How Many Shingles Will My Roof Need? Roofing Squares Explained

If you're planning a roof replacement project, one of the first steps is calculating how many shingles and other materials you'll need. This is where the concept of "roofing squares" comes in handy. Roofing squares provide a simple way to estimate the shingles and accessories required to complete your roofing job.

We'll also discuss the benefits of thinking in squares rather than individual shingles when planning a roofing project.

What is a Roofing Square?

A "roofing square" refers to 100 square feet of roof area. It's a standard unit of measurement used throughout the roofing industry to estimate materials and simplify pricing. The concept dates back over a century, providing a consistent system for roofers, contractors, and homeowners.

Instead of having to calculate individual shingles and materials by the square foot or yard, roofing squares allow everything to be estimated based on bundles per square. This makes planning and ordering much more straightforward!

Calculating Total Roofing Squares

To determine the number of squares on your roof, you'll first need to calculate the total square footage. This involves carefully measuring the length and width of each roof section and multiplying to find the area.

For example, if you have a simple rectangular roof that's 40 feet long by 30 feet wide, the area would be 40 x 30 = 1200 sq ft. To convert to squares, simply divide the total square footage by 100. So in this case, 1200 sq ft / 100 = 12 roofing squares.

For homes with more complex rooflines involving multiple sections, dormers, and angles, you'll need to break the roof into segments and calculate each area individually. Then add up all the sections to get the total roofing squares.

Tips for Measuring Roof Area

• Use a measuring tape for dimensions or satellite views for estimation
• Account for all sections - don't miss dormers or angles
• For steep roofs, multiply length by average width rather than peak
• Have a roofer or contractor confirm your DIY measurements

Ordering Roofing Materials by the Square

Once you know the number of squares, it becomes easy to estimate the required materials. Roofing manufacturers size their shingle bundles and packages to cover one square when installed.

So if your roof is 35 squares, you would need approximately 35 bundles of each type of shingle as well as 35 squares of underlayment, flashing, ridge caps, etc. Any variation can be adjusted as you get into the specifics of each material.

Shingle Quantity by the Square

Most asphalt shingle bundles will cover around 33-35 sq ft when installed on the roof. This equals about 3 bundles per square. So for a 15 square roof, you'd need about 45 bundles of shingles.

Concrete or clay tiles may cover 5-8 sq ft each, requiring 12-20 tiles per square. Metal shingles also have their own coverage ratios based on panel size - be sure to check manufacturer specs.

Roofing Squares and Layout

Roofing squares are not only useful for estimating materials - they also help contractors plan installation layouts and workflow. By breaking the roof into square sections, crews can work efficiently from top to bottom.

During tear-off, they may remove one square at a time. Then install each layer - underlayment, ice shield, shingles - one square section after another. This helps ensure proper alignment and simplifies staging of materials on the roof.

Tips for Layout

• Mark roof squares on your plan for reference
• Start with a straight and level starter row
• Use chalklines between squares for neat courses
• Stage only 1-2 squares of materials at a time

Cost Per Square for Roofing

When getting estimates from contractors, you'll often see "cost per square" as a benchmark for comparing quotes. This allows you to calculate a total price based on the number of squares needed.

On average, professional installation costs range from $250-500 per square including both labor and materials. Simple, low-pitch roofs on the low end and complex roofs with premium materials on the high end.

Factors Affecting Price Per Square

• Roof pitch - low is cheaper than steep
• Accessibility - height and ease of reach
• Regional labor rates - higher in some areas
• Type of shingles - from asphalt to tile and metal

Estimating Layer Materials by the Square

It's not just shingles that get estimated by the roofing square. All other layer materials like underlayment, ice shield membrane, drip edge, and flashing should also match your total roofing squares.

As a rule of thumb, allow 1 square of each product for every square of shingles. It's also smart to add 10-15% overage to account for waste, customization, and repairs down the road.

Typical Layer Materials Per Square

• 1 square underlayment
• 1 square ice/water shield
• 1 square drip edge
• 1 square flashing

Benefits of Ordering Roofing Squares

Thinking in squares may take some getting used to, but it offers many advantages over estimating individual shingles or tiles.

Squares provide a convenient shorthand to determine the right quantities of materials for the full roof area. They also allow easy price comparison between material brands and contractor bids.

Overall, roofing squares are an indispensable tool for both homeowners and professionals to accurately plan, budget, and execute a successful, cost-effective roofing project.

Key Benefits of the Roofing Square Method

• Simplifies material quantity estimates
• Allows apples-to-apples price comparisons
• Eliminates guesswork and errors
• Sets an industry-wide standard

FAQs About Roofing Squares

Here are answers to some frequently asked questions homeowners have about roofing squares:

• What is the actual size of a roofing square? A roofing square equals 100 square feet of roof area.
• How many shingle bundles are needed per square? About 3 bundles of asphalt shingles cover 1 roofing square.
• Do I need to order a full square of underlayment? Yes, it's recommended to match squares of underlayment to shingles.
• Does a square include overhangs and eaves? No, only the main roof surface area counts towards squares.
• How accurate do my measurements need to be? Within 5-10% is okay - contractors will inspect and finalize.