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How To Frame A Hip Roof – Including A Common Rafter Review

– 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 layo

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