Ice and Water Shield Application

Why this matters

Ice and water shield is the self-adhering membrane installed at vulnerable roof areas to protect against ice dam infiltration. Required in cold climates by IRC R905; recommended in mild climates for additional protection. A roofing contractor's understanding + proper installation is essential for cold-climate work.

Where it's required

Per IRC R905:

Specific requirements vary by jurisdiction.

Why ice + water shield

The protection against:

• Ice dam formation at eaves
• Water backup behind dams
• Wind-driven rain at vulnerable areas
• Penetration leaks
• Roof valley water concentration

Each is a documented leak source.

How it works

The membrane:

• Self-adhering
• Bonds to the deck below
• Bonds to nails through it (creates self-sealing)
• Provides waterproof seal beneath shingles
• Resistant to back-pressure

When ice dams form:

1. Snow melts on warm part of roof
2. Refreezes at the cold eave
3. Forms dam blocking drainage
4. Water backs up under shingles
5. Ice and water shield prevents leak

Materials

For ice + water shield:

Most installations use modified bitumen rubberized.

Width at eaves

Per IRC R905:

• Minimum 2 feet (24 inches) past the warm wall line
• Where the warm wall is the interior wall closest to the eave
• Measured from the exterior eave inward

For typical residential: 36-48 inches of ice shield at the eave.

Installation procedure

Step 1: Roof deck preparation

1. Clean
2. Smooth (no debris)
3. Dry

Step 2: Underlayment preparation

For ice shield specifically:

1. No additional underlayment under (for the shield)
2. Shield applied directly to deck
3. Shield bonds to deck

Step 3: Apply ice shield

1. Start at the eave
2. Apply directly to the deck
3. Width per requirements
4. Adhere fully (no air pockets)
5. Overlap pieces properly (per manufacturer)

Step 4: Continue with standard underlayment

1. Standard underlayment above the ice shield
2. Overlapping the ice shield by 6 inches minimum
3. Standard installation

Step 5: Install shingles

1. Standard shingle installation
2. Penetrating nails seal in the ice shield
3. Standard roofing approach

Common installation details

For specific areas:

Valleys

1. Center the ice shield in the valley
2. Extend 18 inches each side of the centerline
3. Full coverage of the valley path

Skylights / penetrations

1. Apply ice shield around the penetration
2. Wrap up the sides of the curb
3. Standard flashing over

Chimneys

1. Apply ice shield around the chimney
2. Wrap up the sides
3. Standard counterflashing over

Roof-to-wall transitions

1. Apply ice shield at the transition
2. Wrap up the wall
3. Standard flashing over

When ice + water shield isn't required

For milder climates:

• IRC doesn't require in warm areas
• Some jurisdictions have stricter rules

Recommended for additional protection regardless.

Customer education

For customers:

1. "Ice + water shield protects against ice dam damage"
2. "Required in cold climates by code"
3. "Premium protection beyond standard"
4. "Customer's home is protected in worst-case"

A trained customer values the protection.

Cost vs. value

The cost:

• Per linear foot of eave coverage
• Higher than standard underlayment
• Customer's marginal investment
• Significant protection

A worthwhile addition to most roofing.

Manufacturer warranties

For ice + water shield:

• Material warranty (manufacturer)
• Installation warranty (roofer)
• Specific exclusions

Document for the customer.

When the customer wants additional

For customers wanting:

• Full roof ice + water shield (over the entire roof)
• Significant cost premium
• Maximum protection
• Customer's specific choice

Some customers in severe climates choose this.

Coordination with insulation

Ice dam prevention:

• Adequate insulation
• Adequate ventilation
• Ice + water shield (last line of defense)

Each addresses the problem.

When the customer's home has chronic ice dams

If recurring:

1. Identify the cause (often inadequate insulation / ventilation)
2. Address the cause (cheaper long-term)
3. Plus ice + water shield (protection)
4. Customer's comprehensive solution

Don't rely on ice + water shield alone.

Specialty: heated cables

For some homes:

• Heated cables at the eave (separate from ice + water shield)
• Energy-intensive
• Customer's choice

Less common but available.

Documentation

For each installation:

1. Width applied
2. Specific areas covered
3. Manufacturer + product
4. Customer file note

When the customer has water damage

For ice dam damage:

• Verify ice + water shield was applied
• If missing: customer's roofer's issue
• Insurance + warranty
• Customer's options

The customer's protection depends on the install.

Cold-climate considerations

For severe winters:

• Code requirements stricter
• Customer's specific needs
• Wider coverage sometimes recommended
• Customer's investment

Cold-climate customers benefit significantly.

Hot-climate considerations

For warm climates:

• Code may not require
• Less critical for ice dam
• May still help for wind-driven rain

Some customers in mild climates choose for storm protection.

Common pitfalls

• Skipping the ice + water shield in cold climate - code violation + customer damage
• Wrong width - inadequate protection
• Improper installation - leaks despite the shield
• No coordination with insulation / ventilation - ice dams continue

Installation in cold weather

For winter installation:

• Some adhesives don't work well in cold
• Verify manufacturer recommendations
• Customer's timing consideration

Best installed in warm weather.

When the roof needs replacement

For old roofs:

• Ice + water shield may be replaced
• Customer's investment in protection
• Modern materials better

A reroof should include modern ice + water shield.

Customer's homeowner's insurance

For ice dam damage:

• Some policies cover
• Others don't
• Customer's specific policy
• Documentation supports

The customer's investment in ice + water shield reduces claims.

Specialty: synthetic underlayment

For modern installations:

References

• IRC R905 (Roofing)
• IBC Chapter 15 (Roofing)
• IECC (energy code; ice dam prevention through insulation)
• Manufacturer documentation (Grace, GAF, Carlisle, etc.)
• NRCA (National Roofing Contractors Association) installation standards
• Manuall internal: Asphalt Shingle Replacement SOP, Ice Dam Prevention, Roof Slope and Measurements