Rafter Calculations for a Hip Roof: Hip Rafters and Jack rafters

a few videos ago we covered calculating basic Rafters for a simple gable roof that's simple because simple Gable roofs have Rafters that are all the same that's what makes them simple hip roofs are more complicated not only do we need the common rafter length but we also need lengths for two other types of rafter hip Rafters which connect the ridge to the corners and Jack Rafters which are modified common rafters connect in the hips to the wall plates the bottom of a jack rafter is just like a common rafter but the length and bevel Direction varies hips have a lower pitch than common rafters because they cover a longer distance for the same height for this reason it's easier to walk up and down hips and valleys than straight up or down the roof you can determine the hip pitch by looking at your speed square or calculating it on a construction calculator there are two scales on a speed Square Commons and hip Val which means hips and valleys we'll talk about valleys later but you can see a 612 on a common scale is a little under 27° bur a 612 on a hip valve scale is a little under 20° talk about the cold shoulder with different geometry you need to make sure the roof doesn't come out looking humpy misaligned hips are usually caused by high heels wait a minute let me try that again the heel height of hips must match that of common rafters otherwise the hips will be humpy okay let's run through the calculations and see if we can rise to the challenge of Perfect Pitch to get the common rafter Dimensions we need to know the run and Pitch so punch 14 ft 11 in one4 and run then push six inch and Pitch hit diagonal to get 16t 8 and 716 which is the common rafter length excluding the tail so from the face of the Ridge board to the outside of the wall sheathing to find the hip length punch hip V that's the hip and Valley length again excluding the tail so 22 ft 4 and 7/8 in if you punch hip V again you get the plum cut angle 19 1/2 de and punching it again gives you the level cut or the seat cut which is a much more civilized temperature to find the Jack rafter lengths we're going to start punching the Jack button punch it once to get the rafter spacing 16 in on Center is the default if you like that number keep punching Jack if you don't like it pick another one punch it again to get the difference in length of each Jack rafter and punch it again to get the length of that first rafter which will be 15' 2 1/2 in you can keep punching it to get every other Jack rafter length until you get down to the corner where the length is zero don't forget to write those numbers down because we're going to start laying out and cutting rafters in the next [Music] video

Channel: ProTradeCraft

Views: 6,218

Keywords: remodeling, construction, building, carpentry, roof framing, hip roof, hip rafter, jack rafter, hip roof framing, rafter calculation, hip rafter calculation, jack rafter calculations, jack rafter calculation

Id: P0USmxLAHtA

Length: 3min 24sec (204 seconds)

Published: Tue Mar 12 2024