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Home Hardening

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Home Hardening: Building a Fire-Resistant Structure

Building on the foundation of Wildfire Awareness, Preparedness & Defensible Space, which manages the vegetation surrounding your property, Home Hardening focuses on the physical structure itself.  In Amador County, where wildfire risk is greater that 98% of all U.S. counties, hardening your home is a critical step in reducing vulnerability to fire and smoke.

Home Hardening involves using ignition-resistant materials and design techniques to protect your home from three primary threats: Direct Flame Contact, Radiant Heat, and Flying Embers.  Embers pose a significant threat, as they can travel ahead of the fire front and enter through vents and gaps, igniting the structure from within.

Priority Areas for Home Hardening

To effectively harden your home, focus on the most vulnerable components where embers or heat are likely to cause ignition.

Roof & Chimneys:

The roof is the most vulnerable part of your home due to its large surface area.

  • Roofing Material: Opt for composite, asphalt, metal, clay, or tile roofing to resist fires.  Homes with wood shingle roofs are at high risk.
  • Ember Sealing: Close off gaps under roof tiles and shingles to block wind-blown embers.
  • Debris Removal: Regularly clear leaves, pine needles, and other debris from the roof.
  • Chimney Screening: Cover chimney and stove pipe outlets with non-flammable metal screen with openings between 3/8" - 1/2".
  • Seasonal Precautions: Close the fireplace flue during wildfire season when not in use.

Vents & Windows:

Vents are essential for airflow but can act as entry points for embers.

  • Mesh Screening: Install 1/16" - 1/8" noncombustible, corrosion-resistant metal mesh over all vents.  Avoid fiberglass or plastic meshes, which can melt.
  • Advanced Vents: Consider replacing standard vents with California State Fire Marshal-approved flame and ember-resistant vents.
  • Dual-Pane Windows: Install dual-paned windows with at least one layer of tempered glass to withstand breakage from heat.
  • Window Screens: Add screens to all operable windows to catch embers and reduce radiant heat.

Walls, Decks, & Fences:

The materials on your home's exterior and its attachments can bridge fire to the main structure.

  • Siding Materials: Use ignition-resistant materials such as stucco, fiber cement, or specially treated wood.  Ensure materials extend from the foundation to the roofline.
  • Decks: Construct decks from ignition-resistant or noncombustible materials.
  • Under-Deck Area: Maintain an ember-resistant zone beneath decks by removing all flammable materials.
  • Fencing: Use noncombustible materials (like metal or masonry) for the portion of the fence that connects directly to the house to prevent fire spread.

Eaves, Gutters, & Garages:

  • Eaves & Soffits: Box in eaves using ignition-resistant or noncombustible materials to prevent ember entry.
  • Rain Gutters: Keep gutters free of plant debris and install noncombustible gutter covers.
  • Drip Edge: Add a noncombustible metal drip edge to protect the roof's edge from ember exposure.
  • Garage Seals: Apply weather stripping around and under the garage door to block embers.  Equip garage doors with battery backups for functionality during power outages.

Low-Cost Retrofitting & Maintenance

Hardening your home does not always require a major remodel.  Several impactful steps can be taken with minimal investment.

  • When it's time to replace your roof, replace it with a Class A fire-rated roof.  Visit https://osfm.fire.ca.gov/what-we-do/fire-engineering-and-investigations/building-materials-listing for more information.
  • Install a noncombustible gutter cover on gutters to prevent the accumulation of leaves and debris in the gutter.
  • Block any spaces between your roof covering and sheathing with noncombustible materials.
  • Cover your chimney and stove pipe outlets with a noncombustible, corrosion-resistant metal mesh screen (spark arrestor) with 3/8" - 1/2" openings.
  • Install ember and flame-resistant vents.  Consult your local building official and hire a licensed contractor for this project as these modifications may reduce airflow.
  • Caulk and plug gaps greater than 1/8" around exposed rafters and blocking to prevent ember intrusion into the attic or other enclosed spaces.
  • When it's time to replace your windows, replace them with multi-paned windows that have at least one pane of tempered glass.
  • Install weather-stripping to gaps greater than 1/8" between garage doors and door frames to prevent ember intrusion.  The weather-stripping must be compliant with UL Standard 10C.
  • Inspect exterior siding for dry rot, gaps, cracks, and warping.  Caulk or plug gaps greater than 1/8" inch and replace any damaged boards, including those with dry rot.
  • When it's time to replace your siding or deck, use compliant noncombustible, ignition-resistant or other OSFM Wildland Urban Interface (WUI) Products.  Click here for more information. 
  • Install a minimum 6" metal flashing, applied vertically on the exterior of the wall at the deck-to-wall intersection to protect the combustible siding material.
  • Cover openings to operable skylights with a noncombustible metal mesh screen with opening in the screen not to exceed 1/8"
  • Replace wood mulch products within five feet of all structures with noncombustible products such as dirt, stone, or gravel.
  • Regularly clean your roof, gutters, decks, and the base of walls to avoid the accumulation of fallen leaves, needles, and other flammable materials.
  • Ensure that all combustible materials are removed from underneath, on top of, or within five feet of a deck. 
  • Ensure exposed firewood is stored at least 30 feet away from structures or completely covered in a fire-resistant material that will not allow embers to penetrate.  Additionally, make sure you have 10 feet of clearance around your wood piles.
  • Remove vegetation or other combustible materials that are within five feet of windows and glass doors.
  • Be sure to store combustible outdoor furnishings away from your home when not in use.
  • Remove all dead or dying grass, plants, shrubs, trees, branches, leaves, weeds, and pine needles within 30 feet of all structures or to the property line. 
  • Remember to properly store retractable awnings and umbrellas when not in use so they do not collect leaves and embers. 

Staying Informed

Timely information is vital during a wildfire.  Only rely on trusted sources of instructions.

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