Federal Insurance and Mitigation Administration

Returning to your fire-damaged home will undoubtedly 

be an emotional experience. But as you go about the 

task of rebuilding, there are many ways to rebuild safer, 

stronger, smarter, and more resilient to wildfires. The 

Federal Emergency Management Agency (FEMA) has 

teamed with Firewise Communities, the Federal Alliance for Safe Housing, and the Institute for Business 

and Home Safety to provide this resource for rebuilding 

after a fire.

Just the Right Conditions

Conditions must be just right for a wildfire to start and 

spread. Specifically, fuel, weather, and topography 

work together to determine how quickly a wildfire travels and at what intensity.

 Fuels: The two basic fuel types in the wildland/urban 

interface are vegetation and structures.

 Vegetation: Fuel in its natural form consists of living and dead trees, bushes, and grasses. Typically, 

grasses burn more quickly and with less intensity 

than trees. Any branches or shrubs between 18 inches and 6 feet are considered to be ladder fuels. Ladder fuels help convert a ground fire to a crown fire 

(tree tops), which moves much more quickly. Check 

with your local cooperative extension service to get a 

list of local plants that are less flammable.

 Structural Density: The closer the homes are together, the easier it is for the flames to spread from 

one structure to another.

 Weather: High temperatures, low humidity, and 

swift winds increase the probability of ignitions and 

difficulty of control. Short- and long-term droughts 

further exacerbate the problem.

 Slope: Slope is the upward or downward incline or 

slant of terrain. For example, a completely flat plain 

represents a 0 percent slope and a hillside that rises 

30 feet for every 100 feet horizontal distance 

represents a 30 percent slope. Hot gases rise in front 

of the fire along the slope face, pre-heating the upslope vegetation, moving a grass fire up to four times 

faster with flames twice as high as a fire on level 

ground.

How a Home Catches Fire

There are three ways that the wildfire can transfer itself 

from the natural vegetation or other burning homes –

through radiation, convection, or firebrands.

 Radiation: Wildfires can spread by radiating heat in 

the same way a radiator heats rooms in the wintertime. Radiated heat is capable of igniting combustible materials from distances of 100 feet or more.

 Convection: Contact with the convection column 

(flames) may also cause the wildfire to ignite homes 

and other buildings. Typically, the convective heat 

column rises vertically, within the smoke plume.

 Firebrands: Firebrands are burning materials that 

are blown by fire-generated winds. Firebrands can be 

carried long distances – more than a mile.

In all cases, your home’s building materials and design 

play a significant role in establishing the level of exposure that can be endured before ignition from radiation, 

convection, firebrands, or any combination of these 

three.

Rebuilding After a Wildfire
Federal Insurance and Mitigation Administration

Rebuilding After a Wildfire

Creating a Survivable Space for 

Your Home 

A survivable space is an area of reduced fuels between 

your home and the untouched wildland. This provides 

enough distance between the home and a wildfire to 

ensure that the home can survive without extensive effort from either you or the fire department. The space 

also allows the fire department more time to fight the 

fire before it reaches your home. One of the easiest ways 

to establish a survivable space is to use the zone concept. Zone 1 is the closest to your home and Zones 2 and 

3 move progressively farther away.

 Zone 1: Establish a well-irrigated area around your 

home. It should extend a minimum of 30 feet from 

your home on all sides. But as much as 50 to 100 feet 

may be necessary, depending on your risk, especially 

on any downhill sides of the lot.

 Zone 2: Place low-growing plants, shrubs, and carefully spaced trees in this area. Maintain a reduced 

amount of vegetation. Your irrigation system should 

also extend into this area. Trees should be at least 10 

feet apart, and all dead or dying limbs should be 

trimmed. For trees taller than 18 feet, prune lower 

branches within 6 feet of the ground. No tree limbs 

should come within 10 feet of your home.

 Zone 3: This farthest zone from your home is a 

slightly modified natural area. Thin selected trees and 

remove highly flammable vegetation such as dead or 

dying trees and shrubs.

