Retrofit Guide

ibhs fsm retrofit guide coverDownload the IBHS Wildfire Home Hardening Retrofit Guide for California and Marin.FIRESafe MARIN has been awarded a grant by CSAA Insurance Group to develop a custom home hardening education program and guidebook for California Residents.  Check back late fall 2019 for more information and to register for a Home Hardening education seminar!  The Retrofit Guide available here for download is courtesy of IBHS, the Insurance Institute for Building and Home Safety, and is he top resource available today for homeowners interested in retrofitting existing homes.


Research and post-fire assessments have shown that property owners can protect their homes and businesses against wildfire by addressing three clear sources of vulnerability: materials and design features used in building the home or business, the landscaping vegetation located immediately adjacent to the home or business, and the general vegetation and other combustible materials and items on the property surrounding the home or business. Each of these sources can be dealt with through maintenance, appropriate choices in building materials, design improvements, and vegetation management. 

Making your home or business and community better able to survive a wildfire is a process that will be well worth the effort. Some projects can be done in a weekend, although it is important to remember that routine maintenance must be part of any long-term plan to reduce the vulnerability of your home or business to wildfire. 

This guide was created specifically for Californians and considers appropriate building styles and construction materials, common topographical features, and other factors. While reducing the vulnerability of your home or business to wildfire begins with you, a community-wide approach to fire protection will be the most effective, so please share this guide with friends and neighbors. This guide will provide information that will help your home or business and your community prepare for and survive a wildfire. 

Reducing the Vulnerability of Your Home or Business: An Overview of this Guide 

Wildfires can be difficult to control. What is controllable is how you prepare your home or business for wildfire before it threatens. Ultimately, the difference between survival and destruction are the steps you take to reduce the opportunity for the initial ignition of your home or business. There is an explicit link between the selected vegetation, its placement and management in the area surrounding a building, often referred to as “defensible space,” and construction materials and building design. Survivability of a building will depend on creating and maintaining an effective defensible space on the property and on careful selection of building materials and construction design features. 

The ignition of a building during a wildfire can occur in one of three ways. These include exposure to wind-blown embers (also known as “firebrands”), direct contact by flames, or a radiant heat exposure (radiant heat is the heat felt standing near a burning object, such as a campfire; but during a wildfire, the heat source could include burning items such as a woodpile, tool shed and/or a large shrub). Of these, exposure to wind-blown embers is considered the most important. Wind-blown embers generated by the burning wildland vegetation, or other burning buildings or structures, can land on or near your home or business and ignite it either directly or indirectly. Examples of a direct ember ignition include ember entry through a vent or open window with subsequent ignition of combustible materials or furnishings inside the building. Direct ignition by embers also can occur through sufficient ember accumulation on combustible materials such as a wood shake roof, on combustible decking, or immediately adjacent to combustible materials such as siding. Examples of an indirect exposure include ember accumulation and ignition of vegetation or other combustible materials (e.g., a woodpile or shed) located near your home or business, with subsequent ignition of a building component by a radiant and/or direct flame contact exposure. With inadequate defensible space, the wildfire could burn directly to your home or business and ignite an exterior component, or break the glass in a window and ultimately burn into the interior of the building. Developing and maintaining an effective defensible space will minimize the chance of this happening. 

Once homes and other structures ignite and burn, they will become a source of embers and threaten other homes and buildings. Depending on building-to-building spacing and topographical features, one wildland fire-to-building ignition can result in additional ignitions by building-to-building fire spread. Building-to-building ignitions can result from embers, direct flame contact and/ or radiant heat exposures. The potential damage from radiant heat will depend on the level and duration of the exposure. The radiant heat exposure from a burning building will be longer than that from a burning shrub. 

This guide provides information for reducing the vulnerability of your home or business to wildfire. Vulnerable parts of a building include the roof, the area immediately adjacent to the building and under any attached deck, vents and other openings on the exterior walls, gutters, decks and siding. Specific details on reducing the vulnerability of your home or business will be provided.

