Our “Quick and Dirty” Guide to Estimate Roofing Materials

Part of the process for getting a new roof is building the budget to see how much it will cost you. If you’ve read our previous article on roof prices, then you already know that material is about 40% of the final cost. That includes underlayment, flashing, fasteners, nails, starter strips, and ridge caps.

So how do you determine the amount of material needed to complete the job? Here’s our “quick and dirty” guide on how to estimate roofing materials for your roof replacement.

Size Matters

Big rooves take more material: that math is really straightforward. So multiply the length of your home by its width.

If you’re only having a portion of your roof repaired, then you don’t need to account for the entire square footage. Instead, double-check with your roof inspector how big the damaged area is, and estimate off that number.

Style Matters

A completely level rooftop–on, say, a manufactured, modular, or mobile home–can be protected by sheets of TPO or EPDM roofing. At $4 to $10 per square foot, these options are much cheaper than multi-layer commercial roofing systems like modified bitumen.

Once you start adding hip rooves, angles, and architectural features like dormers, you’ll likely need more robust materials, like the classic asphalt shingle. 

To account for angles, take the square footage of your home and add roughly 15-20% for roof overhangs and slope. 

Slope Matters

Steep rooves not only require extra safety equipment to install, but they also increase in surface area despite having tiny footprints. (Imagine the typical ski chalet with its iconic A-frame construction.)

The entire pitch of that roof needs to be covered, whether in shingles or shakes or metal roofing. So account for that by multiplying the last number you calculated by a slope factor of 1.1 to 1.4. (This range is typical for most homes.)

“Let’s do the math”

Say you have a 1,700 square foot home. Add 255 square feet for that extra 15% of overhangs, then multiply by a slope of 1.3. That means you’ll need about 2,541 square feet of roofing materials. If you’ve chosen asphalt shingles at $5.75 per square foot, your initial estimate is looking like $14, 613.62.

Feeling too much like a story math problem? That’s the beauty of hiring professionals. At Ideal Roofing Inc. we can provide you with a highly accurate estimate based on your choice of roofing materials.

Save yourself time and energy so you can come back next week and learn how long a roof replacement takes.