When it comes to roofing, understanding the square footage of your roof is crucial for various reasons. However, a common misconception is that the roof’s square footage is the same as the house it covers. In this blog, we’ll explore this misconception, explain why it’s not accurate, and provide you with a clear understanding of how to calculate your roof’s square footage.


Your house and your roof are closely connected, but they are not the same when it comes to square footage. The square footage of your house refers to the total living space inside, while the square footage of your roof is the area it covers on the exterior.

Why Your Roof Isn’t the Same Square Footage as Your House

  1. Overhangs and Eaves: Your roof extends beyond the walls of your house, creating overhangs and eaves. These areas are part of the roof but not part of your living space. Therefore, they add to the roof’s square footage without increasing your house’s square footage.
  2. Pitch and Slope: The angle or pitch of your roof affects its square footage. A steeper roof may have a larger exterior square footage than a flatter roof covering the same house.
  3. Gables and Dormers: Architectural features like gables and dormers increase the complexity of your roof. While they contribute to the roof’s square footage, they don’t necessarily add living space to your house.

Calculating Your Roof’s Square Footage

To find your roof’s square footage accurately, you’ll need to break it down into its basic shapes, calculate each area, and then add them together. Here’s a simplified method:

  1. Divide Your Roof Into Sections: Break your roof down into rectangles, triangles, and other basic shapes.
  2. Calculate Each Section’s Area: Measure the length and width of each section and use the appropriate formula (e.g., area of a rectangle = length x width) to find its square footage.
  3. Add All Section Areas Together: Sum up the square footages of all sections to get your total roof square footage.

Practical Example

Let’s say you have a house with a simple gable roof. You measure the length of the house as 40 feet and the width as 30 feet. The roof has two identical triangular sections on each side. The formula for the area of a triangle is 0.5 x base x height.

  • House Square Footage = 40 feet x 30 feet = 1200 square feet
  • Each Triangular Section = 0.5 x 30 feet x 20 feet = 300 square feet
  • Total Roof Square Footage = House Square Footage + 2 x Triangular Section = 1200 square feet + 2 x 300 square feet = 1800 square feet


Your roof’s square footage is not the same as your house’s square footage due to overhangs, pitch, and architectural features. Understanding the difference is essential for roofing projects, as it affects material calculations and costs.


In the world of roofing, clarity on square footage is vital. While your house’s square footage is about your living space, your roof’s square footage is all about coverage and design. Knowing how to calculate your roof’s square footage accurately ensures you’re well-prepared for roofing projects and helps you avoid misconceptions about your home’s dimensions.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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