ICC-ES Certified Flood Vents

The distinction determines NFIP compliance and insurance eligibility.

Non-Engineered (Prescriptive) Flood Vents:

• Simple openings meeting minimum size (1 sq in per sq ft of enclosed area)
• No certification required
• Must be completely open (no screens, louvers, or coverings)
• Limited to basic foundation wall installations
• No performance testing or validation

Engineered Flood Vents:

• Designed and tested to meet specific performance standards
• ICC-ES certification validates compliance with federal regulations
• May include screens, louvers, or coverings while maintaining automatic operation
• Accepted by local officials and insurance providers nationwide
• Covers more area per vent (our vents: 220 sq ft each vs. 150 sq ft typical for prescriptive)

Why Engineered Matters:

• Insurance providers require documentation for premium reductions
• ICC-ES certification provides that documentation
• Building officials accept certified products without additional engineering
• Greater flexibility in application and installation

Bottom Line: Engineered vents with ICC-ES certification provide verified performance and official documentation required for flood insurance benefits.

Calculate based on enclosed area square footage below base flood elevation.

Calculation:

1. Measure total square footage of enclosed area
2. Divide by the coverage per vent
3. Round UP to nearest whole number
4. Minimum of 2 vents required on opposing walls

Examples:

• 880 sq ft crawl space: 880 ÷ 220 = 4 vents minimum
• 1,320 sq ft garage: 1,320 ÷ 220 = 6 vents minimum
• 550 sq ft enclosed area: 550 ÷ 220 = 2.5, round to 3 vents

Distribution Requirements:

• Place vents on at least two opposing foundation walls
• Distribute evenly around perimeter for balanced pressure equalization
• Position no more than 12 inches above adjacent grade
• Space at least 3 feet apart for effective water flow

Why Opposing Walls Matter: Floodwater must flow both IN and OUT freely. Vents on one wall only create bottleneck that prevents proper pressure equalization.

Choose based on your crawl space ventilation strategy.

Multi-Purpose Flood Vents (with Air Circulation):

• 37 sq in continuous ventilation through louvers during normal conditions
• Automatic flood protection when needed
• Best for: Traditional vented crawl spaces with open foundation vents
• Provides both moisture control and flood compliance
• Maintains airflow year-round

Sealed Flood Vents (No Air Circulation):

• Solid construction with no ventilation during normal conditions
• Automatic flood protection when needed
• Best for: Encapsulated crawl spaces with vapor barriers and dehumidifiers
• Maintains sealed environment while meeting flood requirements
• Prevents humid outdoor air infiltration

Key Decision Factor: If you have a vapor barrier and dehumidifier (encapsulated), use sealed vents. If you rely on traditional ventilation through foundation vents, use multi-purpose vents.

Both Types: ICC-ES certified, 220 sq ft coverage, automatic operation, available in black/white/gray.

Yes, but premium reduction varies based on multiple factors.

How Flood Vents Reduce Premiums:

• Allow automatic floodwater entry and exit
• Equalize hydrostatic pressure on foundation walls
• Prevent structural damage from trapped water pressure
• Reduced damage risk = lower insurance premiums

Factors Affecting Your Reduction:

• Base flood elevation vs. your structure elevation
• Number of feet below base flood elevation
• Flood zone designation (A, AE, VE, X, etc.)
• Current policy coverage levels
• Geographic location and flood history

To Get Premium Reduction:

1. Install ICC-ES certified flood vents meeting NFIP requirements
2. Ensure installation meets local building codes
3. Obtain documentation (ICC-ES certificate, installation photos)
4. Contact flood insurance provider to request premium re-evaluation
5. Submit certification documentation

Typical Savings: Vary widely from hundreds to thousands annually depending on risk reduction achieved. Contact your insurance provider for estimate based on your specific property.

Important: ICC-ES certification is essential—insurance providers require certified products for premium reductions.