DESIGN FOR CLIMATE CHANGE: How to Design a Fire Resistant House to Protect Your Home from Wildfire

Updated: Jun 11

Unless you live in the middle of a large city, there is a growing risk of your home being destroyed by a wildfire in the next few decades. That's a bold allegation that sounds like pessimistic, wild speculation; but recent history here and abroad point to that scenario as an eventuality rather than a remote possibility.


house engulfed in flames Hillside Fire
A house is engulfed in flames during Hillside Fire 2019; photo credit Noah Berfer Associated Press

However, with the right design and construction, you can give your home a great chance of withstanding a wildfire.

Contents:

Part 1: The Interface

Should British Columbia Worry About Interface Wildfires?

How Do BC's Interface Areas Compare?

The Australia Problem

The Australia Solution - Site Assessment

Wildfires Are Coming to British Columbia (Actually They're Already Here)

BC FireSmart

Urban Fires - Your House Isn't Safe from Fire in the Middle of the City

Part 2: How to Design and Build Fireproof Homes

The Fireproof House

Building Form

Structural Materials

Cross-laminated Timber Panels (CLT)

Siding Materials

Mineral Fibre Insulation

Building Features

Automatic Sprinklers

Conclusion: The Hardened Home

Protect Your Home, Protect Yourself

Summary: Key Elements of the Ultimate Fire-Resistant House


Part 1: The Interface

Wildfires in BC are growing in frequency, size, and intensity. As suburban development encroaches directly into previously wild land instead of being preceded by agricultural development, many homes are exposed to the natural cycle of forest fires. This area of exposure is referred to as the wildland-urban interface (WUI); I will refer to it simply as the Interface.


Should British Columbia Worry About Interface Wildfires?

Look through the Google satellite images below of some recently-developed or newly-expanded areas and note the Interface.


Mission, BC:

Google satellite photo of Mission, BC

Maple Ridge, BC:

Google satellite photo of Maple Ridge, BC

Coquitlam, BC:

Google satellite photo of Coquitlam, BC

Anmore, BC:

Google satellite photo of Anmore, BC

North Vancouver, BC:

Google satellite photo of North Vancouver, BC

West Vancouver, BC:

Google satellite photo of West Vancouver, BC

South Surrey, BC:

Google satellite photo of South Surrey, BC

Sooke, BC:

Google satellite photo of Sooke, BC

Royal Oak, BC:

Google satellite photo of Royal Oak, BC

West Kelowna, BC:

Google satellite photo of West Kelowna, BC

Southeast Kelowna, BC:

Google satellite photo of Southeast Kelowna, BC

Why should we be concerned with these Interface developments? These residential neighbourhoods are situated next to metaphorical powder kegs.


photo of forested mountain ablaze and lone house being attacked by large flames
photo credit: BC Wildfire Service

Over the course of the twentieth century, public policy cemented its position to suppress forest fires to protect developed land. The result is an accumulation of deadfall - vegetation that dies and simply piles up on the forest floor - and densification of forests - tree canopies becoming increasingly contiguous. The deadfall accumulation provides a greater source of fuel for any wildfire, and the closed tree canopy helps fire travel above ground. Behaviour of forest fires is understood, so it's useful to look at other regions which have already experienced for some time these deteriorating conditions and begun to address them.


Wildfires are Consuming California and Its Suburbs

House surrounded by forest, engulfed in flames during 2020 Oregon wildfires

Across the US, the most damaging wildfire seasons have been in recent years, including 2017, 2018, and 2020, accounting for 62% of the structures lost over the last 15 years. California has suffered perhaps the most. In 2017, Northern California suffered a number of very large and intense forest fires - two of which were the Tubbs Fire, the most destructive in California's history at the time, and the Thomas Fire, the new record-setting fire the same year. The Tubbs Fire swept through the Fountain Grove and Coffey Park neighbourhoods in the North end of Santa Rosa, California and destroyed nearly every single house. Fountain Grove and Coffey Park are adjacent to rural and undeveloped areas but themselves are fully developed suburbs. Here is an overlay of this part of the Tubbs fire encroaching into Santa Rosa.

annotated Google satellite photo of Santa Rosa, CA showing South end of Tubbs Fire of 2017 encroaching into Fountain Grove

Here is a satellite split view showing Fountain Grove before and after the Tubbs fire.

annotated Google satellite photo of Fountain Grove in Santa Rosa, CA showing ground conditions prior to 2017 Tubbs Fire and ground conditions as of 2021

In the lower half of the image, you see orange and brown patches. Here's a zoomed-in view that reveals these patches to be the bulldozed footprints of what used to be houses.

