Calculating rafter length

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  • čas přidán 19. 06. 2016
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Komentáře • 104

  • @satanandsawh2163
    @satanandsawh2163 Před rokem +2

    Thanks for your clear explanation. I needed to find this out for my DIY project. One does not have to attend carpenter's school for some years to be able to enjoy building something. Even non carpenters like to build. We do not know all the details so we need help. You were open minded and unselfish in sharing knowledge and special thanks to you for this. The world needs more people like you.

  • @charlesscott2913
    @charlesscott2913 Před 5 lety +26

    Listen, this explanation is perfect. What people aren't considering is that this is the theoretical line length. There are adjustments to be made to the stock. If you want the whole explanation take the 4 year course and spend the 8000 hrs in the trade and be a carpenter. Other wise sit back, relax and say thank you. Or hire a ticketed tradesmen. This is why trade time is expensive, because it's not as easy as watching a 9 min video.
    Thanks for the video.

    • @pegasus3862
      @pegasus3862 Před rokem

      @John Lowell right, some old school carpenters don’t like changing there ways tho

    • @TheToolnut
      @TheToolnut Před rokem

      I believe he gave a good explanation of it except for the deduction for ridge thickness. I always subtract the ridge thickness from the span and then divide by two to get my run, 👍💪🔨🇮🇪

    • @wecomeinpeace5082
      @wecomeinpeace5082 Před rokem

      ​@John Lowell Well what are you waiting for? Go get your calculator and come make 6 figures with us. See you out in the field!!

  • @cedarpoplar
    @cedarpoplar Před 2 lety +2

    I look at the numbers and I get overwhelmed. I take a few seconds to see what .88 x 16 = 14.08 means and I realize 14/16s it's 7/8s. Then I think to myself: "was that it?!" I'm drowning in a glass of water

  • @derrickwoodberry7237
    @derrickwoodberry7237 Před 3 lety +1

    Man thank you for the simplified answer.

  • @jackf498
    @jackf498 Před 4 lety +6

    the run of 14ft should also be converted to inches so the half inch extra of the sheathing can also be accounted for when calculating the line length of the rafter ...so 14x 12= 168....then add .5 ...so 168.5x 14.42= 202.48in.........=202and 7/16

    • @sc00b3y
      @sc00b3y Před 4 lety

      I was wondering about that. Thanks for clearing that up

  • @ouroboros5378
    @ouroboros5378 Před 4 lety

    Extraordinary your explanation! Thanks from chile 🇨🇱

  • @AdorableDeplorable711

    Thank you for doing multiplication the same way I was taught! Very refreshing! Thank you for helping me!

  • @MrRainbird12
    @MrRainbird12 Před 7 lety +1

    Great explanation !! Thank You !

  • @carsondinwoodie5840
    @carsondinwoodie5840 Před 4 lety +1

    Still thinking of doing part two of the rafter lesson?

  • @davidnunes299
    @davidnunes299 Před 7 lety +2

    Where is the next video, please?
    I want to bring the American culture here to Brasil.
    You're so smart and secure.
    Thank you for the sharing and dedication!!

  • @iainowsiany7424
    @iainowsiany7424 Před 3 lety

    Just what I was looking for. Thankyou

  • @alpc8539
    @alpc8539 Před 2 lety +2

    To the point and very easy to follow, instead of some complicated equations 👍

    • @UpcomingJedi
      @UpcomingJedi Před rokem

      I find it helpful he explains those numbers on the framing square. The math is simple. A^2+B^2=Sqrt(C^2). Basic algebra really.

  • @timothydore2302
    @timothydore2302 Před 6 lety +3

    Be nice if the volume of the movie could be louder so I could turn down but couldn't make volume louder

  • @gregl2249
    @gregl2249 Před rokem

    Great demonstration-wish you would have continued down the framing square to show valley and jacks

  • @jeremyfoster6942
    @jeremyfoster6942 Před 5 měsíci

    On a calculator, .42 × 16 = 6.72 round that up to 7, so that's 14 inches and 7/ 16ths for every foot of run

  • @maxenra
    @maxenra Před 6 lety

    Thank you!

  • @EDDIEGARAGE
    @EDDIEGARAGE Před 6 lety +4

    how to determine the pitch (6,12) or (4,12) or (5,12) or (3,12) and so, so why is so problematic the overhang thanks

    • @liamg1995
      @liamg1995 Před 4 lety

      To determine the pitch of an existing roof, it is possible to determine the pitch using a framing square and a level. Hold the level on the blade of the square and hold the square so the 12" mark on the intersects the roof line and the tongue is pointing down. Then adjust the square and level until the level reads level. Then read where the roof line intersect on the tongue of the square. This is the pitch of your roof.

