Ventilation Retrofits- . NCO Inc. . 2025

Protecting Your Exterior Vents and Access from Wildfire:

While vents may seem small, they can become major entry points for wildfire hazards. Embers can easily sneak through poorly protected vents, landing in attics, crawlspaces, and walls, where they can ignite flammable materials out of sight. Upgrades like ember-resistant vent covers or fine metal mesh are your home's first defense in blocking these dangerous intruders. Whether you’re replacing old vents or reinforcing them with mesh, maintaining these vulnerable spots is crucial. Make sure your vents aren’t just providing airflow, but are also keeping embers out and your home safe during a wildfire.

Key Points:

Block Ember Intrusion: Install ember-resistant vent covers or fine metal mesh to prevent embers from entering attics or crawlspaces.
Replace Old Vents: Swap damaged or noncompliant vents for California-approved flame and ember-resistant models.
Metal Mesh Option: Cover ridge and gable vents with fine metal mesh if full replacement isn’t possible.
Seal Gaps: Use fire caulking and fire stop systems to close gaps and keep embers out.
Balance Airflow and Safety: Ensure vents provide proper airflow while using ember-resistant upgrades to protect your home during wildfires.

This section outlines methods to strengthen birdhole, under-eave, ridge, off-ridge, gable, and crawlspace vents to meet California's Wildfire Mitigation Program Code. Here's a breakdown:

Vent Retrofits:

Enclosure of Under Eaves for Maximum Protection:

Install noncombustible soffit material, such as fiber-cement boards, to enclose and protect under-eave vents from ember intrusion.
Ensure that fascia boards are included in the installation for complete fire resistance around your roof's edges.
Follow the manufacturer’s instructions and relevant building codes (CBC or CRC) to maintain proper ventilation and code compliance.

Flame and Ember-Resistant Vent Replacement:

Replace noncompliant or damaged vents (except ridge and off-ridge vents) with California OSFM-approved flame and ember-resistant vents.
Ensure proper ventilation after installation (following CBC or CRC guidelines).
Follow the manufacturer's instructions and building code requirements (CBC or CRC) for vent installation.
Seal any gaps around the vent to prevent ember intrusion.
Dispose of old vents at an approved disposal site.
Provide documentation showing compliance with ventilation codes after installation.

Metal Mesh Vent Retrofit (for Specific Vents):

If replacing certain vents (e.g., ridge, off-ridge) with flame-resistant vents isn't feasible, cover them with fine metal mesh (1/16" to 1/8" diameter).
This option addresses ember vulnerability only, not flame intrusion.
Ensure proper ventilation after installation (following CBC or CRC guidelines).
Follow the manufacturer's instructions and building code requirements (CBC or CRC) for vent installation.
Seal any gaps around the vent to prevent ember intrusion.
Properly dispose of old vents at an approved site.
Provide documentation showing compliance with ventilation codes after installation.

Fire Caulking & Fire Stop Systems:

Use fire caulking that meets ASTM E814 (UL 1479) fire code testing standards.
Ensure there are no gaps around vents or areas where embers could enter, using fire caulking to seal gaps smaller than 1/4 inch.
Protect penetrations with an approved firestop system, installed according to ASTM E119, ASTM E814, UL 263, or UL 1479 standards.
Provide documentation showing compliance with fire code regulations after installation.

Compliance References:

CBC (California Building Code): Sections 1202, 706A.2, 706A.2.1
CRC (California Residential Code): Sections R806, R337.6.2, R337.6.2.1

Disclaimer: The California Wildfire Mitigation Program Home Hardening Initiative recommends the following measures to retrofit a residence. Please note that not all retrofits listed are available in the Lake County Home Hardening Program.