How Many Feet Is In A Square Of Shingles

How Many Feet Are in a Square of Shingles? A Comprehensive Guide for Roofing Projects

Choosing the right roofing materials is crucial for any home improvement project. For many, asphalt shingles remain a popular and cost-effective option. But understanding the terminology and calculations involved in purchasing these materials can be confusing. This comprehensive guide will demystify the concept of a "square" of shingles and help you accurately determine how much you need for your roofing project.

Understanding the "Square"

The term "square" in roofing doesn't refer to a geometrical square. Instead, it represents a standard unit of roofing material measurement, equivalent to 100 square feet. This standardized unit simplifies the process of ordering and estimating roofing materials, regardless of the roof's complexity or shape.

Whether you're dealing with asphalt shingles, wood shakes, or other roofing materials, a square consistently means 100 square feet. This consistent measurement ensures clear communication between homeowners, contractors, and suppliers.

Calculating Your Roofing Needs: Beyond the Basics

Calculating the number of squares you need involves more than just measuring the roof's area. Several factors influence the final calculation:

1. Roof Area Calculation:

This is the most fundamental step. Accurately measuring your roof area is essential. Different roof shapes require different calculation methods:

Simple Rectangular or Square Roofs: Measure the length and width of the roof. Multiply the length by the width to obtain the total square footage. Divide this number by 100 to determine the number of squares needed.
Gabled Roofs (with two slopes): Measure the length and width of each slope separately, and add the areas together. Divide the total area by 100.
Hip Roofs (with four slopes): This calculation becomes more complex. It's often best to break the roof down into smaller, manageable sections (like triangles and rectangles) and calculate the area of each section individually. Then, add the areas together and divide by 100.
Complex Roofs: For extremely complex roofs with multiple slopes, valleys, dormers, and other features, it's highly recommended to consult a professional roofing contractor. They possess the expertise and specialized tools to accurately measure and estimate the roofing material requirements. Incorrect calculations can lead to material shortages or excessive waste.

2. Waste Factor:

No matter how precise your measurements, you'll always have some material waste. This waste can be due to cuts, damaged shingles, or simply the natural imperfections in the material. A typical waste factor ranges from 5% to 15%. This means that you should add this percentage to your total square footage calculation to account for potential losses.

For a simple roof, a 5% to 7% waste factor might suffice.
Complex roofs with many cuts and angles might require a waste factor of 10% to 15%.
Experienced contractors might have a better idea of the appropriate waste factor based on past experiences and the type of shingles being used.

3. Overlap:

Asphalt shingles require overlap for proper installation and water resistance. The amount of overlap varies depending on the shingle type and manufacturer's instructions. This overlap affects the effective coverage of each shingle and needs to be considered when calculating your needs. Consult the shingle manufacturer's instructions for specific overlap guidelines. Failing to account for overlap could result in insufficient coverage and potential leaks.

4. Starter Strips and Ridge Caps:

Beyond the main shingle field, you'll need starter strips at the bottom of the roof and ridge caps at the peak. These are sold separately and require additional calculations. Check the manufacturer's specifications for square footage coverage per package of these components.

5. Flashing and Accessories:

Don't forget about flashing (metal pieces installed around chimneys, vents, and valleys) and other accessories. These materials are sold separately and are essential for proper water sealing and long-term roof durability.

Example Calculation: A Simple Rectangular Roof

Let's assume a rectangular roof with a length of 40 feet and a width of 30 feet.

Calculate the total area: 40 feet x 30 feet = 1200 square feet.
Calculate the number of squares: 1200 square feet / 100 square feet/square = 12 squares.
Apply a waste factor: Let's assume a 10% waste factor: 12 squares x 0.10 = 1.2 squares.
Add the waste factor to the total: 12 squares + 1.2 squares = 13.2 squares.
Round up to the nearest whole number: You would need to purchase 14 squares of shingles to account for the waste.

Important Note: Always round up to the nearest whole number when calculating the number of squares needed. It's better to have a little extra material than to run short during installation.

Different Shingle Types and Their Coverage

The number of shingles per square varies depending on the shingle type and manufacturer. Three-tab shingles typically have a different coverage per square compared to architectural shingles (also known as dimensional shingles). This is due to their different sizes and designs. Always refer to the manufacturer's specifications for the exact shingle coverage.

Three-Tab Shingles: These are a cost-effective option, generally covering around 100 square feet per square.
Architectural Shingles: These offer a thicker, more durable, and aesthetically pleasing option. However, they typically use slightly more material per square foot due to their thicker profile and layered design. They might have slightly less coverage per square than three-tab shingles.
Luxury Shingles: Premium options have even greater thickness and design complexity, and their coverage per square can vary.

Always check the package labeling or consult the manufacturer's documentation for precise coverage information. This ensures accurate ordering and minimizes potential shortages.

Working with a Roofing Contractor: The Expert Approach

While calculating the square footage yourself can be helpful, engaging a qualified roofing contractor brings several advantages:

Accurate Measurements: Contractors have the experience and tools to accurately measure even complex roofs, minimizing potential errors in material estimation.
Material Expertise: They can advise on the best shingle type and quantity, considering your roof's features, climate, and budget.
Waste Minimization: Their expertise can minimize waste, saving you money in the long run.
Professional Installation: They will ensure proper installation, maximizing the lifespan of your new roof and protecting your investment.

Getting multiple quotes from reputable contractors allows for comparison and ensures you get the best value for your money.

Conclusion: A Solid Foundation for Your Roofing Project

Understanding the concept of a "square" of shingles is fundamental to successful roofing projects. By accurately calculating your roof's area, considering waste factors, and understanding shingle coverage, you can effectively estimate the necessary materials. Remember to consult the shingle manufacturer's specifications, account for overlap, and consider additional materials like starter strips and ridge caps. For complex roofs, involving a professional roofing contractor provides peace of mind and minimizes risks. Planning thoroughly before you begin your roofing project will ensure a smooth and successful outcome. Remember, accuracy in measurements and material selection is crucial for a lasting and leak-free roof.