What does an architectural shingle look like?
Short answer. A single architectural shingle is a rectangle roughly 13 by 39 inches made of two layers bonded together: a top layer with an irregular, tooth-like lower edge, and a darker bottom strip that shows through the gaps. The upper part has a marked nailing area and a sealant strip, and the lower part is the colorful exposed portion you see on the roof.
The parts of one shingle
- Headlap: the plain upper portion that ends up covered by the next course. It often carries printed text or arrows.
- Nailing zone: a marked band, usually a painted line, printed words or a textured strip, where the two layers overlap. Nails go here so they catch both layers.
- Sealant strip: a line of heat-activated adhesive that bonds the shingle to the one above or below it once the sun warms it.
- Tabs: the exposed lower part of the top layer, cut into random-width teeth so no two shingles repeat exactly.
- Underlay strip: the bottom layer, usually coated in darker granules, which shows through between the tabs and creates the shadow lines.
- Back: sand or mineral coating, plus a plastic release film strip that keeps bundled shingles from sticking together. It stays on during installation.
Size and coverage
Many common architectural shingles measure about 13 1/4 by 39 3/8 inches with roughly 5 5/8 inches exposed on the roof. Bundles typically hold enough to cover a third of a square, so three bundles cover 100 square feet.
Compared with a 3-tab shingle
A 3-tab shingle is a single flat layer, about 12 by 36 inches, with two straight slots cutting it into three equal tabs. Held side by side, the architectural shingle is noticeably thicker and heavier, with an uneven bottom edge and two-tone color.
Color blends
Granules are mixed from several shades so the roof looks varied rather than painted. That is why a single shingle in your hand can look different from the same color on a whole roof.
See architectural vs 3-tab shingles and roof anatomy explained.