Understanding The Use Of Roof Pitch Tables
Although it is not necessarily difficult for you to find roof pitch tables, especially whenever you are on the Internet, it may be difficult for you to understand exactly how to use them. In order for you to get started using these tables, you need to have access to a good calculator, along with being able to understand the figuring behind coming up with the general pitch of the roof. By looking at some examples, you may be able to figure it out rather easily, but it is still going to require some calculations on your part. Here is a little bit about roof pitch tables, and some of the math that goes into figuring out the pitch of your own roof.
In order to figure out the pitch of your roof manually, you're going to need to know to measurements so that you can get started. The first thing that you're going to need to know is the run of the roof, which is a horizontal line from the eve of the roof all the way to the lower edge of the roof line. This can be a little bit difficult to obtain, especially if the roof is extremely large. One way for you to be able to get this measurement, however, is to measure the overall width of the entire roof and then to divide it in two. That is, of course, provided the roof is split in the middle by the eve.
Another number that you're going to need is the rise of the roof, which is the distance from the lower part of the roof to the upper part of the roof measured on a vertical line. Again, you may need to use a little bit of ingenuity in order to get this measurement. I find that the easiest way to get it is to measure down from the eve of the roof on the side of the house and intersect with a horizontal line that comes across from the lower part of the roof, except if you are roofing a shed roof.
Now is the time where you need to calculator. You must divide the rise by the run in order to get the tangent, which will then be used in figuring out the actual pitch. This is done by comparing the tangent number with the roof pitch tables that you have either downloaded off of the Internet or have in some way or another. By way of examples, a roof with an equal rise and run will give you a 45 degree pitch.
Of course, putting this to use in the real world may be a little bit more trouble than what it's worth. Although it certainly is possible for you to do this type of figuring with a calculator and holding roof pitch tables in your hand, it may be worth your time to pick up a tool in the store which will calculate this for you automatically - do this even before building rafters. By placing the tool on your roof, a floating needle will give you the pitch of the roof which will be close enough in order for you to do any type of figuring that is necessary.
