Slope The Pitch of a Roof

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[@lila.livinz]

Life saving video!!!. So well explained. Thank you 👏🏻👏🏻👏🏻

[@msanchez1210]

so well explained and very clear. thank you very much

[@im0nlyeli]

Brandon actually thanks a million man, I'm going into an oaks performance task and it's about this very thing. I haven't taken geometry in a while and this was an amazing refresher. I know this is two years old but it's still incredibly helpful. Thank you again for all you do. =)

[@bcraftmath]

You bet! Glad the tutorial helped. Good luck on the performance task/exam.

[@ingenieriadecostos4660]

Excelente, muy bién explicado. Gracias.

[@bcraftmath]

You're welcome!

[@BrCarla]

Great video thanks for sharing

[@joshuagonzalez7390]

Thank you sir. Helped alot.

[@bcraftmath]

You bet!

[@bajaborracho9139]

Im taking my roofers exam later this week thank you for making this make sense!

[@bcraftmath]

Good luck!

[@TheGary080]

Really knowledgeable .. thanks

[@bcraftmath]

Thanks Gary. Glad it helped.

[@georgekiadii45]

Thank you Sir. You actually end my day!

[@bcraftmath]

You're welcome.

[@brianyoung5653]

made my day.....

[@dalebesaw9699]

Excellent presentation! Good review of things learned long ago. Too long for me to remember all. Haha.

[@bcraftmath]

Thanks Dale. Glad you found it helpful.

[@mauriciosanchez3865]

Your video is awesome!!! Thank you

[@bcraftmath]

You're welcome and thanks!! I'm glad it helped.

[@Amitsa299]

You are my favorite Math teacher.

[@bcraftmath]

Why thank you! I'm glad the tut helped!

[@ThePerfectSeason1972]

Hello Brandon Craft - I have a question to ask. I am currently proposing to build a 24’Lx20’W detached garage that has to have a 5/12 roof pitch to match my existing home roof pitch. The problem I’m having is my detached garage will have 10’ tall walls versus 8’ walls in my existing home. How would I calculate the height of my roof ridge of my proposed garage I’m planning to build versus the height of my current homes roof ridge? City code here states that the detached garage roof ridge cannot be taller than the existing roof ridge of my home. It has to be subordinate, which I believe means the same or lower. There is a section of my home that runs 26.7’ wide with a 5/12 pitch roof with 8’ tall walls. Will my detached proposed garage roof beam height be taller or shorter than my existing homes roof ridge staying with a 5/12 roof pitch ? How would I calculate the differences of heights between the two buildings? Thanks ! My city code requires it before I build.

[@bcraftmath]

Hey man. Can you provide a rough sketch just to make sure I'm picturing this right? I'll definitely crunch the numbers for ya....

[@oriejohn3013]

0

[@bcraftmath]

What's up?

[@GunBlue490]

Thank you for your channel. I must advise that the three drawn examples to the right do not describe their associated names. A 12/12 pitch is easily identified with a peak having a square corner equilateral, 90° angle, where rise equals run, which would be the one you show second one down as a 8/12 pitch. As measured by my protractor, the uppermost diagram illustrates an acute angle of less than 90° at the peak; thereby having a rise greater than run, with a pitch of approximately 15/12. The bottom illustration is not a shallow 4/12 pitch. It is a familiar 7/12 pitch roof, which is slightly greater than the 6/12 minimum for snow loads in my region. I live in northern New England where a 12/12 pitch roof has been historically used on 75 percent of homes as a means of strengthening for heavy snow loads and for shedding snow, and for creating space for rooms, often combined with dormers, which would otherwise be unused attic. In contrast to your comments that are probably based on your region, steeper roof pitches up to 18/12 and greater are not at all uncommon in New England, and are frequently used in modern construction up here and in any snowy region. While modern trussed roof engineering has strengthened snow loads with lower pitches, accumulation of snow remains a concern, where steeper pitches of 8/12 and greater shed more efficiently and are less prone to "ice damming", the problem where ice melt at the eave migrates upward under shingles due to capillary action.

[@GAROmx]

Your rafter is also called a Top Chord in the roof truss world Very well explained sir 👍🏽

[@wusso7875]

A Steeple would use a 15/12 or an A frame. ?

