After an autumn windstorm, the shingles found on the lawn usually come from the same places: the bottom edge of the roof, the gable ends and the corners. That is not a coincidence. Those edges take the strongest wind uplift, and the first line of defence there is a course most homeowners never see: the starter shingles. Installed under the first visible row, starter shingles seal the leading edge of the roof, fill the gaps behind the first course and give wind nothing to grab. When they are missing, cut wrong or nailed in the wrong place, the edge is where the roof fails first. This guide explains what a starter course does, how roofers install it and what to ask about it before a re-roof.
What starter shingles do at the roof edge
Asphalt shingles are designed to overlap, so each course covers the nails and joints of the one below it. The first course has nothing below it, which leaves two weaknesses that starter shingles exist to fix.
The first course has no sealant bond at its edge. On every other course, the sealant strip on the shingle below bonds to the underside of the shingle above, holding its lower edge down. The first course would have no such bond without a starter strip underneath it. Wind getting under that edge can lift the entire row, and once one row lifts, the next row up loses its support.
Gaps and cutouts would sit directly over the underlayment. Three-tab shingles have cutouts between tabs, and laminated shingles have joints between pieces. On upper courses, those openings sit over the shingle below. On the first course, without starter shingles, they would sit over the underlayment alone, which is not meant to be the roof’s water-shedding surface.
A starter course solves both problems: it puts a continuous layer of shingle material under the first course and places a line of sealant right where the first course needs it. It is small in cost relative to a complete roof replacement, but it does a lot of the edge’s work.
Purpose-made starter strips vs cut 3-tab shingles
There are two common ways to create a starter course, and one method that should be avoided.
Purpose-made starter strip shingles
Most major shingle manufacturers sell dedicated starter strip shingles designed to match their field shingles. They come in long strips, often perforated so they can be split, with a sealant line positioned to sit near the eave or rake edge where it can bond to the first course. Because they are made for the job, the sealant placement and width are consistent, and they are quick to install straight.
Cut 3-tab shingles
The traditional method is to take standard three-tab shingles, cut off the tabs, and install the remaining strip along the edge with its sealant positioned correctly. Done carefully, this works, and it was the norm for decades. The risks are in the details: the cut has to be straight, the sealant has to end up in the right place near the edge, and the joints have to be offset from the first course. Install a cut strip upside down or backwards and the sealant ends up far from the edge, which defeats its purpose.
Laminated shingles used as starter
Laminated, or architectural, shingles have a thick, uneven bottom profile and their sealant sits where it suits a field course, not a starter course. Using them as starter creates a lumpy first course and a poorly placed bond. Shingle manufacturers generally say not to use laminated shingles as a starter, so a crew doing this is working against the product instructions.
| Starter method | Sealant position | Strengths | Risks |
|---|---|---|---|
| Purpose-made starter strip | Factory placed near the edge | Consistent, fast, matched to the shingle system | Still has to be aligned and nailed correctly |
| Cut 3-tab shingle | Depends on how the strip is cut and oriented | Workable when done carefully | Sealant can end up in the wrong place, uneven cuts |
| Laminated shingle as starter | Not designed for starter use | None worth the risk | Uneven first course, poor edge bond, against typical manufacturer instructions |
| No starter at all | None under the first course | None | Exposed joints over underlayment, unsealed first course, high blow-off risk |
Where starter shingles go: eaves and rakes
Along the eaves
The eave starter runs the full length of every lower roof edge. It is laid with a small overhang beyond the drip edge, as specified by the shingle manufacturer, so water drips off cleanly into the eavestrough instead of curling back onto the fascia. The first starter piece is usually trimmed so that its joints fall well away from the joints of the first course, preventing a straight path for water through both layers.
Along the rakes
The rakes are the sloped edges at a gable end. Many roofs were historically shingled without any starter along the rakes, with the cut ends of field shingles simply overhanging the edge. The problem is that rake edges take strong wind, and the cut ends of shingles there have no sealant beneath them. Running a starter course up each rake gives those ends something to bond to. Many shingle manufacturers now require or recommend rake starter, particularly where enhanced wind coverage is offered, so it is worth checking their current installation instructions.
On hip roofs, there are no rakes in the gable sense, so the starter runs along every eave. The hips and ridge are covered later with cap shingles.
The sealant line and why its position matters
Every starter strip has one job above all others: to put adhesive exactly where the first course’s lower edge sits. That is why the sealant on purpose-made starter shingles is positioned close to the edge, and why a cut 3-tab strip must be installed so its sealant ends up there too.
Sealant on asphalt shingles is heat activated. It softens in warm sun and bonds the shingle above. In late autumn, with cooler days and weaker sun, it can take longer for a new roof to seal, and some shingles installed late in the season may not fully bond until warmer weather. Manufacturers describe hand-sealing methods for cold conditions and windy locations, using small dabs of compatible asphalt roofing cement. A careful crew follows those instructions at the edges, where uplift is strongest, rather than relying on spring sunshine to finish the job.
Nail placement interacts with the sealant too. Starter strips are nailed so the fasteners will be covered by the first course and kept clear of the sealant line, following the manufacturer’s diagram. Nails through the sealant strip, or too close to the edge, can crack the strip or leave fastener heads exposed.
