All of these shapes are a square
All of these shapes are a square
"When it comes to roofing, it is function over form, with attention to form."
by Stefan Mach | March 19, 2016 | Roofing terminology
Roofers Are Not Bad Shape Identifiers
So what gives? Basically, a roofer’s use of the term “square” means any area that represents 100 square feet. As a result, any shape that covers this area is considered a square by a roofer. Notice that I did not say all the above shapes were “squares”. This would be of course wrong, and I would need to go back to pre-k. I also did not make the mistake of telling you that a roofer’s square is a 10’x10′ area. This mistake is often made. Of course, a 10’x10′ area is a square, but so is an isosceles triangle ( a triangle with two equal sides and two equal angles) with a base of 20′ and a height of 10′, a parallelogram in which adjacent sides multiplied equal 100 and opposite sides are parallel, and a rectangle in which adjacent sides multiplied equal 100.
The use of the term "square" by roofers in not about the squareness as you usually think of it.

This shape is a square

And this shape is a square

This shape is a square too

So is this one
Summarized, a roofer’s use of the term square has little to do with shape and everything to do with surface area being equal to 100 square feet. A circle can even be a “square” according to this use of the term.
As an aside, roofing shingle manufacturers have what they like to refer to as a “field square”. To learn more about this designation, go to our page, Field Square Defined.
Thanks for reading.