Google satellite photo of a cul-de-sac in Fountain Grove, Santa Rosa, CA after Tubbs Fire 2017 showing bare land after houses were removed

Immediately after the fire, the houses were obliterated, and the neighbourhood resembled a warzone.

aerial photo of Fountain Grove neighbourhood of Santa Rosa, CA, several days after houses were destroyed by Tubbs Fire 2017
photo credit: John Burgess/The Press Democrat

The neighbourhood of Coffey Park was similarly razed when the fire rolled into town; the graphic below illustrates the buildings destroyed.


map graphic of Coffey Park, Santa Rosa, CA, marking houses which were destroyed by the 2017 Tubbs Fire

Below is a photo from the day after the fire.

aerial photo of destroyed houses in Coffey Park neighbourhood in Santa Rosa, CA, a few days after 2017 Tubbs Fire
photo credit: California Highway Patrol/Golden Gate Division via Reuters

Google satellite photo of Coffey Park neighbourhood in Santa Rosa, CA, circa 2021 showing new construction

Above is a satellite image overview of Coffey Park a few years after the fire. All of the houses you see are brand new or under construction. The small yellow areas are sites on which the floor slabs are being poured (the yellow is a vapour retarder membrane that lays under the slab). The tan-coloured areas are the plywood of new roofs which don't yet have membrane or shingles installed. The satellite view below shows this more clearly.


Google satellite photo of two blocks in Coffey Park neighbourhood in Santa Rosa, CA, circa 2021 showing new houses and houses under construction

Prior to 2017, Fountain Grove and Coffey Park were like any other suburban neighbourhood - kids playing, families barbequing, everyone feeling pretty safe. Nonetheless, these neighbourhoods were decimated.


The 20 most destructive wildfires in California's recorded history are listed below. Notice that 11 of the top 20 have occurred in the past five years. Notice also that three out of four of the most damaging fires - as measured by the number of structures destroyed - also have happened in the past five years.


Table listing California's most destructive wildfires ranked by area burned; the top 7 fires are highlighted and all occurred 2017-2020
data source: wikipedia.org


photo of house engulfed in flames during Camp Fire 2018, California
A house is engulfed in flames during Camp Fire 2018; photo credit: AFP


house is engulfed in flames during Dixie Fire 2021
A house is engulfed in flames during Dixie Fire 2021; photo credit Ethan Swipe / Associated Press

How Do BC's Interface Areas Compare?

If you're considering building a house in an Interface area in British Columbia, Coffey Park and Fountain Grove are reasonable predictors for what is likely to happen to any of the Interface areas in British Columbia. The BC wildfires of 2021 have shown that the Okanagan and the Kootenays are the most vulnerable due to being surrounded by uninterrupted expanses of semi-arid wildland. However, two factors have maybe bought a little time for homes in BC Interface zones:


First, BC generally receives more rain than California and is not in the middle of a large drought. California's most concentrated period of drought for the past two thousand years has been in the past 50 years (see the tall red smudge at the right end of the graph below):


graph illustrating alternating cycle of drought and over-wet in California since year 0; heavy smear after year 2000 indicates more drought
data source: drought.gov/states/california

The worst period so far ran from 2014 to 2017 and is believed to be the reason for the severity of the 2017 fires:


graph showing duration of different levels of drought in California since year 2000; intense periods indicated between 2014-2017 and after 2021
data source: drought.gov/states/california

British Columbia has not seen extended droughts in recent history, but that is expected to change.


Second, most development in British Columbia is along shorelines, in deltas, and at the foot of mountains. In contrast, many developments in California occur well up hillsides and at the tops of ravines and canyons. This is an important distinction: wildfire usually travels uphill much faster than it does downhill. However, unless actively fought, it WILL travel downhill especially with a wind that carries embers - a large part of how wildfires travel.


