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What is a Roofing Square & How to Find the Square Footage of a Roof

When you’re planning to repair or replace your roof, you’ll encounter many roofing terms that might be new to you. One crucial term is “roofing square”. But what exactly is a roofing square?

A roofing square is a standard unit of measurement in the roofing industry, equal to 100 square feet of roof surface. Understanding this concept is essential for homeowners because it directly affects the cost estimation, materials needed, and labour involved in a roofing project.

In this blog post, we’ll dive into what a roofing square is and how to calculate the square footage of your roof. By the end, you’ll have a clear understanding of how these measurements impact your roofing project. So, let’s get started and demystify the roofing square!

Understanding the Term “Roofing Square”

A roofing square is a fundamental measurement in the roofing industry. Simply put, a roofing square equals 100 square feet of roof surface. This standard unit helps roofing professionals estimate the amount of materials and labour needed for a roofing project accurately.

Knowing what is a roofing square is essential for several reasons. First, it allows homeowners to understand cost estimates provided by roofing contractors. When a contractor mentions the price per roofing square, you can easily calculate the total cost based on the number of squares your roof has. Additionally, it helps in determining how much roofing material is required, ensuring you purchase just the right amount without wastage.

Moreover, understanding roofing squares can help you compare quotes from different contractors more effectively. By knowing the size of your roof in squares, you can better gauge the value of each quote.

Importance of Knowing Your Roofing Square

Knowing your roofing square is crucial for various reasons beyond just cost estimation and budgeting. Firstly, it directly influences the selection and quantity of materials. For example, different roofing materials like tiles, shingles, or metal panels are packaged and priced based on roofing squares. By knowing your roof’s size in squares, you can purchase the exact amount needed, avoiding both shortages and excess materials.

Additionally, understanding roofing squares helps in planning the logistics of your project. For instance, if you’re using slate tiles, each square will require a specific number of tiles and fasteners. This precise calculation ensures that your project progresses smoothly without delays caused by waiting for additional supplies.

Furthermore, having an accurate measurement of your roofing square aids in labour planning. Roofing contractors estimate the time and workforce needed based on the number of squares. For example, a roof with 20 squares might require a team of four roofers working over several days. This detailed planning helps you understand the scope and timeline of the project, allowing you to manage expectations and plan accordingly.

Steps to Calculate Your Roof’s Square Footage

Step 1: Determine Your Home’s Footprint

To calculate the square footage of your roof, you first need to determine your home’s footprint. The footprint is the area your home covers on the ground, and it forms the base for your roofing square calculations.

One simple method to measure your home’s footprint is by using a measuring tape. Start by measuring the length and width of your home. For example, if your home is 40 feet long and 30 feet wide, your footprint would be 1,200 square feet (40 x 30 = 1,200).

If you don’t have a measuring tape handy, you can estimate the dimensions by using your stride. The average person’s stride is approximately 2.5 feet. Walk the length and width of your home, counting your steps. Multiply the number of steps by 2.5 to get the length and width in feet.

If you take 16 steps along the length of your home, that’s roughly 40 feet (16 x 2.5 = 40). Similarly, if you take 12 steps along the width, that’s about 30 feet (12 x 2.5 = 30). By using these measurements, you can determine your home’s footprint, which is essential for the next steps in calculating your roofing square.

Step 2: Consider the Slope and Complexity of Your Roof

Once you have determined your home’s footprint, the next step is to consider the slope and complexity of your roof. The slope, or pitch, of your roof affects the total square footage because it increases the surface area that needs to be covered.

The slope of a roof is measured as a ratio of the vertical rise to the horizontal run. For example, a 4/12 slope means the roof rises 4 inches for every 12 inches of horizontal run. Roofs with steeper slopes have more surface area than flat roofs of the same footprint.

Different roof types will affect your calculations as well. Here are some examples:

Gable Roofs: These are simple, up-and-over roofs. To calculate the roofing square for a gable roof, you multiply the home’s footprint by a factor that accounts for the slope. For example, if your home’s footprint is 1,200 square feet and the roof slope is 4/12, you might multiply by 1.1, resulting in 1,320 square feet of roof area.

Hip Roofs: These roofs have slopes on all four sides. They are more complex than gable roofs. If you have a low-slope hip roof, you might use a multiplier of 1.2 or 1.3. So, for the same 1,200 square foot footprint, the roof area might be 1,440 square feet.

Complex Roofs: These include roofs with multiple peaks, valleys, or varying slopes. The complexity requires a higher multiplier. For instance, a steep, complex roof might require a factor of 1.5 or more. For a 1,200 square foot footprint, this would equate to 1,800 square feet of roof area.

By understanding the slope and complexity of your roof, you can more accurately calculate the total roofing square footage. This step is crucial for ensuring you buy the correct amount of materials and plan your project effectively.

Step 3: Calculate the Total Square Footage

After determining your home’s footprint and considering the slope and complexity of your roof, it’s time to calculate the total square footage. This final step combines the information from the previous steps to give you an accurate measurement of your roof area in roofing squares.

To calculate the total square footage, multiply your home’s footprint by the appropriate slope factor. 

  • For example, if your home’s footprint is 1,200 square feet and you have a simple gable roof with a 4/12 slope, you might use a factor of 1.1. The calculation would be:

1,200 square feet (footprint) x 1.1 (slope factor) = 1,320 square feet of roof area.

  • For a hip roof with a low slope, using a factor of 1.3, the calculation would be:

1,200 square feet (footprint) x 1.3 (slope factor) = 1,560 square feet of roof area.

  • For a steep and complex roof, you might use a factor of 1.5. The calculation would be:

1,200 square feet (footprint) x 1.5 (slope factor) = 1,800 square feet of roof area.

These examples illustrate how different roof types and slopes affect the total square footage. Remember, the final number you get represents the roof area, which can then be divided by 100 to determine the number of roofing squares. For instance, a 1,320 square foot roof would equal 13.2 roofing squares.

While these methods provide a good estimate, professional measurement by a roofing contractor is the most accurate way to determine your roof’s square footage. They use specialised tools and techniques to ensure precise measurements, helping you avoid any costly mistakes in your roofing project.

Factors Beyond Roofing Square Affecting Costs

While knowing your roofing square is crucial, other factors also impact the total cost of your roofing project. The type of materials you choose can significantly influence the price. For example, slate tiles are more expensive than asphalt shingles.

Labour costs vary depending on the complexity of the roof. A steep or intricate roof design requires more time and skilled labour, increasing the overall cost. Additionally, the condition of your existing roof can affect expenses. If there’s damage or underlying structural issues, repairs will add to the total cost.


Understanding what a roofing square is and how to calculate it is essential for any roofing project. This knowledge helps in planning, budgeting, and ensuring you have the right materials. For precise measurements and expert advice, contact My Slate Roofing for a professional quote. As experts in the field, we ensure your roofing project is accurate and stress-free. Reach out to us today!

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