Information courtesy of Insurance Institute for Building & Home Safety (IBHS)

Exterior Protection Systems: Sprinklers & Coatings

Wildfire Protection with Sprinklers and Coatings (Foam, Gel, Paint)

Many homeowners ask FIRESafe MARIN for recommendations on exterior foam, gel, and sprinkler systems. Although many seem to believe these are a "common sense" solution, their potential use cases are limited, and there are many considerations that must be balanced before installing such a system. First and foremost: home hardening, through the use of ignition resistant and non-combustible materials, design ,and construction is likely to be more effective, less expensive, and will increase the value and longevity of your home.

  • FIRESafe MARIN does not recommend any exterior sprinkler system which must be manually triggered on-site! You must evacuate early, and it is impossible to predict exactly when a home will be impacted by a wildfire.
  • Exterior garden sprinklers are ineffective and can reduce critical water pressure for entire neighborhoods when many are turned on.
  • Before installing any exterior protection system, consult with your local fire and building officials, and ensure that you have created an immaculate Defensible Space, and retrofitted all aspects of your building with the wildfire home hardening techniques outlined on this website.
  • Beware of snake oil! Be alert for manufacturers overselling their product's capabilities, and know that there are no magic solutions to protect an otherwise vulnerable home from wildfires.
  • Retrofitting exterior materials and designs with home hardening techniques is likely to be more effective than any exterior sprinkler, foam, or gel system.
  • FIRESafe MARIN does not recommend any particular product(s).


Functionality and Installation

fema sprinkler coverDownload the FEMA Guide, Wildfire Sprinklers: Home Builder’s Guide to Construction in Wildfire Zones

The function of an exterior sprinkler system is to minimize the opportunity for ignition by wetting the home and surrounding property. Sprinkler systems should be able to protect a home against the three basic wildfire exposures: wind-blown embers, radiant heat and direct flame contact.

Sprinklers systems can be mounted in one or more locations, including:

  • The roof (Photo 1).
  • Under the eave at the edge of the roof.
  • On the property, in which case the sprinklers are directed at the home from multiple locations surrounding it. Ember ignition of combustibles located on or near the home can result in a radiant and/or flame contact exposure (Photo 2). Water should reach all vulnerable areas for the system to have maximum effect both on and near the home (Photo 3).

Potential Issues

Post-fire assessments have shown exterior sprinkler systems can be effective in helping a home survive a wildfire, but potential issues exist with their use. These issues include:

  • The water supply should be adequate to deliver water, when needed, for the time embers could threaten a home. This period could be up to 8 hours.
  • Check with your local fire department if your sprinkler system uses water from a municipal supply; they may have suggestions to help minimize water consumption.
  • The effectiveness of a sprinkler system is questionable when a neighboring home is burning, since this would result in an extended radiant heat and/or contact exposure to the home.
  • These systems can be activated manually or by an automated device, such as a sensor that detects heat or flame, or by an SMS-enabled cell phone. The ability of these systems to activate based strictly on an ember exposure has not been determined. Since wind-blown embers can be transported for up to a mile from the flame front of a wildfire, this may be a limitation.
  • The most threatening wildfires occur during high-wind events and the homeowner should consider how the distribution/transport of water droplets may be influenced by elevated wind speeds.


Given the potential issues regarding performance, it’s recommended that use be a supplement to, and not a replacement for, already proven mitigation strategies, such as the reduction of potential fuels throughout the home ignition zones, along with removal of roof and gutter debris, and use of noncombustible and fire/emberignition resistant building materials and installation design details


Interior sprinkler systems, designed to protect homes from interior fires, are extremely effective and save lives.  They are required on most new constrcution in marin.  They provide no protection against wildfires.


Foams, Gels, Intumescent Paint

Buildings threatened by wildfire can be mitigated through the development of a strategy that addresses the built environment, vegetation, and other combustible materials on the property. Use of noncombustible materials and ember-resistant design features are examples of strategies that reduce the vulnerability of homes to wildfire. The use of coatings has been suggested as a strategy to provide enhanced protection against extended radiant heat and flame contact exposures for homes located in wildfire-prone areas, particularly when a combustible siding product is installed and other homes are nearby. In these cases, it can be argued that applying a coating is a less expensive option than replacing a combustible product with one that is noncombustible.


