(Repost from Affordable Housing Fianance July 12, 2021 8 Must-Haves for Resilient Home Design| Housing Finance Magazine)
As hurricane season gets underway in the Atlantic and extreme heat waves batter the West, an obvious truth is worth repeating: The fundamental purpose of housing is to provide shelter from the natural world. But the reality is that as we confront a changing and volatile climate, millions of single-family and multifamily homes are unprepared for extreme natural hazards. One report found that 32 million homes in the United States are at risk from hurricanes alone.
But humans are adaptable. Think of COVID-19: Wen this invisible storm threatened homes and communities, we made changes once thought impossible. Jobs became remote, new technologies changed how we live and work, devoted commuters bought cars, and we as a society adapted to unexpected and extreme conditions. This is a lesson in resilience.
Single-family and multifamily housing used to be designed and built to consider natural weather conditions: Tall, operable windows brought in more natural light and air, color varieties improved residents’ mental health, and local building materials were chosen for their durability and adaptive qualities. Since World War II, however, housing has largely been an artificial construct, reliant on an abundant supply of mechanized systems that regulate internal temperature, humidity, and ventilation.
The United States has nine distinct climate zones determined by regional variations in climate conditions. So, why do we find the same cookie-cutter housing stock across the country?
The short answer is that as the plastics industry expanded, so did the availability of cheap house finishings and coatings. Vinyl sheathing replaced brick, and plastic replaced wood. Millions of homes made from these materials were placed dangerously in flood plains, deserts, and other at-risk areas. Now, those deserts are getting drier and those flood plains wetter, and the housing stock cannot keep up.
If we are to meet the realities of our climate future head-on, this must change. Whether designing new single-family or multifamily housing, or retrofitting existing housing, here are eight things to consider when designing a climate-resilient home:
- The home site. Knowing the distance between the site and a flood plain, a historical fire zone, or a seismic area is critical in order to understand exposure to storm surges, extreme drainage, flood path, or fire. Whenever possible, homes should not be constructed in areas that are extremely prone to climate events. Enterprise has created a free tool, Portfolio Protect, which can help developers and homeowners assess the risk to their properties from flooding, fires, earthquakes, and other climate hazards.
- Ability to reflect heat. Darker colors absorb heat and raise the temperature of the building, house, and site; lighter colors reflect and reduce heat. New-home construction should utilize lighter colors across the site, from roof to pavement to paint, so that the heat footprint is reduced as much as possible.
- Energizing the home. Overground and exposed electrical lines can severely limit power reliability during extreme weather events, as can off-site power generation. Buildings should install underground electrical lines and, when possible, should have the ability to produce power on site, through solar cells or other means.
- Conserving and promoting water health. Most water systems in the United States are delivered via central treatment service in water districts through distribution lines. When these lines fail or get damaged, or if water is in short supply, as it is in the West, households can be left without potable water. Fortifying the building’s septic system to prevent water supply contamination and collecting rainwater to reduce dependence on the wider water system can make a home more resilient in the face of climate crises.
- Sealing the envelope. In rain- and flood-heavy areas, the building envelope must be sealed securely and completely, as any leaks can allow water into the wall cavities, which can cause mold and structural damage, greatly impairing the safety of the home. Developers must take steps to seal the foundation as well to prevent efflorescence, which can cause long-term structural issues.
- Ventilating the home. Passive ventilation, such as manual-operation windows and vents, are essential to creating a climate-resistant home. Without these installed, buildings are forced to rely on mechanical cooling and heating products, which are not only more expensive but are also susceptible to failure in the event of power grid instability.
- A strong structure. It may sound obvious, but a strong building structure is an important step toward achieving climate resiliency. The continuous load path, a construction method that ties together the various parts of the house using timber, metal connectors and fasteners, and shear walls, must be free of defects and in good order. Enterprise’s Keep Safe Guide offers strategies that can be used to strengthen housing against natural hazards like hurricanes and earthquakes that have the potential to cause catastrophic structural failure.
- Efficient systems. During a weather emergency, power and water could be rationed. Constructing an energy- and water-efficient home reduces the amount of utilities consumed and increases resilience under extreme circumstances.
Too often, these critical factors are rushed or overlooked altogether in the rush to build or sell a home or apartment building. But the reality is that there is nowhere left to move that is safe from climate and weather events. Resilience in building design is no longer a luxury; it is a necessity. Lives, homes, and economies are depending on it.