Is there any type of composition shingle the Shingle Gauge™ cannot measure?
Yes. Composition shingles manufactured with “polymer-modified” asphalt do not conform to the Shingle Gauge™. “Modified” asphalt has plastic or rubber added, and changes the thickness of a shingle. You can identify a shingle with modified asphalt by the rubbery or springy feel, rather than the rigid, brittle feel of asphalt.