Should I include roof overhangs and waste in my measurements?

Yes. For accurate material needs, always include the area of roof overhangs and add at least 10% extra for waste, cuts, and complex roof features such as valleys and dormers.

Can I estimate my roof size without climbing on the roof?

While ground measurements can offer a basic footprint estimate, actual roof surface area may be larger due to pitch and architectural features. For best results, rely on direct measurements or professional assessment.

What Is a Roofing Square and How to Calculate It?

By Tony Delco Roofing

When discussing roof repair or replacement with a contractor, the term “roofing square” is frequently used. This measurement is the industry standard for estimating material costs and labor time. Understanding what a roofing square represents helps homeowners accurately compare quotes and understand the scope of their project.

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Defining the Roofing Square

A roofing square is a unit of area measurement used exclusively within the roofing industry.

One roofing square is equal to 100 square feet (10 feet by 10 feet).

Roofing materials, such as shingles and underlayment, are packaged and sold in quantities required to cover one roofing square. By determining the total number of squares your roof requires, a contractor can precisely calculate the amount of materials needed for the job.

How to Calculate Roofing Squares

Calculating the total number of squares your roof requires involves three primary steps: measuring the flat area, factoring in the roof’s slope, and applying the conversion formula.

1. Measure the Roof Area

The first step involves measuring the length and width of each rectangular section of your roof plane. Multiply the length by the width to get the square footage for that section. Add the square footage of all roof sections together to find the roof’s total square footage (TFS).

2. Account for Pitch (Slope Factor)

Flat measurements taken from the ground or eaves do not account for the vertical rise of the roof. The pitch, or slope, increases the actual surface area that materials must cover. Contractors use a multiplier, or “pitch factor,” based on the steepness of the roof.

For example, a low sloped roof might require a pitch factor of 1.05, while a very steep roof may require a factor of 1.30 or higher. Multiplying the TFS by the pitch factor yields the Actual Surface Area (ASA).

3. Apply the Formula

Once the Actual Surface Area is determined, calculating the number of roofing squares is straightforward. The total area is simply divided by 100.

The basic calculation looks like this:

\text{Total Roofing Squares} = \frac{\text{Actual Surface Area (in square feet)}}{100}

For example, if the calculated Actual Surface Area of a roof is 3,200 square feet, the roof requires 32 roofing squares of material.

Common User Questions: Roofing Squares & Your Home

How many bundles of shingles are in a roofing square?

Typically, 3 bundles of asphalt shingles make up one roofing square, though this can vary by shingle design and manufacturer.

Should I include overhangs and waste in my calculations?

Absolutely. Include eaves and overhangs, and add an extra 10% for waste, cuts, and starter shingles, especially if your roof has a lot of valleys, dormers, or intricate shapes.

Can I measure my roof from the ground?

Yes, you can estimate by measuring the house’s footprint for basic calculations, but for accuracy, especially with complex roofs measure each roof surface directly or consult a professional.

roofing calculators — A digital roofing calculator is being used to estimate materials for a new roof.

Why the Roofing Square Matters for Homeowners

Using the roofing square simplifies both the buying process and the installation process.

Accurate Estimates: Having the measurement in squares provides a clear, standardized unit for comparing quotes from different roofing companies. If one contractor quotes 30 squares and another quotes 40 for the same roof, it signals a significant difference in how the measurements were taken, requiring further explanation.
Material Ordering: Materials are rarely purchased by the single shingle or foot. Using the square allows for accurate ordering of shingles, underlayment, and metal flashing materials, minimizing waste and ensuring the right quantity arrives on site.
Labor Quoting: Many contractors quote labor time and cost based on a fixed rate per square, making the total square count directly related to the final project price.

While the calculation is simple, proper measurement and application of the pitch factor require specialized tools and expertise. For an accurate square count and a reliable quote, homeowners should always rely on a professional estimator.

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