[@chadhoffman6989]

if my existing roof is a 6:12 pitch and I'm wanting to add a room into my house and my dimensions are 15x20, what would my roof pitch be

[@roychambers3243]

Hi I use the terms rise run rake as in squared rise plus squared run equals the rake squared just seams easy to remember

[@GatorVisuals]

Very helpful , Whats the name of the program you are using also

[@bcraftmath]

Glad it helped! The program I use for writing the notes is Smart Notebook.

[@newyorklifebangladesh5947]

Thank you so so much

[@weston1830]

Thank you :)

[@bcraftmath]

+Weston Doehrman You're welcome! Glad it helped!

[@WelshRabbit]

A 15/12 or steeper pitch could be seen in Victorian and Second Empire houses, especially with garrets, turrets, and pinnacles, and generally in Gothic Revival -- oldies, but goodies, especially if one is into that sort of thing. PS: Go Tarheels. Cheers.

[@bcraftmath]

Carolina fan eh? 👍👊

[@urstudio383]

Amazing educational video. Please post more videos like this one.

[@bcraftmath]

Thanks. Glad you found the tut helpful.

[@terenceduggan6494]

Hi, I am from the UK and when we are setting out a roof we do it using the angle of the roof ie. 32deg, 35deg, 45deg. We don't use the 8/12 or 3/8 so using your way how could we do it. Thanks for any help.

[@bcraftmath]

To find the angle that you would need, you can take the arctan(rise/run). In the first picture of this video, the rise was 7 and the run was 12. The angle of the roof would be arctan(7/12) which is approximately 30 degrees.

[@bobacake998]

Have the same problem too. Have you known the answer to this?

[@Johndonvan861]

On a lean two roof/building when rising the front wall to give the roof a fall back you are also increaseing the run, and the more the rise the longer the run??

[@bcraftmath]

If the front wall that you are raising is vertical, you are increasing the rise, but essentially not changing the run, which creates more pitch.

[@julianxiong6255]

I had watched many videos and still not catching up but your finally feel I can do the math now. Thanks.

[@uptownphotography]

If you know the rise over run is there a way to calculate what the pitch of a roof is in degrees (45 degree angle, 50 degree angle, etc.) I need to do this for a recording studio project for acoustic treatment. Thanks very much. Philip

[@bcraftmath]

Absolutely. Right triangle trig.

[@stevekarch8505]

Im building a small pump house and my span is 30” and was going to do a 12/12 pitch. Would I multiply 1.25x12 to get my height of ledger board?

[@bcraftmath]

Could you provide a quick sketch so that I can accurately answer? Just drop a link to the pic here in the comments. Thanks!

[@user-em4up5xr4e]

Hi! 30”/2=15”. 15/15 pitch 15*15+15*15=450 or 21,21” rafter

[@laurieclarkson9180]

So if I do a monopitch roof/shed/lean-to/slanted (so many names for it) on a 34 ft house like yours in the example with 3/8 pitch, I would have to build 12.75' wall on top of my existing wall at the high point to achieve that? Did I do that right?

[@bcraftmath]

I could answer your question better if you provide a quick sketch of what you have in mind. Thanks!

[@bcraftmath]

It depends on how much horizontal space you want to cover. Do you have your "blueprint"? I could help you with the math, but I need more specifics than the image provided. Thanks.

[@troyladoux1953]

Is that calculator program still available? Great instructional vid.

[@bcraftmath]

I'm not sure. I now use the official app from texas instruments.... education.ti.com/en/products/computer-software/ti-smartview-ce-for-84

[@Fredits]

Thanks 👍👍👍👍

[@redd605]

Good video

[@bcraftmath]

Thanks. Glad it helped.

[@123rockstar2010]

Alternatively: Note that with 3/8, the hypotenuse to that is: Hyp = sqrt(3² + 8²)= sqrt(73) By ratio and proportion: Rafters/17 = sqrt(73)/8. Thus, Rafters = 18.15600796

[@bcraftmath]

That's right!

[@aidankeenan6883]

Don't get me wrong! I worked this out by watching ALL the youtube vids out there! And I realise that the "Old ways" are important! Using the "Step-off" method with a FRAMING SQUARE and a SPEED SQUARE from everything from a dog house to a single story home/garage etc! But my point is... If you're gonna take all that time to study all the different methods... Why not just SIMPLIFY! It shouldn't be all about the math and having to pay massive amounts of dosh for an architect or contractor... Anyone can do this with confidence with a little time spent experimenting with the drawings one can create with "Sketch-up"!

