What are starter strip shingles?

Starter strip shingles form the bottom edge of a roof, running the full width of the eave line before the first course of standard shingles begins. This specialized course consists of shingles (either cut-down full shingles or commercially manufactured starter strips) installed upside-down so their adhesive side faces outward, creating a solid seal along the perimeter.

The primary role of starter shingles is twofold. They prevent water from being driven under the first regular course of shingles during rain and wind events, blocking one of the most common entry points for leaks. They also provide a nailed anchor for the first row of field shingles, ensuring proper installation geometry and preventing the upper courses from lifting in high winds. Without a proper starter course, the exposed roof edge becomes vulnerable to moisture infiltration along the eave fascia and roof deck.

Starter strip products vary by manufacturer but typically feature the same granulation and color-match options as the corresponding shingle line. Proper installation requires alignment with the eave edge and fascia board, with nails spaced according to manufacturer specifications. This layer is essential on every roof replacement or installation, whether a reroof or new construction.