- Today, we're learning
how to frame a hip roof using a framing square and a calculator. Hip roofs like our mock-up here today are made up of common
rafters, hip rafters, and jack rafters. In order to frame a hip roof, you must have already calculated and installed your common rafters. Now because I've already done two videos on how to lay out and cut common rafters, which I'll link below, I'm not gonna get into too
much detail in this video. However, I will give you a quick overview demonstrating yet a faster way
to calculate common rafters. When using a construction calculator to solve for common rafters,
you only need two numbers, the run and the pitch. The run is half the
distance of the total span minus half the thickness
of the ridge material. For example, this mock-up has
a total span of four feet, which is measured from its outside edges. So half of that is 24 inches. The ridge is an inch and a half wide. So half of that would be
three-quarters of an inch. Therefore, 24 minus three-quarters leaves us with a run of 23 and a quarter. Pitch is how much the roof
rises per 12 inches of run. For example, for every 12
inches of horizontal run, our roof rises six inches. This number is completely
dependent on personal preference, codes, or specified by a designer. On the calculator, type
23 and one-quarter inch and press the run button. Then type six inches,
and then the pitch button followed by the diagonal button for a measurement of 26 inches. 26 inches is the rafters
diagonal measurement which is from this tip here
down to the black line. And it does not include the overhang. So, let's go over and do some
layout to figure this all out. The majority of our
layout will be done today using the framing square, that's actually attached
to a piece of wood with some simple clamps. What this will do is allow
the square to move freely and accurately over the lumber. To set up for a common rafter, line up the six mark on the tongue side with the edge of your wood. This represents the pitch or rise. Then line up the 12 inch
mark with the other side and clamp it in place. Again, this represents our run. Now slide to square up
to the top of the rafter, trace the tongue angle, and
cut the angle with a saw. From there, measure down
from the top of the rafter, 26 inches, make a mark
and draw a second line. So far, we've laid out
this part right here. And now we need to lay out and cut for the birdsmouth,
the soffit, and the fascia cut. The seat cut for the birdsmouth is to the right of this line. And it's four inches
long for this mock-up. So line up the four and draw a line. And that gets cut out. Next is the overhang, which
is five inches from this line. So line the tongue back
up, measure over five, make a mark, and draw another line. The last line to mark is the soffit cut, which forms the four-inch fascia. Measure down four inches, make a mark, and then draw a line. And this all gets cut out. Once everything is cut out, you now have a finished common rafter. Because we're focusing mainly
on building a hip roof today, we're actually gonna
use this common rafter that we just cut to start
forming today's hip roof. Once installed here, there common rafter becomes known as the king common
rafter or just king rafter. And it gets lined up
with the ridge at the top and on the center line down on the plate. And you may be wondering, how do you know where the common roof ends and the hip roof starts? Well, it's actually pretty simple. The hip roof starts 23 and quarter inches back from the edge of the building, which is exactly our run. Moving on, let's start
working on the hip rafters, which go from the bottom corner here all the way up to the ridge. If we look back at our calculator, you can see that it's still
showing our common rafter length of 26 inches. From there, all you have to do to find the length of the hip rafter is to push the hip and valley button for a total length of
34 and seven-eighths. Again, this measurement does
not include the overhang. So we'll need to add that just like we did for the common rafter. There's one more number
that we need to figure out before we clear the calculator out, and that is the jack rafter lengths. Still on the screen is
34 and seven-eighths. And all we have to do
to find the first jack is to hit the jack button
until you see jack number one, which for us is eight and an eighth. If you hit the button another time, you can see the jack two is zero inches. And it's zero because our roof is so small that there's no other jacks needed. If you had a larger roof, you would just continue to hit the button and cycle through all the jack
rafters needed for your roof. Because hip rafters are
at a 45 degree angle to the ridge board, they rise slower or more gradually than
the common rafter would. Therefore, we need to account for this by changing the run of
our square from 12 inches to 17 inches. Just make sure that when
you make that adjustment, double check that the tongue
measurement of six inches is still right on. The other thing to note
before we begin layout is that hip rafters
along with ridge boards are generally one size larger
than the rafters themselves. So for our example back here, we're using two by six rafters. So the ridge and the
hips are two by eights. All right, with the framing
square set to six and 17, mark out the top cut by drawing a line. And this time adding two more lines three-quarters of an inch to
the right and to the left. We will use these additional lines as guides to make our double bevel cut at the top of the rafter. If we look back at the two
rafters in our mock-up, you will see that the hip rafter has to be pointed in order to
fit tightly into that space. With the saw beveled to 45 degrees, cut the right line first,
which is the waste side, and then cut the other side. When you're done, your
cut should look like this. From there, take your tape measure and hook it over the point and measure down the rafter length, which is 34 and seven-eighths. Make a mark and draw another line. On common rafters, the seat
cut which is this part here, is generally the same
thickness of the exterior wall. In this case, it's four inches. However, we can't use that
