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  1. #1
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    Oct 2006
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    Greensboro, NC
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    Default "From The Ground" Roof Slope Calculator

    Need help answering this question...

    Is there a from the ground roof slope calculator to help with making accurate roof measurements ?

    Have a family member who will be selling roofing, not a pro, but a smart guy who's asking a good question.

    How do you guys make accurate measurements or train someone to do so ?

    I just looked at Android apps but I don't think he has a a smart phone yet.
    Steve

    "Get three coffins ready" - A Fistful of Dollars 1964

    http://youtu.be/KZ_7br_3y54

  2. #2
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    Default Re: "From The Ground" Roof Slope Calculator

    I actually have a little plastic GAF card in my truck that is about the size of a large credit card. The card has all different shapes on it that represent roof slopes. There is a table that shows the rafter slope/ft of run. The idea is that you hold up the card to an area you can see and when you identify the slope you can use the chart and building width to come up with a number.

    Its not bad for boxes with no valleys or dormers. I rarely use it because I rarely see a plain square box. I can estimate relatively close from the ground based on experience but a novice would never be acurate. If hes selling on commission he will risk being high or losing money to the installers if hes short.
    Tom

  3. #3
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    Portland, OR
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    Default Re: "From The Ground" Roof Slope Calculator

    How hard is it to get on a ladder an put a digital level on a piece of the roof near the eave? Folding ladder works fine if one is not working out of a truck for estimating

  4. #4
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    Default Re: "From The Ground" Roof Slope Calculator

    Oh, and if you can't get a ladder to the eave, but you can position yourself to sight parallel to the roof, just do that sighting along the top of a digital level, hit the hold button, and read the result

  5. #5
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    Mar 2006
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    Boise, Idaho
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    Default Re: "From The Ground" Roof Slope Calculator

    Would a speed square work for your guy?
    It is a simple matter of being patient. I do patience very well, except for the waiting part. That's the one aspect of patience that still bites me.

    I'm not saying I'm Superman. What I'm saying is no one has ever seen me and Superman in the same room together.

    ParkWest Homes LLC
    Working Man Online Store
    Living Healthy

  6. #6
    Join Date
    Dec 2009
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    Sterling Heights, MI
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    4,664

    Default Re: "From The Ground" Roof Slope Calculator

    Quote Originally Posted by Happy Home View Post
    Need help answering this question...

    Is there a from the ground roof slope calculator to help with making accurate roof measurements ?

    Have a family member who will be selling roofing, not a pro, but a smart guy who's asking a good question.

    How do you guys make accurate measurements or train someone to do so ?

    I just looked at Android apps but I don't think he has a a smart phone yet.
    I use the Geoestimator "Pitch Gauge" on my Iphone. I don't know if you can "accurately" estimate anything from the ground but I seem to do a fairly good job at estimating the slope using that tool. I often combine it with the Google street view to estimate the slope on roofs. I measure the roofs with Google Earth and together with the pitch gauge, I create the estimate sitting at my laptop before I go to the appointment.

    For me, it's plenty accurate enough for most situations. I primarily deal with insurance replacements, so the actual dollar amount will be hashed out at a later date. However, I believe my estimate is close enough in most situations that I would be willing to use my number to make a firm offer. I've won several contracts using this method simply because I'd be the only estimator willing to make a firm offer.

    I think we all can agree that the geometry of standing on the street and looking at a roof slope is inexact science. However, I doubt that the slope will be off more than an inch, if the alignment is anywhere near square from the elevation view. That error, will easily be absorbed by the inexact guesstimate of the waste factor.

  7. #7
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    Default Re: "From The Ground" Roof Slope Calculator

    Quote Originally Posted by parkwest View Post
    Would a speed square work for your guy?
    A speed square works too. A regular framing square works too.

  8. #8
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    Jul 2007
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    Northern Jersey
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    Default Re: "From The Ground" Roof Slope Calculator

    Another thing I would do occassion is count the course of siding on the gable then do the math.

    If I was going to put a ladder up to the gutter I wouldnt waste my time with pitch calculators I would just slide the tape up the slope/upside down so it dont bump every course.
    Tom

  9. #9
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    Nov 2004
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    Boston, MA
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    Default Re: "From The Ground" Roof Slope Calculator

    Guys,

    On most stock/spec houses the pitches are all pretty much predictable. You have the 10's and the lower slopes over porches, etc.

    I can get close just by looking at it and I'm a dumbass architect.
    "First we finish the game, then we’ll deal with the Armada!"

    Sir Frances Drake

  10. #10
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    Mar 2006
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    Boise, Idaho
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    Default Re: "From The Ground" Roof Slope Calculator

    Quote Originally Posted by Ted S. View Post
    Guys,

    On most stock/spec houses the pitches are all pretty much predictable. You have the 10's and the lower slopes over porches, etc.

    I can get close just by looking at it and I'm a dumbass architect.
    I don't think Steve in the OP wants to wait for his new guy to get a few decades of roof designing experience before he can use him. lol
    It is a simple matter of being patient. I do patience very well, except for the waiting part. That's the one aspect of patience that still bites me.

    I'm not saying I'm Superman. What I'm saying is no one has ever seen me and Superman in the same room together.

    ParkWest Homes LLC
    Working Man Online Store
    Living Healthy

  11. #11
    Join Date
    Oct 2006
    Location
    Greensboro, NC
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    1,563

    Default Re: "From The Ground" Roof Slope Calculator

    Thanks a lot for this information.
    Steve

    "Get three coffins ready" - A Fistful of Dollars 1964

    http://youtu.be/KZ_7br_3y54

  12. #12
    Join Date
    Dec 2009
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    Sterling Heights, MI
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    Default Re: "From The Ground" Roof Slope Calculator

    The most important issue for the new sales guys is to accurately determine the angle, when approaching certain slopes. For my pricing systems, I need to know when a roof is 2 to 4 because they get double felted. I need to know if it's a 7 or 8. A 7 is considered "walkable" and an 8 gets the first level of "steep" charges. The next change for steep comes at 10. Some vendors have different price points so at some point, I need to accurately calculate the slope. The pitch guage on my Iphone does that. I either lay it against the roof rake board, or lay a clipboard on the shingles (to smooth out the plane) and lay the phone on the clipboard.

    So, yes, I can make a fairly accurate guess by looking at the roof by eye, and by walking on it, but if it's close to an 8, or close to a 2 or 4, I need to get it right to get the billing right.

  13. #13
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    Jul 2007
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    Northern Jersey
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    Default Re: "From The Ground" Roof Slope Calculator

    Jim good points for sure I do the same thing and a new salesman would want to learn as much about his product as possible. Since everyone want their installers to be certified that usually means using all the manufacturers venting & under layment accessories.

    Jim I half lap my paper on low pitchs for years its much better practice and not something you see guys doing. I half lap my first course of paper on all walkable roofs for greater holding power. When papering over ice shield it will prevent the first course from tearing out.
    Tom

  14. #14
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    Nov 2004
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    Boston, MA
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    Default Re: "From The Ground" Roof Slope Calculator

    Jim,

    What App do you have that does pitch? I have tried a few, but can't find a good one that does pitch.
    "First we finish the game, then we’ll deal with the Armada!"

    Sir Frances Drake

  15. #15
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    midwestish
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    Default Re: "From The Ground" Roof Slope Calculator

    “I find the curiosity of our men with respect to this animal is pretty much satisfied.”
    ~ Meriwether Lewis

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