The adhesive line on asphalt shingles that bonds each shingle to the one below it — a critical component for wind resistance and one of the primary indicators used to determine storm-related damage in roof insurance claims.
Table of Contents
- What a Seal Strip Is
- How Seal Strips Work
- Why Seal Strips Matter
- Seal Strip Failure
- Seal Strips and Wind Damage
- Seal Strips in Insurance Claims
- How Seal Strips Are Tested
- Common Questions
- How Claim Advocacy Helps
- Related Glossary Terms
What a Seal Strip Is
A seal strip is a factory-applied adhesive strip located on asphalt shingles that bonds each shingle to the one beneath it after installation.
Once activated by heat from the sun, it creates a seal that holds shingles in place against wind forces.
It is one of the most important components for preventing wind uplift.
How Seal Strips Work
After installation:
- Sunlight softens the adhesive strip
- Shingles bond to the course below
- A sealed, interlocked surface is created
This bond:
- Prevents wind from getting under shingles
- Reduces movement and vibration
- Helps maintain the integrity of the roof system
If the seal is broken, the shingle becomes vulnerable.
Why Seal Strips Matter
Wind Resistance
- Primary defense against shingle lift and blow-off
Water Protection
- Helps prevent wind-driven rain from entering beneath shingles
System Performance
- Keeps shingles functioning as a continuous system
Without proper sealing, the roof cannot perform as designed.
Seal Strip Failure
Seal strips can fail due to:
- High winds breaking the adhesive bond
- Age-related deterioration
- Improper installation
- Cold weather preventing proper sealing
When failure occurs:
- Shingles lift easily
- Edges flutter during wind
- Damage spreads across the roof
Once a seal strip is broken, it does not reliably re-seal.
Seal Strips and Wind Damage
Broken seal strips are one of the strongest indicators of wind damage.
Typical signs include:
- Shingles that lift with little resistance
- Creased or bent shingle tabs
- Localized areas of unsealed shingles
Wind damage sequence:
- Wind lifts the shingle edge
- Seal strip bond breaks
- Shingle creases or weakens
This is functional damage — not cosmetic.
Seal Strips in Insurance Claims
Seal strip failure is often the deciding factor in wind damage claims:
Causation Disputes
- Insurance may argue failure is due to age or wear
- Contractors argue storm-related wind damage
Functional Damage Argument
- Broken seal = reduced wind resistance
- Roof no longer meets performance standards
Repair vs Replacement
- Widespread seal failure often supports full replacement
This is one of the most common battlegrounds in roof insurance claims.
How Seal Strips Are Tested
Adjusters and inspectors use a lift test to evaluate seal strip condition:
- Shingles are gently lifted by hand
- Resistance indicates proper sealing
- Easy lift indicates bond failure
Consistent failure across multiple areas supports wind damage.
Common Questions
Can seal strips be repaired?
No — once broken, replacement is typically required.
Is seal strip failure always covered?
No — coverage depends on whether failure is caused by wind or wear and tear.
Can shingles reseal after lifting?
Rarely — especially on older roofs.
Does cold weather affect seal strips?
Yes — low temperatures can prevent proper bonding after installation.
How Claim Advocacy Helps
- Lift testing documentation — proving seal failure
- Damage pattern analysis — linking failure to storm events
- Functional damage explanation — countering cosmetic arguments
- Estimate review — ensuring proper scope
- Supplement preparation — supporting full replacement when justified
Related Glossary Terms
The seal strip is one of the most critical — and most frequently disputed — components of an asphalt shingle roof. When it fails, the roof loses its ability to resist wind and water intrusion. Determining whether that failure was caused by a storm or by age is often the deciding factor in whether an insurance claim is approved or denied.
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📧 gerald@winik.io