same seat cut measurement for our hip rafters. But what we can use is
the height above plate. Height above plate is this
measurement right here. It's a straight line that goes right up to
the edge of the rafter. And in our case, it's four and a 16th. If we now go back to our layout, we can measure down four and a 16th, make a mark, and draw the seat cut. Now we're not quite done
with the seat cut yet. Because if we were to
cut that line right here, the rafter would fit,
but it would be too high. Again, because the rafter is
coming in at a 45 degree angle, it needs to sit down or be dropped so that the rafter edges meet like this. The amount of rafter drop is based on half the
thickness of the hip material. So in this case, it's
three-quarters of an inch. Back at the layout, measure to the right of this
line three-quarters of an inch, and make a short mark. Then remeasure down our four and one-16th, which is our height above
plate, and make another mark. The distance between these two lines is the amount of rafter
drop needed for this roof. All you have to do then
is slide the square up to that new line and
draw a new seat cut. Next up is the overhang amount. Because this is a hip rafter, we can't simply measure out five like we did with a common rafter. Rather, we need to figure out how far down the slope we need to go in order to locate the
correct amount of overhang. I know that's a little confusing. So let me draw a picture. What we're trying to figure out is how far down the slope we need to go to get the correct amount of overhang. So we don't know this number. However, we do know the other
two numbers in this equation and that is the overhang
amount of the common rafter, which is five inches, and the pitch of our roof is six inches. Therefore, on the calculator
type five inch run, six inch pitch. And because this is a hip
rafter and not a common rafter, we're gonna hit the hip and valley button for a total of seven and a half inches. If we go back to our layout, we can measure down now
seven and a half inches, make a mark, and draw our overhang. Again, because this is a hip rafter, this cut needs to have a double bevel cut just like at the top. So like before, we're gonna measure three-quarters
of an inch on either side and draw two lines. Remember, once both lines
are cut at a 45 degree bevel, the center line will end up being the tip of those two bevels. The last thing to lay out
would be the soffit cut. And in order to do that, we need to first extend our seat cut line over to meet the overhang
or fascia cut line. And now, it's back to the common rafter to measure the distance
between the seat cut and the soffit, which
is two and five-eighths. Transfer that measurement down from our extended seat cut line, make a mark, and draw the soffit cut line. Again, there's a lot of lines here, so let me darken them so
you can see more clearly. First we're cutting the
fascia, the heel cut, and the seat cut, which
makes up the birdsmouth. And then we're cutting the soffit. But remember that the center fascia line is cut using two 45 degree bevels. Cutting the waste side first
and then the other side. Be careful to position
(indistinct) material safely as you work through making each cut. With the hip now cut, it's a good idea to lay
out the 45 degree angle for the rafters. So, you know exactly where it fits. Once installed, double check it's fitting
tight to the exterior. And the top corners of the hip are lined up with the other king rafters. Because this hip fits, use it as a pattern to
cut out the remaining hip and install it. The last thing to do is lay
out and cut our jack rafters. Because this roof is laid
out 16 inches on center, let's pull a tape from the
left side of this king rafter, measure our 16 inches, draw a line, and mark an X where the
rafter gets installed. Because this roof is so small, it only needs one jack rafter. And if you remember the
length of that rafter is eight and an eighth. Now there's one thing to note about the Construction Pro Calculator and that it doesn't take into account the thickness of the hip when
calculating the jack rafters. Therefore, because our hip
is an inch and a half thick, we have to add seven-16th to the overall length of the jack rafters in order to get them to
land exactly 16 on center. So all we have to do is
simply add seven-16ths to our eight and eighth to
get a total jack rafter length of eight nine-16ths. To lay out the jack rafters, you have to put your
square back to a six, 12. Again, because we're not
cutting hips anymore. Jack rafters also have 45
degree bevels at the top and a common rafter seat
cut and tail assembly. Therefore, you can lay these
out individually if you want, or you can make a copy
of the common rafter tail simply by tracing it out
and using it as a pattern. It starts by laying out the top angle set to your six and 12. Set this all at a 45 degree
bevel and make your cut. Measure down from the
long point of that bevel eight and nine-16ths
and draw another line. From there, line up your pattern, trace it out, and make the cuts. Now because some of the jack rafters are on the opposite side of the hip, you'll have to make mirrored copies so that the 45 degree angles are going in the right direction. To do that, simply lay one jack down
with a long point facing down and trace the whole jack out. And now when you cut this new jack, just make sure that you're cutting with the saw beveled in
the opposite direction so that you're making a mirrored copy. With everything cut, install the remaining
jacks to finish the roof. As a reminder, this is
just a mock-up roof. So you need to make sure to check with all of
your local building codes so you can find the correct ways to attach and size all the framing members. Now, we went over a lot of
information really quickly. So I broken down this video into chapters so you can go back and
do each step easily. So, if you have any questions, hit me up in the comment section below. You can find me on Instagram. That always works as well. Thank you so much for watching today. See you in the next video. (soft music)