The Australia Problem

If developing into the Interface creates a risk of entire neighbourhoods lost to wildfire, what is the solution? Australia has larger areas of undeveloped wildland and has been experiencing more protracted drought longer; just over a decade ago, it enacted legislation to address the increased risk. Ranking the top regional fires worldwide on record for the past 150 years, it reads like a tragic leaderboard with Australia taking many of the top spots. Also of note is that these are nearly all in the past 20 years.


Table listing 14 largest wildfire seasons or fires on record worldwide; earliest listing is 1871; California listed 4 times; Australia listed 6 times including the top 2 listings
data source: wikipedia.org

Historically over the past 150 years, Australia has seen an increase in both the area of bushfires and the number of buildings destroyed. The number of buildings lost is partly a result of development encroaching into previously wild territory.


Graph illustrating Australia's largest fire events on record since 1851; larger events visibly more frequent since year 2001
data source: wikipedia.org

Graph illustrating Australia's most destructive fire events on record since 1851 (measured by structures destroyed); most damage occurs since 1991
data source: wikipedia.org

The 2002-2003 bushfire season was Australia's most destructive on record, apart from an outlier season 1974 in which an overabundance of grass produced by heavy rains that year. Australia was ravaged again in the 2009-2010 bushfire season which peaked one Saturday in February and hence is referred to as the Black Saturday Bushfires. Most recently, the bushfire season 2019-2020 gained much publicity worldwide with a parched koala as its poster child.


The Australia Solution - Site Assessment

Spurred by the Black Saturday tragedy in which 173 people died, the Australian government revised the building construction standard AS3959 to apply the Bushfire Attack Level (BAL) rating more holistically to all residential buildings. This approach assesses the risk to which a building is expected to be exposed depending on the individual site and conditions such as vegetation type and density, and slope of land. Properties are assessed and given a BAL rating by inspectors.


Australia's national building code sets minimum performance standards for construction on a property with a given BAL rating; it does not prescribe exactly how the building must be constructed nor does it require fireproof houses. While this approach provides flexibility for innovative solutions, it can be confusing for homeowners and does require some expert consultation.


Wildfires Are Coming to British Columbia (Actually They're Already Here)


motorist watching mountainside on fire in BC
photo credit: THE CANADIAN PRESS / Darryl Dyck

I've showcased the Australian and Californian histories to illustrate the risk and likelihood of your house burning down in a wildfire. British Columbia's severe wildfire phase is still in its early years, but the combination of suburban development and impending drought conditions puts it on the same track with a similar outcome unless something is changed.

More people in BC are looking into how to build fireproof houses now than ten years ago, and that's a good thing; it shows an awareness of the growing problem. 2017 and 2018 were the most destructive in BC so far. Drought conditions continue, and 2021's extensive damage makes it a contender for setting a new record.


table listing total area burned for each fire season in British Columbia since 2010; 2017, 2018, and 2021 exceed other seasons' area by 5-10x
data source: wikipedia.org

“Even if we were able to turn back the dial on climate change we would still have wildfires that are severe and would burn people’s houses down,” said Jesse Zeman, director of fish and wildlife restoration with the B.C. Wildlife Federation. Additionally, studies of British Columbia's past drought conditions point to more severe droughts in the next 50-100 years. The stage is set for large, vicious wildfires in BC; new ideas for wildfire-resistant construction of houses are needed.


BC FireSmart

Forest fires used to occur more frequently before the 19th century; this natural cycle (10-30y) has been halted, and the result is larger more destructive fires. “Fire inoculated the landscape against large fires,” Chilliwack-based wildfire ecologist Robert Gray. Instead of continuing to rely on firefighting efforts, we can design properties to reduce the likelihood that they contribute to a fire.


In 1990, led by the Alberta Forest Service, a committee of Alberta and Canadian Parks departments formed to address common concerns about wildfire in the Interface created Partners In Protection - an agency when subsequently developed the FireSmart Canada program. In 2017, the BC Wildfire Service organized the British Columbia FireSmart Committee (BCFSC) to build a FireSmart program specific to BC. BCFSC develops and delivers the FireSmart program which includes educational material to help homeowners and communities lessen the risk that wildfire poses to their properties.


