From The Ground Up: Measure a Roof

April 16, 2018

People are sometimes skeptical or perplexed when I come to measure a roof, and I don’t actually get UP ON their home’s roof.

I do perform a thorough roof inspection and sometimes I need to raise a ladder and climb onto the roof to see and problem-solve a hidden or complicated area. But for the most part, I measure from the ground.

Here’s How I Measure a Roof

First I make a drawing of the roof from a bird’s-eye view, which requires a full walk-around. Next,  I get out my measuring wheel and measure every perimeter on the ground, including the overhangs. I usually need to get on a ladder at this point to check the pitch angle of the roof with a pitch gauge. This allows me to see the roof close up and determine how many layers might be there, and look at the gutter, drip edge, etc.

Back inside, I figure the roof area by breaking the roof down into sections. For each section, I apply two multipliers: one based on the pitch of the roof and one for the complexity of that area. This method has proven very accurate for me over the years.

The Story of a Tough One

I recall one measure in particular, just a couple years after we opened this office. I arrived at a house in the “horse country” of the Lawrenceburg or Versailles areas.  As I pulled into the driveway, my jaw dropped a little. I have seen plenty of large and complicated roofs but this one was a doozy! It was steep, non-walkable, and very cut-up with lots of odd angles and wings going off in all directions. The homeowner was sitting there on his lawn tractor and, seeing my reaction he chuckled a little bit. “Yeah I warned you over the phone, it’s a tough one!” he said.

He then proceeded to tell me “I usually get up onto the garage and from there I can get up onto the main roof…” and I told him no;  I’m going to get all my measurements from the ground. “Well, okay,” he said, “but I should warn you that your competition was here earlier today and they had two men crawl all over that roof for an hour getting measurements.”

I grinned and asked, “What did they come up with?” “Oh no!” he said, “You tell me your number first!”

I got about my business, made my drawing, did my ground measurements and then sat down at his kitchen table and worked out my sections and multipliers.

“Fifty-seven squares!” I told him. He looked shocked. “Wow, they came up with 59.” He was impressed that our numbers were so close using very different methods; mine being much quicker and safer of course! I think that roof was so complex, many roofers would have rounded up to 60 just to be safe. But I was comfortable quoting at 57 and again very happy to be that close mathematically to someone who had done tedious hand-measurements on the roof.

I had confidence in my methodology before that—it’s widely used and trusted in our industry—but that measure proved to me that it’s the right way to go. Or perhaps the right way to stay: on the ground.