How starter shingles work with drip edge and ice and water shield
The edge of a well-built roof is a layered system, and the starter course is only one layer. From the deck up, a typical Ontario eave includes:
- Drip edge: a formed metal strip along the eave that directs water into the eavestrough and protects the edge of the deck and fascia.
- Eave protection: the Ontario Building Code generally requires eave protection on shingled roofs to guard against water backing up behind ice dams, and today it is most often provided with a self-adhered ice and water membrane. Confirm the current extent required for your home with your municipality and the shingle manufacturer.
- Starter course: laid over the membrane, with its overhang past the drip edge.
- First course of field shingles: laid directly over the starter, flush with its lower edge, and bonded by the starter’s sealant.
At the rakes, drip edge is usually installed over the underlayment so water running sideways cannot get behind it, with the rake starter then laid along the edge. The exact order of drip edge and membranes varies with the manufacturer’s details and local practice, so the roofer follows the instructions for the specific products being used.
The point for homeowners is that these layers are designed to work together. A starter course laid over a missing or damaged drip edge, or a membrane that stops short of the edge, leaves a weakness that a perfect starter strip cannot fix. This is also why leaves and ice matter here: eavestroughs packed with autumn leaves back water up against the edge, and in winter that same edge is where ice dams form.
| Edge layer | Eave | Rake | What goes wrong when it is missed |
|---|---|---|---|
| Drip edge | Along the fascia, directing water to the eavestrough | Along the gable edge | Water wicks onto fascia and deck edge, rot over time |
| Ice and water shield | The usual way required eave protection is provided | Sometimes extended in exposed locations | Water from ice dams or backed-up eavestroughs reaches the deck |
| Starter course | Full length, joints offset from first course | Recommended or required by many manufacturers | Unsealed first course, blow-offs, exposed joints |
| First course | Flush with starter edge | Ends bonded to rake starter | Lifting tabs, wind getting under the roof edge |
Why roof edges blow off first in autumn windstorms
When wind flows over a house, it speeds up and separates at the eaves, rakes and corners, creating suction that pulls upward on the roof surface. That uplift is strongest at the edges and especially at the corners where two edges meet. The middle of a slope sees less of it. Roof designers and shingle manufacturers recognise these edge and corner zones, which is why so many detailed requirements focus on them.
Several factors make edge failures more likely in the autumn:
- Older sealant: on an ageing roof, the sealant bond can weaken, and edge shingles that were well bonded years ago may have let go.
- Late-season installs: shingles installed in cool weather may not have sealed fully before the first big blow.
- Missing or incorrect starter: with no bond under the first course or along the rakes, the edges have nothing holding them down except nails.
- High nailing: nails placed above the manufacturer’s nailing zone hold the shingle by less material, and edges release more easily.
From inside the house, the first signs of an edge problem are often indirect: pieces of shingle or starter strip found in the yard after a storm, water stains high on exterior walls or in closets under the eaves, or drips near the top of a window after wind-driven rain. Those are reasons to call a professional, who can check the edges and make roof repairs before winter.
Common starter course mistakes roofers watch for
Starter shingles are hidden once the roof is done, which makes mistakes easy to miss and hard to find later. These are the problems that experienced crews check for during installation:
| Mistake | Why it happens | Likely result |
|---|---|---|
| Starter omitted at rakes | Habit, or treating rake starter as optional | Gable-end shingles lift in strong wind |
| Cut 3-tab installed with sealant away from edge | Strip flipped or rotated incorrectly | First course edge unsealed despite a starter being present |
| Starter joints lined up with first-course joints | No offset trimmed at the start of the run | Direct water path through both layers |
| Too much or too little overhang | Not following the manufacturer’s measurement | Edges sag and crack, or water curls back onto fascia |
| Laminated shingles used as starter | Using leftover field shingles to save material | Uneven first course and a poor edge bond |
| Nails through the sealant line | Rushed nailing without a guide | Weakened bond and possible exposed fasteners |
Manufacturer requirements, in general terms
Every shingle manufacturer publishes installation instructions, usually printed on the bundle wrapper and available in more detail in their technical documents. Those instructions generally cover starter placement at the eaves, overhang, nailing positions and, increasingly, rake starter. Many manufacturers also offer enhanced or system-based warranties that depend on using their matching accessories, which can include their own starter strips, ridge caps and underlayments, and on installation by a contractor they have credentialed.
Warranty terms vary widely between brands and products and change over time, so the only reliable source is the manufacturer’s current documentation. When comparing quotes, ask each contractor which starter they plan to use, whether it will run along both the eaves and the rakes, and whether their installation meets the manufacturer’s requirements for the warranty being offered.
Starter shingles: common questions
Are starter shingles really necessary?
Can a roofer use cut 3-tab shingles instead of a starter strip?
Do starter shingles go on the rakes as well as the eaves?
Why do my roof edges lose shingles in autumn storms?
Can laminated shingles be used as a starter course?
How do I know if my roof has a proper starter course?
Get your roof edges built right with proper starter shingles
The edge of the roof is where wind attacks first, and it deserves the most careful work. When you compare quotes, ask each contractor to describe the starter course at the eaves and rakes and how it is layered with drip edge and eave membrane under the manufacturer’s instructions. If you have lost edge shingles in a storm or are planning a replacement, The Roof Technician can explain what your roof edges need.
Call us today at (416) 826-0040 or request a free estimate.
Building stronger roof edges across Toronto and the GTA.