A large part of the guidance consists of reducing the amount of vegetation and other fuel around the house. The BC FireSmart Manual identifies four "Priority Zones":

  • Noncombustible zone is the first 1.5m (5') out from your house - no combustible elements or landscaping

  • Zone 1 extends to 10m (30') - small shrubs and grasses

  • Zone 2 extends to 30m (100') - no coniferous trees

  • Zone 3 extends to 100m (300') - thinned tree spacing

The manual also provides guidance on simple, economical measures that a homeowner can take such as eliminating concealed spaces for embers to enter or possibly replacing some elements such as siding with wildfire-resistant construction. The BCFSC guidelines focus on practical changes that can be made with minimal cost. They balance the benefit of wildfire resistance with the cost of various measures that can be taken. However, they're not expected to eliminate the risk altogether.


The high temperature and the amount of heat generated devour and raze whole houses in less than a few minutes. In some cases, a whole town can be lost in under half an hour. The small town of Lytton was a "Recognized Neighbourhood" by the FireSmart Canada program. Lytton hit a Canadian temperature record of 49.6 C the day before a wildfire erupted there on June 30, 2021, destroying approximately 90% of the community despite being flanked by a river on two sides.


aerial photo of Lytton, BC showing roughly 90% of the buildings destroyed by the Lytton Creek Fire 2021
photo credit: THE CANADIAN PRESS / Darryl Dyck

The ferocity of the wildfire that razed Lytton was due in part to high winds fanning flames and spreading embers and in part to extremely dry conditions. The plateau was not heavily vegetated, but the fire tore rapidly through the town. Glowing embers can be carried as much as 2km ahead of a fire or possibly more depending on the wind conditions. The resulting firestorm would not be greatly hindered by simple measures such as reduced combustibles near the house, and in urban or suburban areas it is not possible to create the recommended space anyway. FireSmart guidelines are not designed for suburbs, and the result can be as disastrous as the horror of the Camp Fire that gutted Paradise, California, in 2018.



satellite photo of smoke plume from Camp Fire that attacked Paradise, CA in 2018
photo credit: Earth Observatory / NASA

Google satellite photo of Paradise, CA after Camp Fire of 2018

Roughly 95% or more of the houses in the photo above are gone. Here's a closer look.

Google satellite photo of Paradise, CA after Camp Fire of 2018 showing roughly 7 blocks x 7 blocks

Closer still... and nearly ALL the houses are like this - piles of rubble.

Google satellite photo of Paradise, CA after being destroyed by Camp Fire of 2018 showing rubble on every home lot

FireSmart techniques are economical measures to impair the spread of fire, but in the face of severely dry conditions and a voracious wildfire, we need to revisit how the houses themselves are designed and built. The house's construction is the last line of defense against fire in a rural area, and it is the only line of defense in a suburban or urban area.


Urban Fires - Your House Isn't Safe from Fire in the Middle of the City

Let's say you're over at your neighbour's place for a housewarming barbeque. The watermelon slices are on the table but covered up, the corn on the cob are waiting, and the marinated chicken is on the grill. Your other neighbour's house is still under construction, and it's still bare exposed wood. One of the workers is using a heat gun, holds it too long in one place, and the adjacent plywood starts burning. You and your buddy have coolers in hand, are chatting away, and don't notice until the entire structure catches fire a minute later. The flames take over the roof and jump over to your house by the time you get the garden hose out. They've already started consuming the next house over. Three minutes later, the whole side of your house is on fire. Two minutes later, the flames have burned through the siding and reach the structure. Your house is on fire. Sound far-fetched? Here's the video.

Or maybe the other houses weren't under construction... same result:

This is a deadly nightmare that turns real for numerous people every year.

In 2016, a wildfire that started 15km outside of For McMurray, Alberta. 3244 structures were destroyed, and the burned area was 590,000 ha. The extra challenge with that fire was that it continued to smolder over the course of the winter and wasn't declared extinguished until August of 2017.

Part 2: How to Design and Build Fireproof Homes

In North America, residential construction four storeys or less - and recently some taller residential buildings - are constructed of lumber, wood joists, and plywood. Although there's usually insulation in the framing space, the whole arrangement of wood acts not much differently than a stack of kindling during a fire. It doesn't matter if it's a 60-year-old Vancouver Special or a newer, $30 million dollar mansion, chances are that the bones of your house are the same - a bundle of sticks. Some luxury homes are made of concrete (more on that below), but there is a better way.


