls for the porches. Can you please show that in a video?

[@kaitilulia8022]

Behind the building paper, he probably has nogging in between the studs the same width as the rafter at the correct height for the rafter to fix into

[@SRG-Learn-Makers]

That calculator is magical? which operations are done when entering rise and pitch?

[@josemireni6899]

Amazing i got better knowledge about it im beginner carpenter it really helped me. Cause nobody wants to teach us at the job site.

[@craiglyons3975]

Hi, Kyle and Greg. Great videos, you gentlemen do excellent work. Keep it up. Quick question; was that an app you were using to do those calculations? If so, could I get the name of that? Thanks. Again, amazing work!

[@carolinepaltz324]

Construction Master Pro

[@TheMayflowerPilgrem]

Wish you were based in MN. Would love to work with you guys!

[@shanelarsen5867]

It's called the Pythagorean theorem, a² + b² = c². You can also use the same formula for squaring a foundation, slab etc ..

[@sbennet1447]

Enjoy your videos. What is the device you are marking with ?

[@brucebenson9651]

Kyle, you just took all the mystery out of rafter planning. Great job explaining. Math is your friend!

[@robertalexander2506]

I'm assuming you have put a so called (Ledger board?) inside behind the siding? A lot of deck roofs may have this nailed/screwed to the outside of the wall? This is the way I think I'm going to build my shed type of roof over our front porch/patio, as it's already existing? This video is very helpful indeed, thanks!

[@danclosewest3604]

More math from Kyle the better. Beats the shit outta payin attention in school math classes

[@ohhpaul7364]

I got one for you of a similar nature. I am currently working on a house with all 12/12 pitches. The framers did an okay job until they started having to cut the valley rafters that met the valley board. Wow, I have never seen such butchery of a compound angle cut as those valley rafters where they met the valley ridge board. is that still even considered a ridge if it is the main beam of the valley? the house does a 35 degree kick at the worst location; the framers could not set their saws to the incredibly steep angle, so what do you do for that? Miter saw a 2x12? hard to match the angle still. These guys used a sawzall/reciprocating saw, it appears.

[@robertlaird6746]

Thanks dude. I've always done it the old school way without a calculator. Now I'm going to have to download that app. Question; how do you keep the pocket lint from getting into your cell phone charging port?

[@RRBuildings]

Truewerk pants do not have lint

[@stoneinthefield1]

Like Jimmy Diresta’s tips and tricks, your tips also will save years of trial and error.

[@grand04gt]

Awesome video! I think what makes it confusing for people is calculating the birdsmouth

[@DanFree7]

Yes it was confusing (which is not due to the explanation) but at least I can say nice videos, interesting stuff presented by a likeable handsome guy which knows what he's talking about! ;) cheers

[@jackc70]

Please show the completed frame work before adding roofing material and shingles. Thanks for the video

[@kaitilulia8022]

Great stuff mate,,,so easy to follow....is there a chance in future you could edit in metric for us here "down under"🙂

[@hhanger1]

he's not a metric kinda guy... 🙂although, wouldn't the math calculations be exactly the same? I would imagine the construction math app he uses does both imperial and metric.

[@sergelapierre1446]

Need now to learn the next step witch is how to nail the rafter to the frame and the wall and how many nails you will use!

[@user-vb8yf8be3l]

In his examoke there would be about 18''' off nailing but this drawing is confused because only the first rafter would have this bearing unless each rafter nailed to the ceiling joist

[@iancrossley6637]

Looking for part 4 of the big build. Is it coming?

[@genefoster8936]

I think you hit the content just right. I would have opted out of a two hour video.

[@georgeking5746]

Great video Kyle cutting rafters gives me the greatest anxiety being an DIY'er, What calculator app do you use? My oldest son and his wife just bought a house and I think that app will really come in handy helping him remodel his house.

[@chriswithrow3107]

@georgeking5746 Construction Master Pro

[@jacobwhitmore243]

Is the 9' run measurement including your eave or just from the wall to the 6x6 header?

[@ethanwalker1414]

Shouldn’t the thickness of the sheathing be included in the calculation? Or too small for construction tolerance?

[@petersmith7424]

Build to mathematical perfection but respond to reality! = Carpenters perfection

[@TryASMRWithMe]

What brand is the neon green pencil sticking out of your bag?

[@hpw59]

Also you can double the 4/12 to 8/24 utilizing the full length of the square

[@RRBuildings]

not on this square...the inner dimension doesn't go all the way to 24

[@VTX1029]

The sound is pretty low on this video, just wanted to make you aware

[@Manoffire260]

No issues here

[@RolandMartinez-cz6qh]

I like your job sir... 23:20

[@ashdee-zz1ze]

Anything except the metric system 😂. Just kidding, this is super helpful stuff mate.

[@billford9863]

Outstanding! As a construction teacher, I use your videos often ✝️🙏😁

[@user-vb8yf8be3l]

Do you teach rafter cutting

[@Bulle109]

lol, I was wondering the same thing!😱😦@@user-vb8yf8be3l

[@jeffzanin5503]

Great content, audio is way too low - it looks like you were wearing a mic, was it turned on & plugged in?

[@georgesampanis4384]

What are you using for a pencil?