[@bcraftmath]

Aidan keenan I'm 32. The Pythagoreans are turning over in their grave at the sight of what we have at our disposal today. I just wanted to make a video to help my students out on a test in a college math class. No software or computers.... just the muscle in their head. I totally understand where you are coming from. I do a little computer graphic design and I can make a much better drawing on my mac than I can on paper. But.... I still enjoy physically erasing from time to time and I like having a little graphite on my fingers.

[@linnypsimpson5111]

Brandon Craft- Great response. I might not have answered "Aidan Keenan" with the same class, no pun intended. I was trying to explain pitch and slope to a friend of mine, with not much success, until I got on the computer and watched your video. He left here with a solid understanding and I wanted to thank you. I realized that "knowing" something and "teaching" something are two different things entirely. I know this stuff inside and out but passing it on in a way that others understand, is a very special gift and you have it. Good luck and great job, Scott

[@bcraftmath]

Glad I could help Scott.

[@joeteejoetee]

Amazing video! What is the software you are using to illustrate this? "NoteBook"? (I have a MacPC). Thank you very much!

[@bcraftmath]

Smart Notebook

[@onestartravellermarkeymark5329]

Hi, does this work with meters? How do you work out it out please? I want to build a cabin 6m wide with a ridge at 1.5 m Thanks, Mark

[@bcraftmath]

Can you provide a rough sketch? Once I have that I can provide all the necessary measurements including lengths and angles. Thanks.

[@onestartravellermarkeymark5329]

I can probably work it out as I know the run is 3m and the rise to the ridge is 1.5m so I can work out the rafter length. However, it is cutting the timber at the right angle that worries me cos I will not know whether it is a 12:8, 12: 7 or whatever, so I will not be able to use the markings on a rafter tool (triangle with all the markings) which are in feet and not in metres. Thanks, Mark

[@onestartravellermarkeymark5329]

Read below first please, but I guess the pitch must be 6/12 because the run is double the rise?

[@bcraftmath]

6/12 is the same as 1.5/3 regardless of the measurement system. You could think of the 6/12 as 6ft/12ft or 6m/12m sure the measurements are different in actual length, but they are still proportional.

[@onestartravellermarkeymark5329]

Thanks....good advice !

[@streetdei]

what is the name of the software you are using. Thanks for the tutorial

[@bcraftmath]

You're welcome. The software is Smart Notebook. It's a little over 100 bucks per year, but worth it for me since I teach. I think you can get a free version, but it will have a watermark or something like that. Check it out: education.smarttech.com/products/notebook

[@serikadil2047]

Why did you do 17x6,375 /by 2? Why did you use the hypotenuse?

[@bcraftmath]

Which part of the video?

[@SIMEONOVVASIL]

Excuse my ignorance, but who decides the roof pitch to be 3/8 or how do you determine the roof pitch?

[@bcraftmath]

In a real world application where the roof is already constructed, I would measure the rise and run of the roof. Divide the rise by the run to get the pitch.

[@EDDIEGARAGE]

very technical but!

[@bisutommy79]

HI, what pointer do you use?

[@bcraftmath]

Are you referring to the software that shows the pen on the screen? I use a Wacom tablet (hardware) and Smart Notebook (software).

[@bisutommy79]

I mean how you controll the cursor? with the mouse I coudn't draw so accurate

[@bcraftmath]

It's a wacom tablet. Take some getting used to, but once you have the hang of it, it is just like drawing on paper. You can get them at Best Buy, Amazon, etc. Some are less than $100 and some get really expensive. They work great and last a long time!

[@eichehavreberg]

what program are you using on the mac?

[@bcraftmath]

Smart Notebook

[@evangjrodriguez]

What if you don't have the 3/8 and your trying determine what the "3/8" is... For example what if it's 3/12 or 4/12... How do I calculate to determine my rise???

[@bcraftmath]

evangjrodriguez 3/12 means for every 3 inches of rise, you have 12 inches of run.... Or feet or meters or whatever unit of measurement you are using. 3/12 simplifies to 1/4 so you will probably hear of a 1/4 pitch versus a 3/12 pitch. Both are the same though. For 4/12 you can reduce to 1/3 which implies 1 unit of rise for every 3 units of run.