The Fireproof House

Sorry to burst your bubble, but no building can be 100% fireproof. Large buildings, tall buildings, and other buildings intended for use by the general public are designed to limit the spread of fire and smoke, but even their exit systems and internal separations are designed to perform for only 1 or 2 hours in most cases, 4 hours in less common situations.

After the layout of your property, the house design itself dictates how it will perform when exposed to a fire. Using wildfire-resistant materials is a big part of attempting to create fireproof homes, but wildfire-resistant construction incorporates building form, building materials, and features to determine its resistance.


Building Form

The shape of a building should be considered when designing a fire-resistant home.

  • A compact, simple form has less surface area and therefore offers less opportunity for flame or embers. A house with many corners presents more opportunities where fire can take hold. For example, a house with an H-shaped or U-shaped floor plan is more susceptible than a house with a rectangular floor plan.

  • The slope of the roof is also a factor in the rate of fire spread. Flames climb up pitched roofs far more quickly than across flat roofs. However, embers that land on a steeply-pitched roof are more likely to roll off than to burn into the roofing material where they land.

  • Projections such as eaves, overhangs, porches, bay windows, and integrated decks all present additional points - typically combustible ones - where fire can start.

Structural Materials

Nearly every house has a wood structure - typically dimensional lumber. Large buildings and commercial buildings are required to use noncombustible building materials to significantly reduce the likelihood of a fire in the building destroying the structure.


Two costly alternatives to lumber structure are concrete and steel since each is a fireproof material. However, the added weight of concrete or even steel necessitates MORE supporting structure. That equates to higher construction cost, fatter columns, and less opportunity for large, uninterrupted glass walls. Concrete construction and steel structures take longer to build, and they increase the complexity of construction sequencing. Concrete and steel are both more expensive materials whose energy-intensive production requires devastating minerals extraction, creates significant water pollution, and gives off a large amount of greenhouse gases.


Some people think that if you build a concrete house, it will be safe from fire. Buildings with concrete construction can still be burned out. Even if you build a concrete wall, fire will enter through the windows, doors, and other openings. If you do decide to use concrete - as some luxury homeowners have - understand that while the structure itself may be largely immune to fire, everything else is not. Fire will still enter through the doors and windows and will consume most of the interior. The cost increases for construction could make rebuilding the interior as much as the entire original construction cost. Commercial and public buildings are required to be constructed of concrete or fireproofed steel NOT to prevent the building interiors from being destroyed but to ensure that the structure and the exits remain intact long enough for occupants to evacuate the building.

Remember: the structure of Grenfell Tower was concrete. Grenfell Towers was a 1974 concrete high-rise recently renovated, and it still burned down.

Grenfell Tower shortly after fire which gutted the building was extinguished

In the Netherlands in 2008, the TU University of Delft, Architecture Building - 13-storey 1970 reinforced concrete building burned down in 2008.

You may have seen a number of articles advocating the use of insulated concrete form (ICF) products. These products have been around for over 60 years and being radically different from traditional residential construction were not readily adopted by home builders. As energy efficiency requirements have been raised in building codes and people also have turned to concrete, ICF has recently gained support by builders who understand its benefits. However, the primary component of these products is Styrofoam - a combustible material.

Another option for building the exterior walls is a structural panel comprised of foam insulation sandwiched between concrete facing layers. Two examples are TridiPanel and Nexii The panel itself is highly thermally efficient in the middle, but there is very low insulating value at the joints. As well, water or fire may enter any small penetration of the exterior facing and compromise the entire panel.


