If you’re in the residential roofing business, there’s a little-known secret that can save you time and keep you safe. It’s a simple technique, taught to me by one of my subcontractors, for measuring the size of asphalt shingle roofs without ever leaving the ground. And the best part? It’s highly accurate.
The Shingle Count Method
Let’s start with the “Shingle Count” method, which is perfect for rectangular-shaped sections of a roof. Here’s how it works:
- Each tab on a 3-tab shingle is approximately 12 inches wide and 6 inches high.
- Begin by counting the number of shingles from left to right to determine the total width of the section in feet.
- Count the number of rows of shingles from the gutter to the peak of the roof and divide it by 2 to get the height measurement.
- Multiply the width and height measurements together to get the total square footage of the section.
- Repeat this process for each remaining section.
For triangular-shaped roof sections like dormers, count the shingles from side to side where it’s widest and from the gutter to the peak. Keep in mind that each shingle is approximately 12 inches wide and 6 inches high. Since these sections make up a small percentage of the entire roof, using the resulting number is acceptable, even if it’s slightly larger than the actual measurement.
Estimating Square Footage of Hip Roofs
Hip roofs, which have four sides and resemble a pyramid, require a different technique. Try this simple calculation:
- Measure the length and width of the house.
- Multiply the length and width numbers together.
- Multiply the result by 1.35.
Note that this method may yield a slightly higher square footage number than the actual measurement. However, it’s always better to overestimate the size of a roof job than to underestimate it.
When it comes to taking accurate measurements, having the right tools is essential. I personally use a Canon digital camera with a 10x optical zoom and a 40x digital zoom. This allows me to zoom in closely and capture excellent photos of roof details, such as flashing and the condition of the current roofing materials. Regardless of the camera brand, the most important feature is the size of the zoom, as it enables you to take clear photos while standing on the ground.
Speaking of cameras, another important feature for a digital camera used in property preservation businesses is a flash that provides sufficient light for taking above-average quality photos in complete darkness.
Please note that it’s always a good idea to test these methods before fully relying on them. During your next roofing estimate, compare the square footage you measure directly with the numbers obtained using these two calculations. You’ll likely be surprised at how closely the results align. With this knowledge, you can confidently retire your ladder.
I hope you find these time-saving and helpful techniques as valuable as I have. Remember, safety and accuracy are key when it comes to residential roofing jobs.