The Importance of Maintenance

Once you have created your home’s survivable space, 

you must maintain it or risk losing the benefit of its protection. Treating and maintaining a survivable space is a 

necessary first step. The next step is to use fire-resistant 

building materials and construction techniques in retrofitting your home.

The Ideal Fire Resistant Home

Keep in mind that a wildfire sees your home as just another fuel source. The survivable space you construct 

around your home will keep all but the most ferocious 

wildfires at bay. However, if the wildfire does break 

through your first line of defense, an ignition might 

occur on your home’s exterior. The ideal situation is for 

your home’s exterior materials to prevent or retard the 

flames from burning into your interior walls, soffits, attic area, and rooms.

 Roof: The roof is the most vulnerable part of your 

home to wildfires. During a wildfire, firebrands (e.g., 

pieces of burning wood) can fall on your roof, landing in your roof’s nooks and crannies where a fire can 

easily start. Once your roof covering ignites, chances 

are good that the rest of your home will follow. The 

best way to avoid this situation is to make sure your 

roof is fire-resistant. The two main fire-resistance 

tests used today include: ASTM E108 and UL 790. 

There are three levels of classification awarded under 

the test protocol A, B, and C, with A being the most 

fire-resistant. Some treated wood shake shingle products have ratings of Class C or better. However, over 

time, the effectiveness of this chemical is reduced by 

weathering before the end of the product’s useful life 

and may leave your roof unprotected. If your roof 

needs to be re-covered, consider installing a Class A 

roof covering.

 Exterior Walls: Exterior walls are susceptible to a 

wildfire’s radiant and convective heat. A fire on an 

In a Nutshell:

Consider using materials such as Class-A asphalt shingles, slate or clay tile, metal or cement, and concrete 

products for roof construction.

Construct a fire-resistant sub-roof for added protection.

Use fire-resistant materials such as stucco or masonry 

for exterior walls. These products are much better than 

vinyl, which can soften and melt.

Consider both size and materials for windows; smaller 

panes hold up better in their frames than larger ones; 

double pane glass and tempered glass are more effective than single pane glass; plastic skylights can melt.

Prevent sparks from entering your home through vents 

by covering exterior attic and underfloor vents with wire 

mesh no larger than 1/8 of an inch.

Keep your gutters, eaves, and roof clear of leaves and 

other debris.

Clear dead wood and dense vegetation within at least 

30 feet from your house, and move firewood away from 

your home, fences, or decks.
Federal Insurance and Mitigation Administration

Rebuilding After a Wildfire

exterior wall can ‘bridge’ to more vulnerable areas 

such as eaves, soffits, vents, and windows. Wall materials that resist heat and flames include cement, 

plaster, stucco, and concrete masonry such as stone, 

brick, or block. Though some materials will not burn, 

such as vinyl, they may lose their integrity when exposed to high temperatures and fall away or melt, 

providing the fire with a direct path inside the home.

 Exterior Windows, Glass Doors, and Skylights:

Exposure to the heat of the wildfire can cause glass to 

fracture and fall out, leaving an opening for flames 

and firebrands to enter your home. This applies to 

both double pane and single pane glass, since double 

pane glass is only slightly more resistant to heat than 

single pane glass. On the other hand, single or double 

pane tempered glass 

windows, doors, and 

skylights typically fracture at higher exposures, 

well above the radiant 

heat exposures capable 

of igniting the surrounding wood.

 Eaves, Fascias, and Soffits: Eaves, fascias, and soffits are vulnerable to both firebrands and convective 

exposures; they should be ‘boxed’ or enclosed with 

noncombustible materials to reduce the size of the 

vents. Materials that melt or burn in relatively low 

temperatures, such as polyvinyl chloride (PVC) and 

vinyl siding, should not be used, since they do not 

provide adequate protection and can melt in the heat 

of the wildfire. Non-combustible screening should be 

used in the vents.

 Attic, Subfloor, or Foundation Vents: Wind and/or 

direct contact with a fire’s convective heat can push 

firebrands through the 

vents into your home’s 

basement or 

crawlspace. Your vent 

openings should be 

screened to prevent 

firebrands or other objects larger than 1/4 

inch from entering your home. Both your vents and 

screens should be constructed of materials that will 

not burn or melt when exposed to radiate or convective heat or firebrands. Also, these vents should be 

corrosion-resistant to help minimize required 

maintenance.

