If you are beginning a new home project or having your roof replaced, you may be wondering if the contractor is giving you the correct estimate. You may also want to have your roof’s measurements for other purposes. In either case, you need an accurate record of your roof’s measurements and area. There are several ways to do this, and we are going to look at three of the most common ways below.
For Obvious Shapes
Most homes have roofs that are of a simple shape. These are usually rectangles or squats. For homes with simple and obvious shapes, all you need to do is measure your roof section dimensions. You will need to climb on the roof and physically measure the length and width of rectangular and square sections as well as the length and width and height of triangular sections.
All that remains is to use the formula for calculating the area of the respective shapes and add them up.
Measuring from the Ground
If you do not want to climb onto your roof, the best way to measure your roof is to use the estimation of the roof’s pitch as well as the area of the house. Do note that ground measurements work well only for gabled roofs as you only have two roof sections to measure. For hip roofs and other roof designs, you will need to climb on the roof or work with a contractor.
To measure the roof from the ground, you need to head outside and start stepping backwards until you can barely see the slope of the roof. You need to measure the distance between you and the edge of the roof at the spot where the plane of the roof is just visible. Note this number in inches. This is the horizontal run.
Next, stand directly underneath the roof and measure the distance between your eye and the edge of the roof at the spot you were looking at earlier. Record this distance in inches. This is the roof rise.
Next, divide the roof rise by the horizontal rise to end up with a simplified fraction. For example, if the roof rise is 60 inches and the horizontal run is 120 inches, the fraction will be 6/12.
Measuring the Property
Now, you need to measure the base area of the house. This can be done easily by using a tape measure to measure the length and width of the house from one edge to the other for two perpendicular walls. Multiplying these areas gives you the base area.
Finding the Roof Area
Now that you have the roof pitch, you need to find the pitch multiplier. You can easily find a pitch multiplier table online and these multipliers make it easy to find the roof area without climbing on top.
Multiply the length of the house with the width and then multiply that figure with the pitch multiplier to find the area of the roof.
Using a Diagram
Another way to get an accurate measure of your roof, apart from using formulas of obvious shapes and using the roof pitch, is diagramming. Here, you will need to make an accurate representation of your house on graph paper. This means that you have to climb on the roof and start measuring.
Once you are safely on the roof (do not forget a harness), measure the length and width of all sides of the roof. If you have more than one plane or section on the roof, you need to take measurements of all these planes and sections. Next, you need to measure all additional structures separately. You need to ensure that all measurements are precise before you start graphing.
Once you have measured everything and ensured that the measurements are correct, it is time to transfer everything onto paper. You do not need to be accurate with the drawing but ensure that all parts of the drawing are an actual representation of the actual shapes of the different sections. Ensure each diagram you draw for different sections of the house is accurately labeled with accurate dimensions inside or alongside it. Do not round up the measurements as they can mess up the calculations;instead, use them as is.
Now, divide the diagrams you have drawn into simple geometric shapes like squares, triangles, and rectangles. Use the respective formulas of these shapes to find the area of each shape. Once done, add up all the areas to find the total area of your roof.
There are various ways to measure your roof, with each method having a different level of accuracy. When choosing from either method, ensure that you use a method that works well for the roof you have. For a simple roof, measuring the roof and using the correct formulas to calculate the area of each section helps, while drawing a diagram that outlines all sections of a roof will work for complicated roofs.