architecture

Rebuilding for fire resilience

An increasingly unstable climate means rising numbers of extreme weather events, from storms and floods, to fires and droughts. Areas that had previously been safe find themselves vulnerable. Areas known to be at risk are hit again and again. That’s where resilience is so important – can we design homes, neighbourhoods and infrastructure to accomodate a changing climate? We may not be able to adapt to everything, but we can certainly reduce risk and make it easier to recover when disaster does strike.

I’ve written before about how city infrastructure can handle flooding through ‘sponge city’ approaches, or areas designed to flood. I’ve written about hurricane resistant or flood proof homes. I haven’t looked at fire resilience before, but with the recent devastation in Australia and elsewhere, it’s an increasingly important topic.

The 2018-19 fire season was particularly serious in California, with large fires in Malibu. As the rebuilding takes place, there’s an opportunity to incorporate new resilience and sustainability features for the future. The environmental consultancy Terrapin Bright Green has been working with communities in Malibu, and they have released a report on rebuilding for resilience. While it’s written specifically to support Malibu, many of its recommendations are broadly applicable in other places.

There are aspects of fire resilience that can’t be retroffited and can only be applied in building or rebuilding – such as the orientation of the building or its location on the site. There’s a science to this that has to take in the local geography, considering the fact that fires move faster uphill for example, or orienting the home to reduce exposure to the prevailing wind.

Homes catch fire in four main ways during a wildfire, and the design of the building and the landscaping around it can reduce the risk for all of them.

Wind-blown embers falling on homes is the most common cause of ignition. Architects might want to consider simpler roof lines and building contours that don’t trap embers. Reducing the number of windows and openings on the windward side can prevent embers from building up, and underfloor spaces and decking need to be enclosed so embers don’t get underneath. Well located stone walls or planting at the edge of a property can help to screen the home and catch embers before they get too close.

Radiant heat can also ignite homes, and this risk can be reduced with non-combustible materials and good thermal insulation. As Terrapin highlight, some of the best practice for efficiency also helps with fire resilience – such as airtight building envelopes, as few vent openings as possible, and attention to detail on thermal bridging. A well insulated home will keep heat in when it’s cold, keep it cool when it’s hot, and slow the transfer of heat during a fire.

Direct flame contact is almost impossible to protect against, which is why it’s so important to design landscapes and gardens to ensure that flames never reach the building itself. Guidelines in all fire-prone areas recommend removing trees too close to buildings, leaving sufficient gaps between any potential dry vegetation and the home, and maintaining a ‘defensible area’.

Fire-driven wind is the fourth factor. Large fires create their own weather, including winds strong enough to fell tress and take roofs off. It’s hard to defend a home from this kind of force, but porches, decks and overhangs can be vulnerable spots – anything that the wind get can get a hold of. Build quality is also paramount here. Stronger and sturdy homes will be able to resist higher wind speeds.

Build quality is something to pay attention to in any disaster recovery. When a whole community has been devastated, there is a temptation to take shortcuts and re-house people as quickly as possible. There’s often political pressure to deliver, construction companies are incentivised to work fast, and of course everybody wants to get back to normal as soon as they can. But if that means cheap and cheerful homes, that might just create more vulnerability later. Terrapin recommend modular home building as a response – quicker to assemble on site, but still built to a high standard.

Another thing Terrapin have been advising Malibu residents to consider is greater self-sufficiency. Rebuilding is an opportunity to reduce reliance on utilities, and this is another area where resilience and environmental performance can double up. Homes can be built with solar panels and energy storage, making them less vulnerable to power cuts. Rainwater capture and storage makes homes more resilient to dry spells in general. And of course, homes can be designed and rebuilt without a connection to the gas grid. A fully electric home is lower carbon and eliminates a potential fire hazard.

Finally, fire resilience isn’t just about homes, but about community. Strong neighbourhood networks make a real difference in an emergency. Communities that are rebuilding often experience a powerful sense of unity and purpose, and that can be a good moment to develop plans for the future, identify the most vulnerable, and working out how to share information and get organized when disaster strikes.

As fire seasons extend and more regions begin to suffer the effects, we will need to pay more attention to good practice in rebuilding, and learn from places that have done it well. And when it is done well, post-disaster reconstruction can deliver excellent homes that are more efficient as well as more resilient.

3 comments

  1. It’s worth noting though that in a lot of places like Australia heatwaves kill significantly more people than all other natural disasters put together.

    So while we definitely can have homes to cope with bushfires AND heatwaves, the priority would ideally be heatwaves. However bushfires are a lot more emotive so they get more attention.

    (I used to work on a climate change project for the Australian Red Cross) 🙂
    Cheers, Dani

      1. Great point that’s it’s Europe and probably most of the world.

        Heatwaves get so little media attention, and when they do it’s all sunbathing and ice lollies. Fun in the sun rather than the true danger to health.

        Ps. I love your blog. I grew up near Leighton Buzzard and worked in Luton for a couple of years so it’s great to see what’s going on at home 🙂

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: