![]() Easy just measure 8 1/2" along the base of your pitch triangle, square it up and measure the sloping length of 11 1/8".Fro the pitch triangle above we know that for every foot of horizontal width the rafter is 1'-3 5/8"long.ġ6 X 1'-3 5/8" is 20' 10", that takes care of the long length to the nearest foot.You might be thinking that it is OK to draw a small eaves out full size, but what about the main rafter with this system? No sweat. No big deal at all, when I was doing the sketch I would have drawn the Hardie soffit on the slope, with the pitch triangle close to make sure that I have the rafter drawn at the correct angle.Įave rafter length- The adjustment at the ridge Of course I could have it completely wrong, the intention may be to use the Hardie Soffit to line the eaves on the slope. Safer.Įave rafter length- A layout where the soffit slopes with the roof. In this instance though I would allow a few inches extra and cut the rafter ends off exactly when the roof is fixed.What's the point of using a $300 roofing calculator if you forget to allow for the gap between the brick veneer and the frame? This is the real reason why I say sketch it out, the act of drawing and the visual inspection is a great memory jogger.This has given me an extremely accurate result, far more accurate than a calculator would have if I had, say forgotten about the groove in the fascia.While drawing my sketch I made allowances also for the fact that part of the soffit sheet may be going into a groove in the fascia, and I also allowed a bit of clearance at the wall.In my sketch I have come up with an extra length of 1'-11 1/4".Similarly the gap between the brick and the framed wall.I don't know how wide the bricks are, so I have drawn my sketch of them to be 4 1/2".In the sketch on the right I have put them at 6" apart to represent a 6" rafter. So, back to the drawing, draw out the pitch triangle again, full size, and this time draw a couple of lines parallel to the sloping side of it, the hypotenuse.I suspect that it is not so simple though, with the mention of brick veneer. So looking at the pitch triangle he already has the length of the rafter section that will span 12". Check it out in the right hand menu at the top!Ī bit of luck, the soffit size that Allen is using, is 12". I have already written a basic primer about calculator work, and as I use practical example to illustrate the subject, it may be of interest. Later when I get my act into gear I will be writing an extensive E-Book on roofing, in which will go into detail of solving roofing problems with a cheap electronic calculator as well as drawing to scale. The actual fact of drawing it out makes you less likely to forget to allow for some detail. It is not as accurate as it could be, but is has the benefit of being practically foolproof. ![]() We can of course get this information in a few different ways, and I say draw it out, mainly because, for a one off job, it is a simple way to learn how to do it. More importantly you can measure the length of the sloping side and make a note of it.You can now use that triangle to set your adjustable bevel(s) to.You will finish up with a triangle that defines the angle of the roof.Join the two marks together with a straight pencil line.Mark along the bottom, 12" from the corner.First get a piece of paper, ply or your kitchen table, anything with a square edge and a pencil and a straightedge.I have done some of this before, in my rafter cuts page, but it does no harm repeat some of it here. that the roof covers then it also rises 10". Rafters, does not include hip or valley rafters.Įlevation under 600’ above Sea Level 70 lb.Eave rafter length- Sketch of the pitch triangle.Īllen is from the US, so we are working in the way that he as given the roof angle, in a ratio 10:12. at an elevation of 900 feet above sea level. When sizing structural ridge beams, and hip rafter beams remember to use the 80 lb. The charts below will give you an idea of what we will be inspecting for on a typical roof with ceiling joist located at top plate of wall. Re: Ground Snow loads: the requirements have been raised from 50 Lb.
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