The term “coatings” is a generic term referring to products that are applied to various building components. These building components can be combustible or noncombustible materials and are used to provide added protection from various environmental factors. The most common use for coatings applied on wood, and wood-based products, is to provide protection from water or water vapor where the coating reduces the rate that moisture enters and leaves. Depending on additives and the chemical makeup, coatings can also improve the fire retardancy or fi re resistance of the wood or other combustible material.


Another example of a coating is what’s commonly referred to as a “gel.” Gels are water absorbent polymers that can be applied to a building component to provide temporary protection from radiant heat or fl ames. You may have heard of these products being applied to homes when a wildfi re is threatening. Once applied, the absorbed water starts to evaporate, whether or not the wildfi re actually arrives, and therefore the time that a gel coating is effective is limited. The effective time is on the order of hours.


A common example of a coating providing enhanced performance when exposed to fire is intumescent paints (i.e., they form a film when dry). When an intumescent coating is heated by elevated levels of radiant heat, or flames, it can swell up to 20 times the original dry-film thickness; creating an insulation layer that may provide some level of the combustible building component.

Intumescent coatings are commonly used in interior applications. However, caution is advised when these products are used in an exterior application. Researchers at the USDA Forest Service Forest Products Laboratory reported that fire-retardant coatings have an uncertain “shelf life” when used in an exterior location and would therefore need to be reapplied regularly. 

If an intumescent coating is being considered, ensure the manufacturer has provided test results demonstrating enhanced performance, either after a defined accelerated weathering period or an extended natural weathering period. Acknowledging their uncertain performance when used in exterior applications, the use of coatings is not allowed for compliance with provisions of the California Building Code, Chapter 7A, which provides requirements for building in wildfire-prone areas in California.


Given the current performance limitations of coatings, we recommend other proven mitigation strategies to reduce the vulnerabilities of homes to wildfi re, such as using ember-resistant design features and creating and maintaining Defensible Space zones.

Keep in mind

  1. If you have a fire resistant roof, and keep it (and rain gutters) clean at all times during fire season as you are REQUIRED to do, sprinklers will not make a difference for your house!
  2. Home hardening materials and methods are likely to be more effective, and less expensive, than a sprinkler, foam, or gel system.
  3. Wide-scale activation of sprinklers and garden hoses may reduce water pressure in the entire community.  Firefighters apply water judiciously, where it actually makes a difference, and will need all available water and water pressure.
  4. If the fire is close enough to make turning-on a manually operated sprinkler system a viable option, you should have already evacuated.  In-turn, turning on the water in advance can potentially drain local water supply tanks and reduces water pressure available for firefighting (see above).  Fire is dynamic and difficult to predict - in most situations, you will not have enough information to know when the fire might reach your house.
  5. Climbing your roof when a fire approaches is dangerous.  If you fall or are are injured, firefighters will need to rescue you instead of fighting the fire.
  6. Local fire agencies agree that a sprinkler system on the roof MAY be advisable is if you have a combustible wood roof.  Even then, FIRESafe MARIN recommends that you replace any wood-shake roof with a fire-esistant "Type A" roof assembly, rather than installing a sprinkler system.  Contact your local Fire Marshal for advice.
  7. Likewise, don't climb up on your roof with a garden hose.  You've seen it on the news - Californians dutifully stand on their roof with a garden hose and watch the firefighters work nearby.  This is dangerous (you should have already evacuated, and your shorts and tennies won't protect you if the fire reaches you), not to mention completely ineffective.

As your neighborhood becomes more active in wildfire prevention, you'll likely find many products and engineering ideas that will be sold to you under the guise of reducing your risk.  Some may be effective, many are not.  Products like "fireproof" paint, heat activated shutters, automatic (exterior) sprinkler systems, foam and gel coatings, even whole house fire retardant blankets are all available.  While some may be effective in certain scenarios, many are a waste of money.  Even worse, some are snake oil.  Contact your local Fire Department or FIRESafe MARIN before purchasing anything intended to "fireproof" your home (this does not apply to the WUI building products required by Chapter 7A of the Building Code).

