Measuring Roofing Square Footage Manually: A Step-By-Step Guide

There’s a lot of technical jargon involved in home maintenance. As homeowners, it’s our responsibility to understand these terms to help us plan repairs or new roof installations.

Roofing square footage is one of the most essential of these terms. You can call a contractor to calculate this or do it yourself. If you want to go DIY, here’s a list of the equipment you’d need.

Roof Measuring Equipment

Measuring a roof can be difficult, especially for those who have little to no experience. But if you’re up for the challenge, it’s best to have the following tools to ensure accuracy and safety:

• Ladder
• Level
• Calculator
• Harness
• Measuring tape
• Pen and paper (you can also take notes using your phone)

As a precaution, you need to wear the proper safety equipment. Even professionals wear them to help reduce the risk of accidents and injuries.

Roof Measurement Terminology

If you want to measure your roof, you need to learn the basic roofing-specific terms. Learning these allows you to understand what you need to measure to get an accurate calculation.

Roofing Square

One roofing square is equal to 100 square feet. We use this measurement to know the number of shingles needed for every 100 sq. ft of the rooftop.

Before planning for repairs, we need to calculate the roofing square to identify how many materials are needed. This covers everything from asphalt all the way to the underlayment.

Plane

Planes make up our roof. They’re the foundation shingles and other roofing materials are laid on. If you have a flat roof, you’ve got one plane. A simple gable roof has two planes.

Source: Unsplash
The more architecturally complex your roof is, the more planes you can have. The image above has around 8 planes you need to measure. We get the roofing square of a roof by getting the sum of all the planes.

Shingle Bundles

Shingles are sold in bundles. Our measurements help us know how many bundles we need. This is thanks to manufacturers doing the guesswork for us, estimating the bundles per square.

The number of shingles in a bundle depends on the design or shape. In most cases, three bundles could be enough for one roofing square.

If you have a gable roof measuring 2000 sq. ft., you’d need 60 shingle bundles. Remember, one roofing square equals 100 sq. ft. We multiply the square feet by 3 then divide it by 100 sq. ft.

(2000 sq. ft)(3) = 6,000. Then divide 6,000 by 100 sq. feet to get 60 shingle bundles. But, you don’t want to buy the exact computation. To be safe, you can buy 10-15% more shingles.

How To Measure Roofing Square Footage

Now that we know the terms, let’s take a look at how we can measure roofing square footage manually. As always, refer back to the list of measuring equipment to ensure accuracy.

Identify the number of planes: If you want to get the overall roofing square footage, you need to measure each plane on your roof.

Measure each plane: To get the area of the planes, simply multiply their length and width.

Add the sum of the plane’s areas: Get the total square footage of each plane.

Divide the total area by 100 sq. ft.: Remember, one square roofing is equal to 100 square feet.

Here’s an example. Let’s say your home has a simple gimbal roof with two planes. Each of the planes has a length of 25 and a width of 26. That means the area of each is 650 sq. ft.

After adding the sum of the two areas, we get 1300 square feet. Divide this by 100 to get 13 squares.

But before calling it a day, we need to account for the roof slope. How steep your roof is determines whether or not you need more materials.

To calculate the roof slope, identify how many inches it rises vertically for every 12 inches it extends horizontally. So, a roof with a vertical rise of 5 inches gets you a ratio of 5:12.

After we get the slope, we need to know the “slope factor” to help us identify how many extra roofing squares we need. Luckily, roofing manufacturers share this info online for free. So, we just need to refer to the chart below:

In our example, we have a roof with a slow of 5:12, the slope factor is 1.0833. We multiply this sloping factor by our initial calculation of the required sloping squares. In our case, this would be 13 squares x 1.0833 or 14.08 squares.

Don’t just buy shingle bundles based on your initial calculation. Factor in the design of your roof, the shape of the shingles, and potential errors during repairs. A safe bet would be to add at least 10% to 15% more shingles.

Roof Measuring Tips

If you want to streamline roof measuring, follow these tips every professional contractor follows:

• Plan out everything and build an organized system before starting any project.
• Prepare all the tools and materials needed before starting roof repairs.
• Familiarize yourself with the steps needed for measurement and repairs.
• Account for structures in your roof such as ridges and valleys.
• Subtract the area from structures like chimneys and pipes that don’t need shingles.

Key Takeaways

Roof repairs or renovations require you to know the proper roofing square footage. This allows you to identify the right amount of materials needed to finish the project and the budget.

So, before you invest both time and money into roof measurements, consider the following:

• Always prioritize safety when doing any type of work on your roof.
• Learn the definition of roofing terms such as roofing square, plane, and shingle bundles.
• Prepare the proper equipment to ensure accuracy and safety.
• Account for the slope to get a better estimation of the needed materials.
• If you don’t know the slope, a good guess is to use 10%-15% more shingles.

Roof measurements can be tough, especially for those with no experience. To ensure the most accurate results, contact qualified contractors.

If you’re looking for the best roofing contractor in Newton, PA, Trenton has you covered! Request a free estimate today!