[quote=“wadman1”]Anyone do aerial roof measurements your self? I have seen all (most) the paid sites and i see that they are great and i’m sure some of you use them all the time. thats one way to do it but if i get 15 or more calls a week that can add up quick. I use bing, google maps and google earth and do great but i know there is a better way or site out there. or at least some tools to help me get better at it. I can’t swallow paying $50 to $100 a report when all i’m doing is biding the job. It only takes me 5 mins to do it my self and i’m almost all ways with in a bundle or 2 the way i do it now. any one have a site or program i should look into. Thank ahead of time for any input.
Also i would like to find or make a chart that has the rake edge numbers per pitch
If the house is 28 feet wide and a 4 pitch it is 16 foot from the drip to peak
If the house is 32 feet wide and a 4 pitch it is 18 foot from the drip to peak
If the house is 28 feet wide and a 6 pitch it is 19 foot from the drip to peak
and so on[/quote]
wadman, if I understand you correctly, you are talking about a looking into the rake and it the house width you refer to is between the eaves? I must not be understanding you correctly because if the width is 28 ft, 1/2 would be 14 feet. The rise in this case would be 4.667 feet. I’m thinking what you are looking for is the rafter length, that only makes sense. So it is the hypotenuse of the triangle you are wanting to solve for.
Assuming you know the width, then 1/2 of that is the “adjacent” length of the triangle formed between the rafters and the base. You can easily solve for the rise, it would be x/12 x 1/2 of the width (the adjacent) with x being the pitch. Then you would solve for the hypotenuse by dividing the adjacent length by the cosine of the angle formed between the rafters and the base.
Do you have Excel? If so, I could put together a simple excel sheet where you could plug in the width and the pitch and it would automatically calculate the hypotenuse (rafter length) and send it to you. Every pitch has a fixed angle (example: 7/12 is 30.26 degrees) so this is fairly simple.
Here’s another way that is probably easier. rafter length = 1/2 width / cosine of the angle. If you simply look up the cosine values for the various pitches, divide that into 1, you will have the multiplier you want to solve for the rafter length. For example, the pitch angle for 6/12 is 26.57 degrees. The cosine of 26.57 is .8943. If you take your example, if the width of the house is 28, the adjacent or 1/2 of that would be 14. 14 divided by .8943 = 15.65 ft (not exactly 16 feet). The easier way to do this would be to divide 1 by .8943 which = 1.12. If you multiply the base or adjacent by this number, you get the rafter or hypotenuse (1.12 x 14 = 15.65). Just do this math for all the pitches you want and you’ll have a multiplier for each pitch that would always give you the rather length when you know the width and the pitch.
Below are the multipliers you can use to calculate the rafter length when you know the width and the pitch. Just take 1/2 of the width and multiply by the number associated with the pitch below and it will give you the rafter length:
I think this is what you’re looking for. If not, let me know. I did this pretty quick but I think I got the numbers correct.