Choosing Resiliency: Lessons from Hurricane Michael

In this post, Doug Allen, P.E., a structural engineer with Simpson Strong-Tie, looks at the choice homeowners in disaster-prone areas face between simply building to code and building to standards of resilience or IBHS FORTIFIED Home™ standards instead.

Resilience, or resiliency: The capacity to recover quickly from difficulties; toughness. The ability of a substance or object to spring back into shape; elasticity.

In the wake of the most recent and very devastating hurricane seasons, the theme of structural resiliency has resurfaced with renewed urgency for increasing numbers of homeowners, builders, Designers and civic planners. Hurricanes pose a triple threat of high winds, substantial rain and storm surge. Extreme weather has cost the nation nearly $100 billion in damage during 2018. Accordingly, awareness has risen within affected and surrounding coastal regions regarding their communities’ existing structural resilience ratings (low or high) and the need to improve in view of the losses as well as the time and cost to rebuild what was destroyed.
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Habitat for Humanity Introduces Habitat Strong Program

You’re probably already familiar with Habitat for Humanity, a nonprofit builder of simple, decent and affordable homes for low-income families around the world. According to builderonline.com, they were the 15th-largest builder in the country in 2015 when ranked by number of closings. Simpson Strong-Tie has been an official national partner with Habitat for Humanity since 2007, making contributions of cash and products exceeding $2.5 million in that time, and Simpson Strong-Tie employees have spent hundreds of hours building homes and training local Habitat affiliates.

Habitat for Humanity Home

We know from working on Habitat houses that they tend to be well built. There were newspaper articles about Habitat houses performing better than neighboring houses in Hurricane Andrew. In an effort to better benefit the homeowners they serve, Habitat has recently started a formal program to build even better, code-plus homes that could stand up to local hazards and document the methods used during construction. The name of this new program is Habitat Strong. Simpson Strong-Tie is proud to be a major sponsor of the program.

Habitat Strong actually began as a pilot project funded by Travelers Insurance that built 20 disaster-resistant homes in Alabama, Mississippi, New York and Connecticut. The success of that project convinced Habitat of the importance of building stronger, more resilient homes in all parts of the country. Starting from those regional hurricane-inspired efforts, the Habitat Strong program is now being used by more than 48 affiliates throughout the country, as shown on this map.

Habitat for Humanity Habitat Strong affiliate map.

According to Habitat for Humanity, “The Habitat Strong program is designed to promote the building of homes that are more durable, resilient, and physically stronger. The need for stronger homes has become increasingly apparent, and through Habitat Strong’s fortified codes-plus building practices, we are able to strengthen homes’ building envelopes, which enable[s] them to better withstand natural disasters in every region of the country. This program was developed specifically for the Habitat model to be affordable and volunteer-friendly, while offering benefits to partner families that will last for years to come. Based on these principles, we believe that building homes Habitat Strong is the right thing to do!”

Habitat for Humanity has established a set of construction standards for Habitat Strong that are based on the Insurance Institute for Business & Home Safety® (IBHS) FORTIFIED Home™ program. The FORTIFIED program is a scientifically developed, systems-based incremental approach for creating stronger, safer homes. There are three levels of FORTIFIED Home™ designations: Bronze, Silver and Gold. Each level builds upon measures at the preceding level to increase the disaster resistance of the home. You can take a look at the FORTIFIED Home standards on the IBHS website at www.disastersafety.org.

There are now three separate sets of FORTIFIED Home™ standards: Hurricane, High Wind & Hail, and High Wind. In general, the three levels consist of the following:

Bronze:

  • Strengthen roof deck fastening by using 8d ring-shank nails in a closer-than-normal nailing pattern.
  • Apply a secondary water barrier to the roof deck so there will still be protection from water damage even if the roof covering is blown off.
  • Install a roof covering that is rated for high winds and, if appropriate, hail forces.
  • Prune nearby trees to prevent damage to the home during a wind event.

Silver:

  • Complete all requirements for Bronze.
  • Brace gable ends over 4′ tall and ensure they are sheathed with a minimum thickness of wood structural panel.
  • Anchor wood frame chimneys to the roof structure.
  • Anchor attached structures, such as porches and carports, from the roof to the foundation.

Gold:

  • Complete all requirements for Silver.
  • Provide a continuous load path for wind forces from the roof to the foundation. In a normal 115-mph wind zone, the load path is to be designed for at least 140 mph.
  • Provide a garage door that is rated for high winds.

Habitat for Humanity is recommending to their affiliates that homes built in coastal areas be built to the IBHS Gold standard for hurricanes, and those built in inland areas be built at a minimum to the Bronze or Silver standards for high winds. The Habitat homes that meet the Bronze or Silver standards will be certified as Habitat Strong. Habitat homes that are built to the Gold standard will be certified as Habitat Strong+.

Simpson Strong-Tie is proud to be assisting Habitat for Humanity with Habitat Strong. In January, we hosted a training for Texas affiliates that was offered by Habitat and IBHS staff at our Houston training facility. We also donated connectors for a demonstration home at Michigan State University that we helped design.

If you would like more information on Habitat Strong, contact HabitatStrong@habitat.org. To learn how you can help Habitat for Humanity, visit www.habitat.org/getinv/volunteer.

Are you aware of any other programs for strengthening affordable housing? Let us know in the comments below.

 

 

 

Impact Community Resilience as a USRC Member and Certified Rater

The U.S. Resiliency Council (USRC) recently launched its Building Rating System for earthquake hazards. The Rating System assigns a score of from one to five stars for three building performance measures: Safety, Damage (repair cost) and Recovery (time to regain basic function).Continue Reading

What Factors Contribute To A “Resilient” Community?

The world has seen many increasingly catastrophic natural disasters in the past decade, including Hurricane Katrina (Category 3) striking New Orleans in 2005, 2010’s 7.0 magnitude Haiti and 8.8 magnitude Chili earthquakes, the 9.0 magnitude Japan earthquake along with the Christchurch earthquake (6.3 magnitude) in 2011, the tornado outbreak in 2011 which included an EF4 striking Tuscaloosa, AL and a multiple-vortex EF5 striking Joplin, MO. We also saw Category 2 Hurricane Sandy, the largest Atlantic hurricane on record in 2012 and the EF5 tornado striking Moore, Oklahoma in 2013.

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