    • @liamg1995
      @liamg1995 Před 4 lety

      To determine the pitch of an existing roof, it is possible to determine the pitch using a framing square and a level. Hold the level on the blade of the square and hold the square so the 12" mark on the intersects the roof line and the tongue is pointing down. Then adjust the square and level until the level reads level. Then read where the roof line intersect on the tongue of the square. This is the pitch of your roof.

    • @liamg1995
      @liamg1995 Před 4 lety

      The overhang is usually just added on to the end of the rafters after the birdsmouth cut as a certain number of feet and inches. It is not really necessary to have it as part of the calculation because it does not affect the length or pitch.

  • @jonathanjacobo612
    @jonathanjacobo612 Před 4 lety

    Is a 10x10 shed good for 3/12?

  • @user-hv6ov3pm3f
    @user-hv6ov3pm3f Před 5 lety +1

    Awesome. Thanks

  • @pumpkinpeanut1
    @pumpkinpeanut1 Před 5 lety +3

    Sir, when determining the length of the rafter do we have to add the thickness of the exterior siding? If I plan on adding a half inch thick siding, should I add that to my figures?

    • @baldyslapnut.
      @baldyslapnut. Před 4 lety +2

      Yes, his example assumes this since he said outside to outside. It's always overall external dimensions including finishes. What he didn't point out is deducting half the ridge thickness, but his diagram didn't include a ridge board.

  • @BillyMustang101
    @BillyMustang101 Před 6 lety +4

    So much easier with the metric system working out angles, lengths etc

  • @redsresearch
    @redsresearch Před rokem

    Don't you have to take off more then 3/4 if the slope rises above a 4?

  • @throughoureyes5160
    @throughoureyes5160 Před 3 lety

    I looked for the overhang video. Can you explain the over hang? I have a 10'X12' deck, I would like the over hang off the roof to cover 2' over all sides.

    • @FirBurger98
      @FirBurger98 Před 2 lety

      Just add 2ft to the rafter length for your total length

    • @rickescover1862
      @rickescover1862 Před 2 lety

      @@FirBurger98 correct way 14.42 x 2 = your 2' over hang

  • @robertsmithjr.5839
    @robertsmithjr.5839 Před 6 lety +5

    What about the thickness of the ridge beam????
    Also, he came up with 14.08 but then dropped the .08!!!!!!!
    Where did that go?!

    • @guitarslinger319
      @guitarslinger319 Před 5 lety +14

      .08 of a 1/16th.......if you could even see it you couldn't cut a rafter that accurate.....

    • @noblecarpentry
      @noblecarpentry Před 4 lety

      @@guitarslinger319 1/16" x 14 would be 1 1/8". Please read charles scott
      comment!

    • @guitarslinger319
      @guitarslinger319 Před 4 lety

      @@noblecarpentry you could see that...

  • @kopynd1
    @kopynd1 Před 7 lety +1

    I work in metric, but I would also work imperial

  • @mesutaltunisik815
    @mesutaltunisik815 Před 3 lety

    How is it calculated at how many degrees?

  • @joekind1
    @joekind1 Před 11 měsíci

    Trick question: what is a one half pitch common rafter. Is it 6 x 12 or 12 x 12?

  • @jorgecruz1974
    @jorgecruz1974 Před 2 lety

    Thank you for this video it's helpful for me

  • @ramosf5a
    @ramosf5a Před 5 lety

    Old school carpenter

  • @MrMaraspini
    @MrMaraspini Před 2 lety

    That was a great explanation. That totally helped me for class. dont see your over hang video.

  • @UpcomingJedi
    @UpcomingJedi Před rokem

    One thing i notice is you are not conidering a top plate at the apex to calculate the run which woul be the run minus half the thickness of the top plate which then gives the correct run. That way you have something to attach the rafters to.

    • @TheToolnut
      @TheToolnut Před rokem

      Ridge thickness needs to be allowed for, 👍🔨🇮🇪

  • @raul7317
    @raul7317 Před 4 lety +1

    slope= rise/run he say span= 28, run=14, slope=8/12, (rise/14run=8/12) we need to now the rise, rise= 14runX8/12= 9.33
    rise= 9.33 rafter= √rise²+run² , rafter=√9.33²+14² = 16.82 answer

  • @jonathanblankenship9732

    where do you get the 1/16 inches and the 7/8 at the end?