[@evangjrodriguez]

Brandon Craft ok and how do I figure out if it's 3/12, 4/12 or something else???

[@bcraftmath]

evangjrodriguez so you already have a roof built and you're trying to figure its pitch?

[@evangjrodriguez]

Brandon Craft yes sir...

[@bcraftmath]

Find the vertical height of your roof and divide by the horizontal distance of your roof. The vertical and horizontal distances are measured from a point that is beneath the apex of the roof and is in the same horizontal as the bottom of the roof.

[@larryp3641]

Slope is different from pitch in construction framing

[@luiscarrasco753]

where is the website you used to doodle with

[@bcraftmath]

I use Smart Notebook. I have since updated to a newer version that requires a yearly subscription. There is a free version I believe that gives you a watermark on the whiteboard or something like that. Here's the link: support.smarttech.com/software/smart-notebook/smart-notebook-17

[@joeteejoetee]

@@bcraftmath The URL is gone in 2022 - any other URL's - thanks!

[@bcraftmath]

Try googling- Smart Notebook

[@joeteejoetee]

@@bcraftmath I did, and have installed it - thanks!

[@joeteejoetee]

@@bcraftmath The users screen in your videos only said "Notebook" , so thanks for the SMART tip!

[@shawpay6987]

WOW!!!

[@bcraftmath]

Hope you found this helpful!

[@lloydmcknight]

pitch and slope are different terms meaning the same thing, angle of roof: 6:12 slope = 1/4 pitch.. 4:12 slope = 1/6th pitch, because the 'pitch' of a roof is always based on 'full pitch' 24/12!!

[@bcraftmath]

Ok. This video has received quite a bit of attention. I originally made this video many years ago to help students with a similar example they were working in a math class that I taught, which was a mathematical literacy class. This wasn't a class specifically meant for contractors or folks who are very knowledgeable when it comes to roofing. This is a general math class for college students. Students were having trouble with a similar example, so I made this video to help them solve it. Through time, I have received comments similar to this and I have also received questions about how to properly angle a roof and all of that. I am no contractor, but instead a college math instructor. I can crunch numbers and I do that well. I leave it to contractors to do the actual manual labor.

[@lloydmcknight]

@@bcraftmath all good.. my typing skill are low..(failed typing)lol. i was just pointing out the terminology, because all the video's i see about roofing the practical and theory terminology changes and can confuse apprentice carpenters. btw i'm no contractor but a Red Seal Carpenter for 20 yrs!

[@adv.nileshnikole6379]

I have 28 ft horizontal. What should be ratio?

[@bcraftmath]

How much vertical are you needing?

[@adv.nileshnikole6379]

@@bcraftmath i have 28 ft widht and 30 ft lenth

[@bcraftmath]

Take a picture of your sketch and let me see it ...

[@adv.nileshnikole6379]

@@bcraftmath our engineer is planning for 4:12 ...is it good?

[@bcraftmath]

I need more information than just the width and length.

[@sompeseth4159]

Dear how to know 3/8

[@bcraftmath]

The 3/8 is given in the word problem.

[@NobodyLikesyou.]

You forgot the 1” 1/2 in the roof. The perhaps. 3/4 both side lol

[@bcraftmath]

I'm sorry, but I'm not following what you are saying.

[@brianyoung5653]

I haven't done this kind of math for quite some time............... LoL!

[@bcraftmath]

Good refresher I hope....

[@JamesSmith-pc6bh]

I've NEVER done this kind of math. I can add 2+2 after that it all Chinese to me.

[@jetsetjoey]

The illustration of the 12:12 pitch is not accurate because a 12/12 ratio makes a 90-degree angle but the illustration depicts something more like 12/16...

[@bcraftmath]

You are right. A 12/12 pitch should make a 45 degree angle with the horizontal.

[@indredcold3191]

I'm a bit confused, I always read it 7 inch to 12 inch not feet 😐 explain please (figured feet into total inches for easier math) Plus the 15/12 pitch would be a negative pitch as is an A frame.

[@johnwaltersalas93]

They are the same. 7 inches to 12 inches vs 7 feet to 12 feet.

[@edwardcharles9764]

If this is a maths class fair enough. If it's to find the length of a rafter carpenters don't take their Mac on site with them! So for those who aren't students and want an easier life, look in the rafter tables! That's why they're there!