There are three strategies that are PROVEN to protect your home from wildfires:

  1. Hardening Your Home: steps taken in advance to "harden" your home against wildfire include maintaining a fire resistant "Class A" roof (required for all new construction and remodels);  covering ALL vents with 1/8" or smaller wire mesh; caulking all openings and cracks in siding, eaves, rafters, etc; removing combustibles above and below decks; sealing doors and windows with weather stripping to keep out embers; updating windows to multi-paned tempered glass; and many more online at hardening
  2. Defensible Space:  It's required by law and extremely effective at reducing your home's exposure to radiant heat and protecting from embers.  A clean roof is part of maintaining Defensible Space, same as maintaining and removing combustible vegetation for 100' (or to your property line).
  3. Community Scale Vegetation Management: this requires working together as a community, cooperating with neighbors, and altering your mindset to understand that we need to maintain local forest and vegetation communities in a healthy state.  This can only happen when everyone works together - it's everyone's responsibility.

Marin Fire Departments

Marin residents are served by a variety of local municipal fire departments and fire districts. Each fire agncy in Marin partners and works closely with FIRESafe MARIN to assist Firewise USA neighborhoods and provide wildfire safety education, planning, and hazard mitigation.

Your local fire department is responsible for enforcement of the Fire Code, setting standards, and providing community safety education and services. All fire departments share responsibility for emergency response, and work together closely through a “mutual aid” system to ensure a statewide response to major wildfires and other large emergency incidents. Get to know your fire department!

bolBolinas Fire Protection District

Service Area:

100 Mesa Rd, PO Box 126
Bolinas, CA 94924

(415) 868-1566

cmdCentral Marin Fire Department

Service Area:
Corte Madera, Larkspur, incorporated Greenbrae

342 Tamalpais Dr
Corte Madera, CA 94925

(415) 927-5077
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invInverness Public Utilities District

Service Area:
Inverness Public Utilities District

50 Inverness Way
Inverness, CA 94937

(415) 669-7151
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kntKentfield Fire Protection District

Service Area:
Kentfield, unincorporated Greenbrae

1004 Sir Francis Drake Blvd
Kentfield, CA 94904

(415) 453-7464
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mrnMarin County Fire Department

Service Area:
Marin City, Throckmorton Ridge, West Marin (Forest Knolls, Hicks Valley, Lagunitas, Nicasio, Point Reyes, San Geronimo, Tomales, Woodacre)

33 Castle Rock Rd, PO Box 518
Woodacre, CA 94973

(415) 473-6717
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mrwMarinwood Fire Department

Service Area:
Marinwood Community Services District

777 Miller Creek Rd
San Rafael, CA 94903

(415) 479-0122

novNovato Fire Protection District

Service Area:
Incorporated and unincorporated Novato

95 Rowland Way
Novato, CA 94945

(415) 878-2690
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rvyRoss Valley Fire Department

Service Area:
Ross, San Anselmo, Fairfax, Sleepy Hollow

777 San Anselmo Ave
San Anselmo, CA 94960

(415) 258-4686
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mlvMill Valley Fire Department

Service Area:
City of Mill Valley

1 Hamilton Dr
Mill Valley, CA 94941

(415) 389-4130
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snrSan Rafael Fire Department

Service Area:
San Rafael

1600 Los Gamos Dr Suite 345
San Rafael, CA 94901

(415) 485-3304

somSouthern Marin Fire District

Service Area:
Sausalito, Tam Valley, Homestead Valley, Strawberry, parts of unincorporated Tiburon and Mill Valley

308 Reed Blvd
Mill Valley, CA 94941

(415) 388-8182
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stnStinson Beach Fire Department

Service Area:
Stinson Beach

PO Box 308
Stinson Beach, CA 94970

{415) 868-0622

tibTiburon Fire Protection District

Service Area:

1679 Tiburon Blvd
Tiburon, CA 94920

(415) 435-7200



FIRESafe MARIN strongly discourages the use of foam insert gutter guard materials, even if the manufacturer makes claims related to fire-resistance.  In our informal testing, these materials were highly combustible, ignite easily, and spread fire rapidly.  We've contacted the California State Fire Marshal and Consumer Product Safety Commission to ask for assistance in removing these products which are being aggressively marketed to homeowners in the WUI.

In this video, a small amount of leafy debris was applied to DAMP foam gutter guard, sold at Home Depot with "Fire Resistant" in the product's name! Although the leafy material barely sustained flame, the foam material ignited readily and sustained combustion, exhibiting 12-16" flames and emitting acrid black smoke.