    • @chrisscott510
      @chrisscott510 Před 6 lety +1

      Jonathan Blankenship . He is trying to figure out what .88 of an inch would be on his tape measure. So he converts it into how many 1/16" is the closest to .88 the answer would be 14/16". If you count 14/16" on your tape is is the same as 7/8" .

    • @emanuelhostetler654
      @emanuelhostetler654 Před 6 lety

      Jonathan Blankenship 14 1/16 is 7/8 of a inch

  • @keithowensii7111
    @keithowensii7111 Před 2 lety

    I have a run of 15 and it will be on a 7 what is my rafter length

  • @zapatamxverm6793
    @zapatamxverm6793 Před 7 lety

    master carpinter thks

  • @herbertherbomoore415
    @herbertherbomoore415 Před 4 lety

    Where did the 16 come from; along with your answer?

    • @brandondill4234
      @brandondill4234 Před 4 lety

      When your dealing with a decimal and you want to find it on a tape measure in 16ths. You multiply the decimal by 16. This will convert the decimal to a usable 16th number on the tape measure. Here he got 14. So that's 14 (16ths), or reduced is 7/8. Really easy once you do a few times.

  • @RedNeckBiker109
    @RedNeckBiker109 Před 7 lety +1

    Does your final measurement account for the ridge beam? I think that's what its called..Thanks

    • @455supreme
      @455supreme Před 7 lety +1

      Does not look like it, but this video did for me was explain the framing square. I like that, no one around to explain it. Thankfully I found a old one a few months ago in a thrift store for nothing. New framing squares do not have that info on them.

    • @twicebittenthasme5545
      @twicebittenthasme5545 Před 4 lety +2

      A lot of buildings these days are not built using a ridge beam. If it is used, half the thickness of the beam is the amount deducted from the final cut measurement of the rafter.

  • @jurnagin
    @jurnagin Před 5 lety

    Its not that complicated is it? Cant you just start with one? and figure it out by looking at it?

  • @robertogonzalez8195
    @robertogonzalez8195 Před 4 lety

    It a very interting i like it hope have more viedios

  • @MyFortressConstruction

    4:26 No overhang discussed and won't be in this video. Video then loops.

  • @guillermoisidoro4060
    @guillermoisidoro4060 Před 7 lety +1

    201.88 inches? From where? ; it must be....20. 18" or 20 1/8" isn't it?

    • @rapunzeleh546
      @rapunzeleh546 Před 6 lety +3

      just the hypotenuse of a right angle triangle... the length of the 'rafter' is the square root of the sum of the squares of the other two sides. so if it's 2 feet wide and 1 ft high, it's 2x2+ 1x1 = 5... the square of 5 is 2.236...

  • @guitarslinger319
    @guitarslinger319 Před 5 lety +1

    Good grief folks..I'm dumb as shit....and I got it....

  • @codyreagan5754
    @codyreagan5754 Před 4 lety +1

    Did this video play twice or is it just me

    • @ICar-co2kx
      @ICar-co2kx Před 4 měsíci

      I was wondering the same thing

  • @legendaryskulls337
    @legendaryskulls337 Před 6 lety

    Where in the hell did u get the 7/8 from

    • @josebaez7780
      @josebaez7780 Před 6 lety +2

      14/16=0.875
      7/8=0.875

    • @rapunzeleh546
      @rapunzeleh546 Před 6 lety +3

      when he calculated the .88 into 16th of an inch he got 14/16... when you divide both 14 and 16 by 2, you get 7/8... same thing. like saying 3/4 is actually 6/8ths

  • @jasonnester9514
    @jasonnester9514 Před 3 lety +1

    I just use Pythag therom.

  • @gbeverly0002
    @gbeverly0002 Před 4 lety

    How would you figure out the diagonal without the framing square? Pythagorean theorem?

    • @felixcarrillo973
      @felixcarrillo973 Před 4 lety

      Jarlborg1984 yup

    • @CurmudgeonExtraordinaire
      @CurmudgeonExtraordinaire Před 3 lety

      Basic geometry (or trigonometry, depending upon which way you calculate it)... You could calculate the angle taking the arctan of "rise divided by run" (i.e. opposite over adjacent). Then solve for the hypotenuse by way of:
      cos(θ) = adjacent / hypotenuse
      hypotenuse = adjacent / cos(θ)
      rafter = 14 / cos(arctan(rise/run))
      rafter = 16.825906 ft
      Or you could do the following:
      8/12 = total rise / total run
      -> total rise = 8 * total run / 12
      -> total rise = 8 * 14 / 12
      -> total rise = 9.33333
      rafter = sqrt(total run * total run + total rise * total rise)
      -> rafter = sqrt(14 * 14 + 9.33333 * 9.33333)
      -> rafter = sqrt(196 + 87.11111)
      -> rafter = sqrt(283.11111)
      -> rafter = 16.825906 ft = 16' 13.2145/16"
      Which way you calculate it depends upon what sort of pocket calculator (or calculator app on your phone) you have...

