When shingles start peeling off a roof in a windstorm, the failure almost always begins at the bottom edge — and the bottom edge is exactly what a roofing starter strip exists to protect. This narrow first course, installed before the field shingles, does two unglamorous but critical jobs: it waterproofs the cutout gaps and joints of the first visible course, and it glues that course down against wind uplift with a factory adhesive bead placed right at the eave. Skipping it, or improvising it badly, is one of the most common shortcuts found on failed roofs — and one of the first things manufacturers look for when they deny a wind warranty claim.
What a Starter Strip Actually Does
Look at a standard shingle course: between tabs (on 3-tabs) and between shingle ends (on architectural laminates) there are joints and cutouts that expose whatever sits beneath. Everywhere else on the roof, the course below covers those gaps. At the eave, there is no course below — without a starter, rain running through first-course joints hits bare underlayment and deck edge, and capillary action pulls water toward the fascia.
The second job matters even more. Wind pressure on a roof concentrates at edges and corners; uplift at the eave can run double the field pressure. Starter strips carry a continuous factory-applied sealant band positioned within an inch or so of the eave edge. The first course bonds to that band along its full length, turning the roof’s most vulnerable edge into its best-glued one. Manufacturer high-wind warranties — the 110 to 130 mph ratings printed on shingle wrappers — are contingent on proper starters at eaves, and usually rakes too.
Factory Starter vs. Cut-Up 3-Tabs
For decades, roofers made starters in the field by cutting the tabs off 3-tab shingles and installing the remaining headlap strip, sealant band up, along the eave. It worked acceptably when the field shingles were also 3-tabs. It’s a poor match for modern architectural shingles, for three reasons:
- Adhesive position: a 3-tab’s sealant band sits an inch or more up from the butt edge once inverted, leaving the outermost edge of the first course unbonded — exactly where wind grabs first. Purpose-made starters put the bead at the edge.
- Warranty compliance: GAF, Owens Corning, CertainTeed, and IKO all specify their own starter products for enhanced wind coverage. A claims adjuster who finds cut 3-tabs can downgrade or deny.
- Labor: cutting starters wastes 15 to 30 minutes per roof and produces inconsistent widths. Factory starters like GAF Pro-Start, Owens Corning Starter Strip Plus, or CertainTeed SwiftStart come perforated — snap each shingle in half and you get two ready strips.
Cost difference is trivial: factory starter runs $40 to $70 per bundle covering roughly 100 to 120 lineal feet, adding perhaps $100 to $200 to a whole-house job. Against a $12,000 roof, it’s a rounding error that buys the warranty.
Starters at the Rakes: Required or Optional?
Eave starters are universal. Rake (gable edge) starters were once considered optional, but most manufacturers now require them for high-wind coverage, and every roofer in wind country should treat them as standard. A rake starter runs up the sloped edge, sealant band toward the edge, giving the field shingles a bonded, straight-edged substrate. Benefits beyond wind: a crisp sightline to run courses to, and a doubled edge that resists the slow lift-and-crack cycle at gables. In hurricane and tornado states, some enhanced warranty tiers and the IBHS FORTIFIED standard explicitly call for sealed rakes — either rake starters or a hand-sealed edge with asphalt cement.
How to Install Starter Strips Correctly
- Prep the edge. Drip edge goes on the eave first (under the underlayment at eaves per most codes, over it at rakes), then underlayment or ice-and-water shield laps onto it.
- Set the overhang. Snap a chalk line so starters overhang the drip edge 1/4 to 3/8 inch — enough to drip cleanly into the gutter, not so much that edges droop and flutter. Never run shingles flush with the fascia.
- Orient the adhesive. The factory sealant band faces up and toward the eave edge. Installing starters upside down or backwards is the classic Monday-morning error and eliminates the entire bonding function.
- Fasten properly. Four to five nails per strip, 1-1/2 to 3 inches up from the eave edge — low enough to be covered by the first course, high enough to miss the sealant. Use 1-1/4-inch roofing nails minimum into solid deck.
- Offset the joints. Starter joints must not align with first-course joints; maintain at least a 4-inch offset (many specs say 6) so no joint stacks over another.
- Rakes next. Run rake starters from eave to ridge, overlapping the eave starter at the corner, sealant outboard.
In cold weather, the sealant bands won’t activate until the sun warms them; below about 40°F, hand-seal the first course with quarter-size dabs of ASTM D4586 roofing cement under each shingle edge, because a winter windstorm won’t wait for spring thermal bonding.
Starter Strips on Other Roof Systems
The starter concept isn’t unique to asphalt. Metal shingle and stone-coated steel systems use a formed metal starter flashing that hooks the first course. Synthetic slate and shake systems (DaVinci, CeDUR) specify their own starter course pieces. Even cedar roofs use a doubled first course for the same water-shedding logic. On low-slope transitions — porches at 2:12 to 4:12 — starters remain required, riding over the ice-and-water membrane that such slopes demand. The principle is universal: the first course needs something beneath it doing the job a course below would do everywhere else.
Spotting Starter Problems on an Existing Roof
You can audit a roof’s eave detail from a ladder in five minutes. Lift the bottom edge of a first-course shingle gently on a warm day: you should feel continuous adhesive resistance, and beneath the joints you should see shingle material, not underlayment. Red flags include daylight or felt visible through first-course cutouts, first-course edges that lift freely in the breeze, shingles trimmed flush with the fascia, or wavy course lines telegraphing from an unstraight start. Any of these on a recent roof is worth a call back to the installer — and on an older roof, it explains why the eave courses always fail first. Starter strip is a $150 detail that determines whether the other $12,000 stays attached; there is no cheaper insurance anywhere on a roof.
Estimating and Buying Starter
Takeoff math is simple: measure every eave and, if you’re sealing rakes (you should be), every rake as well. A basic gable ranch with a 60-foot ridge and two 30-foot gable ends carries 120 feet of eaves and roughly 68 feet of rakes depending on pitch — call it 190 lineal feet, plus 10 percent for laps, waste, and the corner overlaps. At 100 to 120 feet of coverage per bundle, that’s two bundles, $80 to $140 total. Hip roofs need less rake material (hips take hip-and-ridge caps, not starters) but often have longer total eave runs, so measure rather than assume.
Product choice is less critical than orientation and placement, but a few distinctions help. Match the starter brand to the field shingle when you’re chasing an enhanced warranty — GAF’s tiered warranties, for example, require a specific count of GAF accessory products, and starter is the cheapest qualifying item. For steep-slope architectural roofs in high-wind zones, look for starters with an aggressive sealant band rated to the same wind spec as the shingle (Owens Corning’s Starter Strip Plus and CertainTeed SwiftStart both publish ratings). And check the exposure math: starter strips are typically 6.5 to 7.75 inches wide, sized so the factory adhesive lands under the butt edge of a standard-exposure first course. If your field shingle runs an oversized exposure — some designer profiles do — verify the manufacturer pairs it with a specific starter width, or the bead can end up sitting uselessly uphill of the shingle edge. Five minutes of reading the wrapper at the supply house prevents the one starter mistake that can’t be seen from the ladder afterward.
