If you’re a homeowner or a DIY enthusiast considering taking on the task of re-shingling your roof,you’ve come to the right place. Accurately measuring your roof is a critical first step in ensuring that you:

Purchase the right amount of materials
Avoid unnecessary costs
Prevent delays

We’ll walk you through how to measure a roof for shingles step-by-step, providing you with the knowledge and confidence to get the job done right.

Why Accurate Roof Measurement Matters

Before we get into the nitty-gritty of measuring your roof, let’s understand why accuracy is crucial:

Cost Efficiency: Buying the right amount of shingles ensures you don’t overspend on materials you won’t use.
Time-Saving: Accurate measurements help avoid project delays caused by running out of shingles mid-job.
Waste Reduction: Minimizing waste is both environmentally responsible and cost-effective.

Now, let’s get started!

Tools and Materials You’ll Need

Having the right tools on hand will make the measurement process smoother and more accurate. Here’s what you’ll need:

Measuring tape (preferably 100 feet)
Ladder (ensure it’s stable and long enough to reach your roof safely)
Safety harness and fall protection equipment
Notepad and pen
Calculator
Chalk line or marking paint
Long level or straight edge
Drone with a camera (optional but useful for complex roofs)

Safety First

Before climbing onto your roof, consider these essential safety tips:

Check the Weather: Ensure conditions are dry and sunny. Wet roofs are slippery and dangerous.
Dress Appropriately: Wear non-slip shoes and comfortable clothing.
Use a Stable Ladder: Secure it on a flat, solid surface.
Employ a Safety Harness: Fall protection can be a lifesaver.

7 Steps for Roof Measurement

Ready to get accurate roof measurements? Follow these steps for perfect results.

Step 1: Measure the Base of Your House

Start by measuring the length and width of your house at ground level. This provides a foundational measurement that will guide your calculations. Walk around the perimeter of your home and record these dimensions in feet.

Step 2: Identify Roof Sections and Pitch

Roofs are rarely simple rectangles. They often have multiple sections, each with its own pitch (slope). Identifying these sections is crucial for accurate measurement.

Step 3: Calculate the Pitch of Your Roof

Pitch is the slope of your roof and is typically expressed as a ratio of vertical rise to horizontal run. Here’s how to measure it:

Place one end of your level against the roof’s surface.
Hold the level horizontally and measure out 12 inches (one foot).
Measure the vertical distance from the level to the roof’s surface at the 12-inch mark.
Record this vertical distance as the rise.

For example, if the rise is 6 inches for a 12-inch run, your pitch is 6/12. This ratio will be used in your calculations.

Step 4: Measure Each Roof Section

Now that you have your base dimensions and pitch, it’s time to measure each roof section.

Rectangular Sections:

Measure the length and width of each rectangular section.
Multiply the length and width to get the area.

Triangular Sections:

Measure the base and height of the triangle.
Use the formula (Base x Height) / 2 to get the area.

Irregular Sections:

Break down irregular sections into smaller, manageable shapes (rectangles and triangles).
Measure each smaller shape and calculate their areas.
Add up the areas to get the total section area.

Step 5: Calculate the Total Roof Area

Add the areas of all roof sections to get the total roof area. Remember to account for pitch in your calculations. Use the following formula to adjust for pitch:

First, take measurements for the run of your roof. This is the horizontal length that spans between the peak of your roof and the wall. You can do this with a tape measure or spirit level.
Next, you will figure out the rise. This is the height of your apex above the structure wall.
Now, divide the rise by the run. This will give you the tangent of the roof. (rise ÷ run = tangent)
Then, use the arctan function on your calculator (tan-1), or simply type arctan (*tangent*) into google.
Finally, multiply this result by 180/π and you’ve calculated your roof pitch!

Step 6: Account for Waste

When purchasing shingles, it’s essential to account for waste due to cutting, mistakes, and starter strips. A common practice is to add 10-15% to your total adjusted area.

Step 7: Shingles Packaging and Coverage

Shingles are usually sold in bundles, with three bundles equating to approximately 100 square feet (a square). Therefore, if you need 1,848 square feet of shingles:

You would need to purchase 19 squares (round up to the nearest whole number).

Common Roof Types and Their Measurements

Different roof types may require slightly different approaches to measurement:

Gable Roof

The gable roof is straightforward to measure due to its two rectangular sections. Follow the steps outlined above for rectangular sections.

Hip Roof

Hip roofs have four sloping sides. Break the roof down into smaller sections (triangles and rectangles) and measure each section accurately.

Mansard Roof

A mansard roof has two slopes on each of its four sides. Measure the lower, steeper slopes and the upper, flatter sections separately, then add them together.

Gambrel Roof

Similar to a mansard roof, a gambrel roof has two different slopes. Measure each slope section independently and then sum the areas.

Complex Roofs

For roofs with many valleys and peaks, consider using a drone to capture aerial images. Software can help generate accurate measurements and reduce potential errors.

Tips for Measuring Your Roof

Double-Check Your Measurements: Accuracy is key. Double-check all measurements to avoid costly mistakes.
Use Technology: A roofing calculator app can simplify the math involved in pitch and area adjustments.
Consult Professionals: If you’re unsure about your measurements, consult a roofing professional to verify your calculations.

Leave The Math To Your Roofing Contractor

Measuring your roof accurately is an essential step in any re-shingling project. By following the steps in this guide, you can confidently determine the amount of shingles you’ll need, helping you save time, money, and effort.

If you’re ready to start your roofing project, but want a helping hand, Trust Roofing is only a phone call away! Leave your roofing materials and measurements to us, for a result you can count on, every single time!

How to Measure a Roof for Shingles (7 Step Homeowner’s Guide)