  • @freedomfighter835
    @freedomfighter835 Před měsícem

    Very well explain!

  • @guitarslinger319
    @guitarslinger319 Před 5 lety +2

    Sounds like alot of folks have a problem for every solution.....

    • @REVerbtalk
      @REVerbtalk Před 5 lety +3

      Welcome to 2019 where if they can't catch it in 9 minutes, they are lost. This is why I ordered a framing square reference bible, square as well as watch a crap ton of videos and been thinking about asking to work along side a roofing contractor on roofing jobs they have whether they teach me to cut them or simply shut the fuck up and just watch. People today have gotten lazy.

  • @mtrotts5578
    @mtrotts5578 Před 7 lety +1

    but how do you decide if it is a 6 over 12 or 8 over 12 that confuses me?

    • @charlesle9964
      @charlesle9964 Před 7 lety

      Marcichlids !!!!!!!! Revo
      Koitom

    • @johnprice1105
      @johnprice1105 Před 7 lety

      Marcichlids !!!!!!!!

    • @lynardburt5992
      @lynardburt5992 Před 7 lety +2

      12 is the width and the 8 is the rise (UP) so for every 12 inches it rises 8 inches. The math is to figure the rafters length and to help where the birds-mouth would be and this would fit from the center beam to the wall headers (Top of wall) I hope this helps your question

    • @Scott.Farkus
      @Scott.Farkus Před 6 lety

      He didn't allow for 1/2 the ridge board width. That's the first thing I noticed, and I get a wonky number when I do it his way. Even if I subtract the 3/4" it still comes out too long. I did the same rafter layouts on CAD and got a different number. CAD doesn't lie, it's accurate to 8 decimal places.

    • @baldyslapnut.
      @baldyslapnut. Před 4 lety +2

      @@Scott.Farkus fine, but no carpenter needs to work to that degree of precision. Lots of timber framed buildings pre-date CAD. They look fine to me. Tapes and squares require no electricity.

  • @kopynd1
    @kopynd1 Před 7 lety

    also what if the run is 14' 4"

    • @felixcarrillo973
      @felixcarrillo973 Před 4 lety

      trevor francis in this case, since 4” is 1/3 of 12” you add 1/3 of 14.42, that’s 4.8 so 14.42 times 14 + 4.8

    • @johnpogany2444
      @johnpogany2444 Před 3 lety

      You can’t build the roof then lol

  • @albertoviurcos4774
    @albertoviurcos4774 Před 5 lety +1

    Real good explanation

  • @racsozerep8671
    @racsozerep8671 Před 5 lety

    yeah what happened to the other 7/8 ... his answer looks to be 14/16 but he said . 201 and 7/8 what he do with the other half ...smh confusing

    • @jroymich
      @jroymich Před 5 lety +1

      count out 14- 1/16 inch marks on tape rule it is same as 7/8 inch

    • @DONNAB555
      @DONNAB555 Před 5 lety +1

      Racso Zerep 14/16 is the same as 7/8ths. Which is the way it would be communicated.

    • @captain757747
      @captain757747 Před 5 lety

      the easiest way is to get a little book that is available. You look up the rise and the span of the building and it will give you the angle of the ridge beam cut and length from ridge bean to the seat cut.

    • @baldyslapnut.
      @baldyslapnut. Před 4 lety

      If you cannot simplify fractions or read and convert them on a tape measure, probably best to get a professional.

  • @jasonnester9514
    @jasonnester9514 Před 3 lety

    This was done to complicated much easier way

  • @legendaryskulls337
    @legendaryskulls337 Před 6 lety

    He don't know

  • @riskitallcrypto99
    @riskitallcrypto99 Před 2 lety

    5968 not 5768

  • @riskitallcrypto99
    @riskitallcrypto99 Před 2 lety

    Omg 1508

  • @CurmudgeonExtraordinaire

    Seems like you are making it overly complicated by using a framing square. It's simple geometry and anyone with a high school education should be able to figure it out. Well, at least back in my day, high schools taught geometry...

  • @raul7317
    @raul7317 Před 4 lety

    it is worng

  • @1993xavier
    @1993xavier Před 2 lety

    sooooooooooooooo confused