[@bcraftmath]

Yep, it's a math class. 😉

[@tomgodwin5912]

Why did you do square root at the end. ???. Always one peace of info left out.

[@bcraftmath]

Because that is equal to c^2 (c squared). To find "c", you need to take the square root. This is always done when using the Pythagorean Theorem.

[@tomgodwin5912]

Ok thanx

[@chucke3305]

What is 18.2 ft on a tape? 18'-2in

[@bcraftmath]

18 feet and .2 OF a foot... 20% of a foot... 0.2*12 = 2.4 inches. So, 18.2 feet is 18 feet and 2.4 inches.

[@chucke3305]

@@bcraftmath .4 is =1/4 ?

[@bcraftmath]

0.4 is not equal to 1/4. 1/4=0.25

[@chucke3305]

@@bcraftmath so I just round it off to 0 then.

[@chucke3305]

Thank you so much, you helped me out big time.

[@billk6952]

I think your span measurement is wrong ...that's not your building dimention.

[@bcraftmath]

Hey Bill. This video was originally meant to serve as just a basic math problem for some students in one of the math courses I teach.

[@walterrichardson43]

Dauwg gone it

[@aidankeenan6883]

Why are we still doing these calculations in 2017? If computers are our future and we still use calculators to do the math anyway, why not download a FREE version of SKETCH-UP and build/draw your roof with the desired dimensions/slope... Place your RIDGE BOARD up there at the calculated height... and simply (using the LINE-TOOL), draw your rafter with the desired tail and birds-mouth... Make a "copy" of it and "move" it away from the building where you can then ACCURATELY measure all the dimensions required! Seems like a no brainer to me! Using "Sketch-Up", I was able to cut ALL my rafters! The most important task then was to make bloody sure the walls where squared up to spec! They where and there were no gaps in sight!

[@bcraftmath]

+Aidan keenan that's just fine. Why so serious?

[@aidankeenan6883]

Hi Brandon! I'm so sorry if I offended you in any way, shape or form! I didn't take into consideration that your vid was to help your students and I now feel like an absolute idiot!!! Please accept my sincere apology!! My only feeble half-baked excuse is that (a) I was so excited that I had worked it out a different way and, Ironically (b) I happened to be watching your vid when the penny dropped! So I guess, it was your explanation that finally helped me work it out! Once again, my sincere apologies! Kindest regards, Aidan

[@bcraftmath]

No problem at all Aidan. I'm not offended. I was just answering your initial question as to why we are doing these calculations in 2017 (or 2016 rather since the video has a little age on it). Glad to hear the light bulb went off!

[@joshuagonzalez7390]

Taking my B license test for the 6th time. I know right.

[@bcraftmath]

Hey man.... 6th time is the charm. Let me know if you need help with other mathematics.

[@joshuagonzalez7390]

Thank you. Taking it in a week.

[@bcraftmath]

Good luck!

[@recoveringcatholic4130]

I need 72 degree slope for a pyramid and the pyramid will be like 2 ft tall

[@bcraftmath]

A pyramid with what type of base??? A square?

[@recoveringcatholic4130]

@@bcraftmath yes a square

[@bcraftmath]

And you are trying to figure out how long each side of the square base should be...?

[@bcraftmath]

@@recoveringcatholic4130 Also.... What do you want the 72 degrees to be at? The slope from the corner, or the slope from the side? Those two angles are different.

[@johnwaltersalas93]

I lost my savings for building a house without a ridgebeam.

[@bcraftmath]

Not familiar with construction, just the math... but that still sucks.

[@ebox008]

English please,,... 😉 Lol

[@bcraftmath]

😜

[@mohammadbader9997]

👍👍👍🇰🇼

[@truthisnotanopinion71]

Too many numbers, there must be a simpler way to do a simple pitched roof.

[@mendoza94]

I think you got confused.

[@billm3210]

So easy when you study and look at things simply in math terms and not contractor terms who confuse people for no reason and try to get all technical. No offense. I work with many and go back to clients and have to explain like this video with drawings not engineering that also their terms and pages upon pages of useful but really overdone info generated by software.

[@JamesSmith-pc6bh]

Glad I'm a mechanic and not a carpenter, MATH SUCKS!!!.