Cross-laminated Timber Panels (CLT)

mid-construction photo of residential building interior showing exposed CLT panels used for roof, walls, and floor

A structural alternative is "mass timber" or "heavy timber", and it is significantly different from lumber construction. Technically, mass/heavy timber construction has been around for over a century or two, but a comparatively recent innovation that has taken firm hold in Western Europe - where the traditional structure was brick or stone - is called cross-laminated timber (CLT). CLT is a shop-fabricated product consisting of wood studs laid beside each other, in multiple layers. The panels can be used as roofs, walls, or floors. Because the CLT is fabricated in a shop, it eliminates most of the waste and mess on a typical construction site. The fabricators work in a controlled environment, so the product is more precise and uniform. A CLT panel can span typically double the distance that lumber joists can span and therefore eliminate some supporting walls or columns and improve the openness of a space.


photo of 3-layer CLT panel specimen after fire test showing charred face

Another important advantage of CLT construction which is taken into significant account in recent updates to building codes is its resistance to destruction by fire. As with any other wood, CLT does burn. However, as it burns, it is converted into a black, mostly noncombustible material called char. Char is a poor conductor of heat comprised of essentially just carbon. With adequate thickness, CLT and other forms of heavy timber or mass timber retain adequate structural capacity during a fire. The char layer interferes with the combustion of the wood not directly exposing the fire and slows the burning of additional wood until an adequate thickness has developed at which point burning effectively stops. Heavy timber framing such as was used in warehouses in the late 19th century or in log cabins also undergoes the same charring process.


Be aware that ALL materials will burn or disintegrate if the temperature is high enough. A normal property fire can develop temperatures around 800°C at the ceilings.

  • Steel melts around 1500°C but will begin to deform and collapse at around 400°C.

  • Concrete begins to disintegrate around 600°C

  • Typical construction brick fails around 600°C

  • Special fire brick begins to fail around 900°C

In comparison, a fire test in 2019 studied a CLT floor panel exposed to a 900°C fire for an hour. The burning face of the panel reached and plateaued at a temperature of 700°C. Wood at a depth of 3/4" into the panel plateaued at 100°C, and the unexposed side never increased above 20°C. CLT isn't a magic material; it is the form and detailing which result in this defensive charring behaviour during a fire.


To improve even further the CLT resistance to fire, a configuration locally called encapsulated mass timber can be designed. A thin, concrete topping is poured on the top of floor panels, and fire-rated drywall is secured to the underside of floors and roofs. Columns and walls are also clad in fire-rated drywall.


Earth Structures

Made onsite with primarily soil and water, earth blocks emerged in the 1960s as an energy-efficient and eco-friendly means of construction. Barbato and colleagues have been working to understand and improve earth block performance for all manner of climate and disaster challenges. (ucdavis.edu)


Rammed earth is another earth-based structural system. The thermal mass is a buffer against the heat of a desert climate or against the heat of a wildfire.

photo of Nk'Mip Cultural Centre rammed earth exterior wall
Nk'Mip Desert Cultural Centre

Hempcrete

A unique home that generates more energy than it uses, was built on a hillside property in Sooke, BC. “We tried to create the most sustainable, safest, most energy-efficient and least toxic home possible,” owner Arno Keinonen said. The walls were constructed of building blocks made mostly of hemp, lime and water. “It's a marks and tendon joint that forms a structure for the load of the building.” The blocks are a new product manufactured in Calgary; Keinonen's Vancouver Island home marked their first test run. (globalnews.ca)


Siding Materials

Many options for fireproof materials are available when deciding on exterior finishes. A big key to the fire-resistant home is the material choice for wall cladding and roof finishes. Vinyl siding has a fairly low melting point. When it ignites, it will act as a fuel for the fire and bring the flames up the exterior walls to the roof. Vinyl also produces toxic smoke when it burns. On the West Coast, wood - often cedar - is a favoured siding material due to its local abundance. Tall residential buildings that are permitted to be constructed of wood still have a restriction on the siding material to prevent a fire from one part of the building popping out the window and racing up the building to burn out all the floors above. The Grenfell disaster was a result of similar requirements not being met correctly despite the building being constructed of concrete.


When choosing a siding material for a house, you may not be thinking about a brick wall as an option. However, bricks are available in many colours, various finishes, and even a few different sizes.

  • A common example of a noncombustible material is brick. Brick is available in an enormously diverse range of colours and styles.

  • Stucco is another common material, but note that only the traditional three-coat cementitious stucco is noncombustible. Acrylic stucco and EIFS are both combustible and do not offer any protection from fire.

  • Cement or cementitious panel and plank products such as Öko-skin, Hardie, Nichiha, and Synstone are offered in a range of colours, textures, finishes, and sizes. They are commonly used on multifamily buildings but can just as easily be used on a house.