Gutters play a role in providing a means of collecting and directing rainwater from the roof into downspouts, and then away from the house. This helps reduce the amount of water in the soil that can enter the crawlspace or basement and result in moisture-related performance problems such as those from mold and wood decay fungi.

Combustible debris such as leaves and pine needles can accumulate in gutters, especially from nearby or overhanging trees. Due to difficulty in accessing upper stories of a home, gutters two and three floors high are even more problematic, since they will be difficult to clean out on a regular basis. If ignited, combustible debris in the gutter will expose the edge of the roof covering, typically the fascia and or roof sheathing. Depending on the condition of the wood and presence (or absence) of metal flashing at the edge of the roof, debris in the gutter may make it easier for fire to enter the attic. Metal flashing at the roof edge will provide additional protection to the roof edge and therefore is a recommended detail.

gutter-debris vegetation

As shown in the photograph below, the roof deck boards in this eave overhang area are decayed. These boards would be more easily ignited if debris in the gutter ignited, In this case, angle flashing at the roof edge was used, but the poor condition of the roof would still make this a vulnerable area.

Decayed boards - under eave

Metal gutters have been recommended over plastic gutters in fire hazard areas. Embers will ignite accumulated debris in any gutter. Metal gutters will stay in place, and therefore the resulting fire will continue to burn at the roof edge. Vinyl (or plastic) gutters will quickly detach and fall to the ground. The debris and combustible gutter material will continue to burn, igniting any combustibles (mulch, vegetation, wood piles) and potentially any combustible siding. Flames can be high enough to impinge on windows. If you have vinyl gutters, a noncombustible (or low flammability) zone near the home is critical (e.g., use noncombustible rock mulch and carefully selected and maintained vegetation). If you have metal gutters, make sure the components at the roof edge are well maintained. Regardless of the gutter material, clean out debris in the gutter on a regular basis.

Gutter guards or covers can be installed over or in your gutters. When properly installed (and maintained), these can reduce the amount of vegetation litter and debris that accumulate in your gutter and therefore reduce the need to clean it. Some products can become dislodged over time, and they will have to be reinstalled when this happens. Some products can result in the accumulation of debris on the roof, behind the gutter. There are a number of commercially available products specifically intended for this purpose - just type gutter guard in a web-browser search engine to get an idea of the available products. To date, there isn’t a standard procedure to evaluate the performance of these products. 

roof gutter guard

Note that some of the covers in the gutters on this roof have dislodged, and therefore no longer keep out debris. Gutter guards should be inspected regularly, and reattached when necessary.

The following photograph shows debris that has accumulated behind the gutter cover. This Class A roof covering will be able to handle the fire if this debris is ignited by embers, but because of the proximity to the roof edge, this debris should be removed from the roof.

Debris accumulation behind gutter cover

It is possible that your home won't have gutters. Although this will eliminate any 'debris accumulation' issue, it will result in a heavy rain load around your home, and depending on drainage, may contribute to moisture related problems.

[From the Uiversity of California Homeowner's Wildfire Mitigation Guide]

Roof and Gutter Cleaning Tips

  1. Be safe!
    1. Hire a professional if you are unsure or lack the proper tools.  Some roofing materials can be damaged if you walk on them, and every roof poses a fall hazard.  
    2. Always use a sturdy, well-footed ladder to reach your roof and gutters.
    3. Don't clean your roof alone.  Be sure there is someone with you, on the ground, to help when needed.
  2. Check your roof.  Is it well maintained?  Is the roofing made from a fire resistant (Class "A") material like tile, composite shingles, or tar and gravel?  It can be difficult to tell whether you have a Class “A” fire-rated roof, unless it’s made of an obviously noncombustible material, such as tile.  If you are not sure about your roof, schedule a professional roof inspection to find out.
  3. Always keep your roof clean of debris.  Clean it as often as necessary during fire season.  Remember: even a tiny handful of leaves is enough to burn your home!
  4. Check your gutters.  Metal gutters are safest, and all gutters must be maintained completely free of leaves, needles, and vegetation during fire season (and the rainy season too, or course).  Like the rest of your roof, you may need to clean them more often during the summer if you live in an area where leaves are likely to fall onto your roof.

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