Welcome to our DIY guide on how to figure square footage for roof shingles. Whether you are a homeowner looking to replace your shingles or a contractor planning a roofing project, knowing how to calculate the square footage accurately is essential. By following these simple steps, you can ensure that you purchase the right amount of materials and avoid any unnecessary expenses. So, let's dive in and learn how to calculate the square footage for your roof shingles!
Step 1: Measure the Roof
The first step in figuring out the square footage for roof shingles is to accurately measure the dimensions of your roof. Start by measuring the length and width of each section of your roof. If your roof has multiple sections, measure them individually and then add them together.

Example:
Let's say your roof has two sections. Section A measures 30 feet in length and 20 feet in width, while Section B measures 15 feet in length and 10 feet in width. To calculate the total square footage, you would add the measurements of both sections:
Section A: 30 ft x 20 ft = 600 square feet
Section B: 15 ft x 10 ft = 150 square feet
Total Square Footage: 600 square feet + 150 square feet = 750 square feet
Step 2: Accounting for Pitch
Roofs with a steep pitch require more shingles than roofs with a shallow pitch. The pitch or slope of a roof is determined by the vertical rise in inches for every 12 inches of horizontal run. To account for the pitch, you need to calculate the roof's "pitch factor" and multiply it by the total square footage.
Example:
Let's say your roof has a pitch of 6:12. This means that for every 12 inches of horizontal run, the roof rises 6 inches vertically. To calculate the pitch factor, divide the rise by the run:
Pitch Factor = Rise / Run
Rise = 6 inches
Run = 12 inches
Pitch Factor = 6 / 12 = 0.5
To calculate the adjusted square footage, multiply the total square footage by the pitch factor:
Adjusted Square Footage = Total Square Footage x Pitch Factor
Adjusted Square Footage = 750 square feet x 0.5 = 375 square feet
Step 3: Adding the Waste Factor
When installing roof shingles, it's important to account for waste and cut-offs. This is known as the waste factor and is typically around 10%. By adding the waste factor to the adjusted square footage, you can ensure that you have enough materials to complete the job.
Example:
If the waste factor is 10%, you would multiply the adjusted square footage by 1.1:
Total Square Footage with Waste = Adjusted Square Footage x 1.1
Total Square Footage with Waste = 375 square feet x 1.1 = 412.5 square feet
Step 4: Choosing the Right Shingle Bundle
Now that you have calculated the total square footage with waste, you can determine how many shingle bundles you will need. Most shingle bundles cover approximately 33.3 square feet. To find the number of bundles, divide the total square footage with waste by 33.3.
Example:
Number of Shingle Bundles = Total Square Footage with Waste / 33.3
Number of Shingle Bundles = 412.5 square feet / 33.3 = 12.38 bundles
Round up to the nearest whole number to ensure you have enough bundles. In this case, you would need 13 shingle bundles.
By following these four steps, you can accurately figure out the square footage for your roof shingles and determine the number of shingle bundles you will need. Remember to always account for the pitch and waste factor to ensure you have enough materials for your roofing project. Now you can confidently tackle your roof replacement or repair knowing you have the right calculations!
Summary:
Step | Description |
---|---|
Step 1 | Measure the dimensions of your roof and add them together. |
Step 2 | Calculate the pitch factor and multiply it by the total square footage. |
Step 3 | Add the waste factor to the adjusted square footage. |
Step 4 | Determine the number of shingle bundles needed. |