 Fireplace Chimneys: Windblown embers can 

access your home through your fireplace’s chimney 

flue. Once inside, these firebrands then collect on 

flammable objects, greatly increasing the chance of 

combustion. The situation can also be reversed: 

embers from your own fire can fly out the chimney 

and start a wildfire, right in your own neighborhood. 

The best way to avoid this situation is to install a 

spark arrestor made from welded wire or woven wire 

mesh with openings less than 1/4 inch wide.

 Overhangs and Other Attachments: Overhangs and 

other attachments include any additional structures 

attached to a residence such as room pushouts, bay 

windows, decks, porches, carports, and fences. These 

features are often very vulnerable to convective exposures. When assessing your home and property, if the 

feature in question is attached to your home, it should 

be considered part of your home.

Beware of Increased Flood and Mud 

Slide Risks

One of the lesser known, but critical considerations 

following a wildfire is the increased risk of floods and 

mudslides, even in areas far away from the fire.

Following a wildfire, 

charred ground where all 

plant material has burned 

away cannot absorb water, resulting in mudflows 

and floods. Properties 

directly affected by fires, 

as well as those located 

below or downstream of impacted areas, are most at 

risk, including many properties not previously considered as having a moderate or high flood risk. 

After a wildfire, it may take 3 to 5 years for the vegetation to regain the ability to intercept and retain water. 

Without vegetation and ground cover, rainfall can cause 

soil on slopes to become saturated, liquefy, and then 

flow downhill as a devastating mudflow. Residents in 

areas susceptible to flash or winter flooding, or in areas 

of extensive wildfires need to prepare in advance for 

possible flooding. 
Federal Insurance and Mitigation Administration

Rebuilding After a Wildfire

To Mitigate Against Potential Flood 

Damage in Wildfire Impacted Areas

 Use a rototiller to break up the soil surface so more 

water can be absorbed, especially in charred areas. 

 Build channels or deflection walls to direct water 

around buildings in potential mudflow areas. You can 

use silt fencing, filled bags (like sandbags), rock and 

straw bales, check dams, log grade stabilization structures, and sediment basins to control and slow water 

flow. But remember, if you divert a mudflow or any 

water and it crosses to a neighbor's property, you may 

be liable for damages. 

 Control erosion with straw mulch, hydraulic mulch, 

or other erosion control measures.

 Plant perennial plants and flowers for longer-term soil 

stabilization. Seed mixtures composed of native plant 

materials selected to complement indigenous plants is 

an appropriate long-term strategy. Plant ground cover 

on slopes and build retaining walls. 

Before the Threat of Flooding is 

Immanent, You Should:

 Evaluate your risk of flooding. Consult with your 

local planning and zoning office or engineering office 

to determine if your area is at a higher risk for 

flooding.

 Purchase a flood insurance policy even if you’re not 

in a high-risk flood zone. 

Be Prepared for All Hazards

 Review your existing insurance policy to ensure the 

limits adequately protect buildings and personal belongings and become familiar with what is and is not 

covered. 

 Make an emergency plan. Plan evacuation routes and 

keep important papers in a safe, waterproof place.

 Assemble and maintain or update your family disaster 

plan and disaster supply kit to ensure both are complete.

 Follow directions of local emergency officials.

 Visit: http://www.ready.gov for complete disaster 

planning information.

For More Information

For the most comprehensive information for communities and individuals to mitigate their wildfire risk, visit: 

http://www.firewise.org.

For information on mitigating wildfires and many other 

natural hazards, visit: http://www.flash.org or 

http://www.ibhs.org.

The International Code Council® provides a wealth of 

information at: http://www.iccsafe.org/about-icc/safety/

wildfire-safety/.

For information on homeowner responsibilities before 

and after a fire, visit: 

http://www.fire.ca.gov/education_checklist.php.

For information on flood insurance, visit: 

http://www.floodsmart.gov.