Carpentry & Home Improvement Skills : How to Build Rafters

Carpentry & Home Improvement Skills : How to Build Rafters


Rafters, one of the most interesting parts
of construction. I’m Robert Markey. I’ve been doing construction for many years, and we’re
going to talk about how to build a rafter. Let’s assume that you know what your pitch
is. Let’s say it’s eight and twelve for this one. And we’re going to assume you know what
your length of your rafter is, and that’s easy enough to calculate from the height and
from the horizontal distance. But for the rafter you want to use your framing square.
Use these little brass tweekers to set up on eight and twelve; give us our pitch and
make our top cut, top line, okay. That’s our peak, our ridge, okay. Next, you’ll want to
cut this so you can get a nice hook on your tape, and then you’re going to measure the
length of your rafter from the peak to the outside of your of your wall. And let’s assume
this rafter was a lot longer, and we’ve got our oh, a ten foot length, so we mark here
at ten feet. Then, we make the same angle, okay. The outside of your wall is here, so
you’ve calculated your distance to go from the outside of your wall to your ridge. If
your wall is a two by four it’s three and a half inches wide. Here’s your bird’s mouth,
okay? This comes right down the outside of your wall. If you got plywood you would have
made that four inches, okay. Fits basically the the layout from here. It depends on what
kind of, what kind of trim work you have. If you want to go straight out, and then have
a an end here for something like that, or if you want to do one of these. However however
it it ends up being that’s your cornice detail. The difficulty in the rafters is making sure
your length is right on the money. I’m Robert Markey, and we’re talking about how to make
a a rafter.

14 thoughts on “Carpentry & Home Improvement Skills : How to Build Rafters

  1. This is the most ridulous way to lay out a rafter. You walk the rafter length out with the square and not measure from the ridge because the ridge height hasn't been established yet. NEVER use square nuts because they come loose and you won't realize it till after it is too late.Your birds mouth has depth cut requirements you just don't measure 3.5" for the wall plate your birds mouth is required to overlap your exterior sheathing.Hire a professional framer unless your building a chicken coop

  2. wow all the sudden everyone becomes an expert huh just use a construction calculator if your to cheap to buy one then use the Hypotenuse formula and if didnt understand anything get someone who knows personally I dont like to use a framing square because its not exact on longer rafter remember each pencil line is almost 1/16" thick

  3. why not join the rest of the world and get metric…feet n inches died years ago…as for that tuition, crap……i doubt u could level water…

  4. @DRNEFDR Also on most framing squares it has the multiplier right next to the inches. You just times the lenght of the run by that number and don't forget to subtract half the diameter of the ridge. Bingo, rafter length.

  5. I am building a ramp for my shed, sounds simple. My run is 48 inches my rise will be 10.5 inches, what is my pitch? This is where it gets difficult instead of the rafter (which is actually my ramp stringer) resting on the top of a wall it will be resting on top of a concrete footing, so the bottom must be cut so it will lay flat, while the stringer rests square against the side of the shed (which could be considered the ridge), then I need to cut a birds mouth to rest on angle iron shed side.

  6. @bryans710 if your building is 12' wide and the ridge is in the middle then your 'run' is half that, it's 6'. if your pitch is 8/12 like this guy says, then for every 12 inches of run you have 8 inches of rise. since 6 feet is 6 sets of 12 inches you'll have six sets of 8 inches meaning your 'rise' will be 48 inches. since this forms a right triangle (rafter being the hypotenuse) you can do rise squared times run squared equals rafter squared. in this case (48^2)(72^2)=(x^2) x=the rafter length

  7. Here's an easy way to find the length of your rafter. Overhang + run x factor(hypotenuse) – half the ridge board and that will = the distance of your rafter. Ps make sure you square root your factor before you multiply it. Thumps up if this was helpfull to you!

  8. for real though its essential to know this but on a job site most of the time the trusses come pre assembled

  9. he said in 3 minutes what other guys take 2 videos to say… yay for the weird ass grey haired carpenter hippy guy 🙂 ha ha…

  10. I checked a lot of handbooks with woodworking plans. Instructions from woodprix are the best I think.

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