  • Metal siding is typically found on commercial buildings but also on some high-end custom houses and provides a more contemporary appearance


Shou Sugi Ban

  • While not technically noncombustible, a method of treating wood siding produces a charred, fire-resistant product called shou sugi ban. It is a material originally developed centuries ago in Japan to provide improved resistance to fire, to rot, and to rain. Some suppliers can produce it in a range of colours, but different treatments will have varying resistance to flame spread.

photo of shou sugi ban blackened planks at building corner

photo of shou sugi ban scorched planks at building corner

Below are some samples of the wood products from Poco Building Supplies processed similarly to shuo sugi ban.



Stone

Stone cladding has become increasingly popular over the past few decades and is available in numerous colours, styles, and configurations.

Mineral fibre insulation

Another key material to consider when designing a fire-resistant home may surprise you. More residential buildings in BC are built to have insulation between the structure of the walls or roof and the siding material. Traditionally and even still most commonly today, building insulation is located between the wall studs and located between the roof joists or trusses. However, insulation that is sandwiched between the structure of the wall or roof and the exterior cladding material is the most effective at preventing heat transfer. Even using fire-resistant materials for the cladding and for the wall or roof structure, the right insulation can act as a fire blanket if embers or flame breach the protection of the siding material.


A builder may tell you that the most effective thermal insulation is rigid foam (plastic) boards such as polystyrene (Styrofoam/EPS/XPS) or polyisocyanurate (boards or sprayed). While those materials provide greater thermal insulating value for a given thickness, there are disadvantages that undermine the material advantage.

  • rigid board materials don't conform to the inevitable irregularities of the surface on which they're installed; that intermittent gap can trap rainwater which will eventually leak inward

  • rigid insulation boards don't accommodate imperfect joints; these gaps are therefore uninsulated locations that lose interior heat or

  • sprayed insulation shrinks and cracks after a few years; gaps result and compromise the insulation the same as rigid boards

  • polyurethane, polystyrene, and polyisocyanurate are petroleum-based products (boards or sprayed) are highly combustible and they will emit toxic fumes in the event of a fire.


An excellent solution that has been used extensively in commercial and institutional construction for a variety of reasons is mineral fibre insulation. It is produced in a variety of thicknesses, densities, and formats. The most common product is Rockwool (formerly Roxul).


Building Features

People trying to build fireproof houses think first of fire-resistant materials, but exterior features must be reviewed also. Some could be changed to create less of a fire hazard or be omitted altogether. Most features are constructed of flammable materials - either wood or plastic.

  • Avoid Decks: Many people want beautiful wood decks, but from the perspective of a wildfire a deck is merely a scaffold upon, around, and under which flying embers will plant themselves and start new fires.

  • Doors and Windows: Although glass itself does not burn, it is prone to shattering when the temperature one one side is far different from the temperature on the other side. Double-glazed windows handle this temperature difference much better, and triple-glazed windows perform even better than that. Furthermore, tempered glass is more resistant to the stress of extreme heat on one side and is therefore less likely to shatter and allow embers or flame to enter. Doors which have no windows in them should also be of the fire-rated type wherever possible.

  • Fire Shutters: Noncombustible fire shutters protect doors, windows, and other openings from fire. Fire-rated overhead coiling shutters are frequently used in large buildings, but fire-rated shutters are available for houses also. Even a non-rated swinging or sliding shutter if well designed can deflect most of the radiant heat and prevent fire entering through the openings.

  • Gutter Guards: Leaves and twigs collect in typical eavestroughs and gutters and therefore need to be cleaned out to allow proper drainage. However, as it builds up, this dry vegetation becomes a source of fuel for embers. A gutter leaf-guard or perforated / screened cover prevents leaves, twigs, and even embers themselves from accumulating.

  • Landscape Break: Although not technically a part of the house, the zone immediately adjacent to your house can either be an immediate additional threat if it contains combustible material or vegetation or be a reprieve from the volume of hot air and fire.

  • Spark Arrestors: A metal or stone lid on the top of your chimney and metal mesh in the openings can prevent sparks or embers from flying out if you have a fire in your fireplace or from flying into the house from a nearby wildfire.

