If you plan to re-roof or install a new roof on your home, you must know how to measure a roof for shingles. Getting the roof’s accurate measurements might seem daunting for many DIYers, but it’s not when you use the right tools and follow the correct procedure.
So, how do you measure a roof for shingles?
A lot goes into measuring the entire roof area for shingles, especially for complex roof structures. You’ll have to get the correct estimate while ensuring your safety during the process. That’s because you might have to get to the rooftop to measure the planes.
As you measure the roof, you must also account for the extra shingles needed for overlaps, waste, and starter shingles. So, before you start shopping for roofing materials, you need to know how to measure a hip roof for shingles.
If you’re unsure how to measure a roof for shingles, worry no more. This guide explores all the methods of measuring the rooftop for a successful shingle installation project. You’ll learn all the steps you must follow to get the correct measurement of roof planes.
That said, let’s dive into the steps.
How to Measure My Roof for Shingles
Measuring a roof for shingles involves many steps. To get a good estimation, you’ll determine the square footage of the house and multiply it by the roof’s pitch. But for accurate measurements, it’s good to measure each plane on the rooftop.
Once you get the total area of your roof surface, use the measurement to determine the number of shingles needed for the roof. Unfortunately, some roofs are hard to access, making it tricky for homeowners to take the correct measurements.
The bottom line for measuring a roof for shingles is to calculate the roof’s pitch and the building’s base area. Ground measures are ideal for gabled roofs with two rectangular pitches. But for complex roof structures, you’ll need a professional roofer to help you.
Now, let’s dive deeper into the steps of how to measure my roof for shingles.
Step 1: Determine Your Home’s Area
Determine your home’s base area by measuring the width and length. Find out the distance between the edge of one side of the eaves to the other edge on the same wall and note down the figure in feet. Use the measurement as the base width.
Do the same to the perpendicular wall to determine the base length. Then, multiply the structure’s base length and width to determine the roof’s base area.
For example, if the base width is 30 feet and the base length is 60 feet, you’ll multiply the two dimensions to find the roof’s total base area of 1,800 square feet.
Step 2: Determine the Roof’s Pitch
You can determine the roof’s pitch from the ground or attic. The latter will bear the most accurate results as there’s no roofing material to block the way.
So, how do you measure a roof’s pitch from the attic?
- Access one of the rafters in the attic space: Get to a rafter in the attic space to get the measurements. Alternatively, you can take measures from the overhang of one rafter at the roof’s end or a barge rafter on the gables’ side.
- Place a level along the rafter’s underside: Use the carpenter’s level to find the rafter’s measurements by placing it on the rafter’s bottom. Adjust the level to center the bubble between the two lines.
- Locate the 12-inch calibration on the level: The standard measuring the length of the rafter for a pitch in the United States is 12 inches. If the level you are using lacks the 12-inch mark, use a tape measure to mark the 12-inch point.
- Measure the vertical distance between the level and rafter: By extending the tape measure perpendicularly to the level, find the distance between the 12-inch mark and the underside of the rafter to get the roof’s pitch. For example, if the vertical distance is six inches at the 12-inch mark, the roof’s pitch will be 6/12. That translates to a rise of six inches every one foot.
Step 3: Determine the Roof’s Slope
A roof’s slope refers to the ratio of the vertical distance (rise) to the horizontal distance (run). You don’t have to simplify the measurements found. Instead, use them as they are. For instance, if your roof rises 6 inches every 12 inches, the slope will be 6:12.
You can use your ratios to find the slope factor. A roof with a slope of 6:12 has a slope factor of 1.12.
Step 4: Multiply the Slope Factor by the Base Area to Find the Roofs Area
Multiplying the slope factor by the building’s base area will give you the approximate area of the roof. For example, if the building has a base area of 1,800 square feet and a slope factor of 1.12, the total area of the roof surface will be 2,016 square feet.
The figure is just an estimation of the roof’s total area. It doesn’t account for the roof’s overhangs or differences in the roof pitch. For that reason, it makes more sense to increase the estimated area by around five percent to take care of the discrepancies.
How to Determine the Number of Shingles Required
Now that you’ve calculated the total area of your roof surface, you can determine the number of shingles needed to complete the house. Shingles usually come in bundles, with one bundle enough to cover a third (1/3) of a square.
Next, convert the total square footage to squares, then multiply the number of squares by a third. That will give you the approximate number of bundles needed for the roofing project. Finally, increase the number of bundles by 15 percent to account for waste.
With this guide, determining the number of shingles required for your roof is no longer tricky, even if you didn’t know how to measure a roof for shingles. All you have to do is to follow the correct procedure. However, if you find it challenging to measure your roof for shingles, you can consult professional roofers like Roof Masters for help. Contact us today to talk with one of our professional roofers about your roofing project.