When it comes to roofing, the materials used play a critical role in its strength and durability. If you’re planning a roofing project and wondering how much steel is required for a 100 square foot roof, you’ve come to the right place.

In this blog, we’ll keep it straightforward, using examples and everyday language to help you understand the steel requirements for your roofing needs.

1. Steel in Roofing: The Backbone

Before we dive into the calculations, let’s grasp the importance of steel in roofing. Steel is like the sturdy backbone of your roof’s structure, providing the necessary support to withstand the elements.

2. Thickness Matters: Gauge and Steel Thickness

The thickness of the steel used in roofing is crucial. It’s typically measured in gauges, with lower gauge numbers indicating thicker steel. Common gauges for roofing range from 22 to 29, with 22-gauge steel being thicker and stronger than 29-gauge steel.

3. Calculating Steel Requirements: A Simple Formula

To determine how much steel is needed for a 100 square foot roof, we’ll need to consider the gauge (thickness) of the steel and the area to be covered. Here’s a simple formula:

  • Weight of Steel (in kg) = Area (in square feet) x Steel Thickness (in inches) x Steel Density (in kg per cubic inch)

4. Example Calculation:

Let’s use a common gauge for roofing, 24 gauge steel. The thickness of 24-gauge steel is approximately 0.024 inches.

  • Area to be Covered (in square feet) = 100 sq ft
  • Steel Thickness (in inches) = 0.024 inches
  • Steel Density (in kg per cubic inch) = Steel density varies, but it’s roughly around 0.284 lb/in³, which is approximately 0.0096 kg/in³.

Now, let’s calculate the weight of steel required for a 100 square foot roof:

  • Weight of Steel (in kg) = 100 sq ft x 0.024 inches x 0.0096 kg/in³ ≈ 0.02304 kg

So, approximately 0.02304 kilograms of steel are required for a 100 square foot roof using 24-gauge steel.


Understanding the steel requirements for your roofing project is essential to ensure the strength and durability of your roof. Steel acts as the solid framework, ensuring your roof can withstand the elements and protect your home.


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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