What Is Starter Strip?
The starter strip runs beneath the first visible shingle course along eaves and rakes, doing two quiet jobs: its solid surface backs the cutouts and joints of the course above so water passing between shingle edges lands on asphalt instead of underlayment, and its continuous factory sealant bead bonds the overlying shingles' bottom edge down. That bond is the roof's primary wind defense at its most wind-loaded location — uplift pressure peaks at edges and corners. Roofs fail here when starter is omitted, installed backward with the adhesive uphill, or improvised from inverted field shingles whose sealant line sits inches from the edge. The failure shows up in the first serious windstorm as shingles peeled specifically from eaves and rake lines while the field holds. Homeowners can sometimes check by gently lifting a first-course shingle edge: it should resist, bonded to a strip below. Correction requires removing and re-laying the perimeter courses with proper starter.
Important Distinction
Note: A starter strip is a purpose-made product with its sealant line at the outer edge; cut-up three-tab shingles used as starter place the adhesive in the wrong position, and skipping starter entirely is a leading cause of edge blow-offs.
Also Known As
These are the search terms and phrases that commonly refer to this topic, so you can find it however you describe it.
How Starter Strip Relates to Other Topics
The starter strip carries the sealant bead at the roof's edge - exactly where uplift is strongest; field shingles cut up and used as starter put no sealant there, leaving the most-stressed edge of the roof unglued.
The first course of shingles has cutout joints with nothing under them; the starter strip beneath exists to seal and back those joints - skip it and every first-course joint is a straight path to the underlayment.
The starter course overhangs the drip edge by roughly a quarter to three-quarters of an inch to form the drip line; shingles cut flush with the metal wick water backward onto the fascia instead of dropping it clear.
Related To Starter Strip
Perimeter uplift is why edge details punch above their weight: the starter strip and the first course carry the highest suction loads on the roof, so edge shortcuts fail in winds the field would have survived easily.
Questions about Starter Strip?
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