  • Closed Soffits and Crawlspaces: Soffit vents, attic vents, and crawlspaces must be fitted with tight metal mesh to prevent embers from entering the concealed spaces in the building while still allowing the necessary venting of moisture buildup.

  • Airtight Construction: This aspect has less impact than other features, but it does matter. In commercial and public buildings that have interior fire-rated walls, the doors are fitted with special seals that prevent smoke from passing from one side to the other. In addition, along the bottom there is another somewhat airtight seal less to block smoke - which accumulates from the ceiling - and more to prevent air (oxygen) from being sucked into - and fueling - the fire. By preventing the leakage of air into

Automatic Sprinklers are a Workaround

Modern automatic fire sprinkler systems are generally very effective at putting out or at least reducing the severity of a fire until firefighters arrive. If you have one, that is. A number of municipalities in the BC Lower Mainland require new buildings - including houses - to be designed with automatic fire sprinkler systems and sometimes fire alarms. A fire alarm is triggered by someone pulling it, by smoke, or by fire a sprinkler head that has been set off. By the way, what you've seen in movies is wrong; the sprinkler heads don't go off all at once. Each fire sprinkler head will go off only if the temperature at that head is high enough. One or two sprinkler heads will often put out a small fire before it becomes a big one.

An automatic fire sprinkler system does need to be designed and installed correctly. Any renovations must ensure that there's still adequate coverage. The systems also require periodic inspection and maintenance. Water pressure must be adequate at all times. More noticeably, the water spraying from the heads must not be blocked by boxes or anything else piled up or built in front of the heads. Of course, if your house has no sprinkler system, you don't have this protection.


Installing an automatic sprinkler system may not always be feasible or even possible. The system requires an adequate water supply with enough water pressure. For locations with a limited or decentralized water supply, you would require a fire pump, a backup emergency generator (kept fueled and maintained yearly) to run the fire pump, and likely a nearby large body of fresh water.


Conclusion: The Hardened Home

Prepare for wildfire and harden your home now. There are three ways your home can be exposed to wildfire: direct flames from a wildfire or burning neighboring home; radiant heat from nearby burning plants or structures; and flying embers. Flying embers from a wildfire can destroy homes up to a mile away and are responsible for the destruction of most homes during a wildfire. It is possible to increase your home's chances of survival if you take the necessary measures.


Protect Your Home, Protect Yourself

Very few people are worried about their house catching on fire, but every single person who loses their house in a fire regardless of the cause feels devastated. Insurance policies typically cover less than what people assume they do. The cost of construction to rebuild a home in BC is far more than it was when the house was built, and that's guaranteed in light of continual price escalation over the past decade. The cost to put together a big chunk of your life is even greater.

"More than 200,000 people living in wildfire-prone areas received notice in 2019 that their insurance carrier would no longer be covering them. Too risky. There's a moratorium on those non-renewal notices now, but the threat of insurance loss remains for millions of people." (ucdavis.edu)

Your house could become a pile of char and ash a week after you move in. Give it a fighting chance.


Summary: Key Elements of the Ultimate Fire-Resistant House

  1. Compact, simple form

  2. CLT structure

  3. Rockwool exterior insulation

  4. Noncombustible wall and roof exterior finishes

  5. Fire shutters

  6. Tempered glass windows

  7. Screened openings (vents, chimney, crawlspace)

  8. Noncombustible landscaped perimeter


diagram of key characteristics of fire-resistant house construction

One can never guarantee that your house won't burn down, but you can choose strategies and materials that can greatly reduce the risk and likely save your home and your investment from destruction. You're not invincible - just far better prepared than everyone else. In my work with commercial and multifamily buildings, I've researched products, systems, and certifications to satisfy stringent flame spread and fire-resistance requirements far beyond what are typically involved in most residential construction.


I have used a wide range of materials from which I present options to suit your needs, and I develop construction assemblies, forms, and details that provide a high degree of resistance to ignition, to burning, and to flame spread. Although no building could ever be rightfully claim to be fireproof, you can have greater confidence in a building of my design if - when it faces a wildfire.


If you're considering a renovation or a new construction of a house or a multifamily building and are interested in greater security from urban or wildfire, I can tell you more about your options.