What Starter Strip Actually Does
Unlike regular field shingles, starter strip is designed specifically for the roof's edges. It has a continuous strip of adhesive positioned near the eave so that the tabs of the first row of shingles bond securely to it instead of lying loose.
- Seals the first course: The adhesive grabs the bottom edge of the first shingle row, eliminating the gap where wind could otherwise lift shingles.
- Covers the cutouts: Starter strip backs the keyways (slots between shingle tabs), so water can't slip through the joints of the first row.
- Defines a clean edge: It gives the eave and rake a straight, finished line and proper overhang for water to shed into the gutter.
Why Starter Strip Matters in the Inland Northwest
Around Spokane, Colbert, and North Idaho, the roof edge takes the worst of our weather, which makes a properly installed starter strip more than a formality.
- Wind uplift: Gusts hit the eaves and rakes hardest. Without a bonded starter strip, wind can peel the first row of shingles back and cascade damage across the roof.
- Ice dams: Eaves are exactly where ice dams form during our freeze-thaw cycles. A sealed starter course works alongside ice-and-water shield to keep meltwater from backing up under the shingles.
- Snow load and runoff: Heavy snow sliding off the roof concentrates stress and moisture at the edge. A solid starter strip keeps that perimeter watertight all season.
Common Starter Strip Mistakes
Because it's hidden under the first row, starter strip is an easy place for a rushed crew to cut corners. We see a few recurring problems on inspections.
- Using cut field shingles upside down: Flipping a regular shingle puts the adhesive in the wrong spot, so the first row never bonds properly.
- Skipping the rakes: Some installers only run starter along the eaves and forget the rake edges, leaving the gable ends vulnerable to wind.
- Wrong overhang: Too little overhang lets water wick behind the gutter; too much makes the edge prone to wind damage.
Proper starter strip detailing is part of every roof replacement we install as a GAF Master Elite contractor.