What wind and water can do to a building
High wind and water disasters have major implications for design. A Texas architect reflects on his experience responding to Hurricane Harvey, the damage he saw firsthand, and what architects can do to prepare themselves and their buildings for hurricanes and similar events.
Hurricane Harvey made landfall north of Port Aransas, Texas the night of Friday, August 25, 2017 as a Category 4 storm. With peak winds of 132 mph and storm surge levels of up to ten feet, it was clear to me that Harvey would damage a large swath of land and that its effects would reach far inland. The storm stalled over Texas for nearly four days before re-entering the Gulf of Mexico, traveling Northeast, and making landfall again in Louisiana. As Harvey lingered, torrential downpours fed by the Gulf of Mexico’s warm water dumped over 60 inches of rain from Houston to the Louisiana border.
Distressing news reports of Harvey’s impacts began filtering in, showing massive coastal damage and inland flooding. I wanted to help, but I knew untrained or unorganized volunteers can unintentionally cause additional work for first responders and even slow down recovery efforts. My answer came in an email from AIA asking for licensed architects to conduct building safety assessments.
After attending a full day Safety Assessment Program evaluator training, I performed building safety assessments in Aransas County, Port Aransas, and surrounding communities. I met with local judges, mayors, and city staff to coordinate more than three dozen volunteers. Together, we evaluated over 12,000 structures in just three days. From these exterior building assessments, I came away from the experience with more than a few observed design lessons.
Understanding wind and water damage
Wind damage seen after a hurricane is similar to that caused by a tornado and water damage is akin to the impacts of a small tsunami or flash flood. High winds can create varying degrees of damage within a community—ranging from the loss of some siding, windows, or gutters, to the complete collapse of a structure. After Harvey, homes that still looked brand new stood alongside foundations that were wiped clean.
As the storm came ashore its winds switched direction, lifting roof shingles, damaging decking, and bringing suction forces that tore stone and brick veneers from facades. Such impacts often stem from inadequate detailing such as a lack of hurricane clips and other connectors, poorly attached shingles, inadequate bracing of first floor pier-and-beam systems, and poorly installed masonry anchors.
Water can be just as vicious as wind. In the structures we assessed, roof leaks led to ceiling collapses, and interior flooding created a breeding ground for mold. As waves surged onto the shore, they tore away sections of structures that had not been elevated, scoured foundations and streets, and washed away entire buildings. Breakaway walls under elevated structures protected the structures they were a part of but also yielded debris that impacted neighboring unelevated homes. We noticed that water damage can be exacerbated by a lack of secondary water barrier like taped sheathing joints or poorly-installed chimney caps and chases. When those elements aren’t intact, water can pour into a structure very easily.
Reducing potential damage during new construction and retrofits
Our assessments yielded many lessons for design and construction choices. When starting a new project in an at-risk zone, careful site selection, elevation, and a continuous load path are just a few strategies to limit the dangers of wind and water. Ensure that structures are designed and built to meet or exceed the wind design criteria of newer model building codes. Investigate hazard mitigation best practices and Code-Plus programs, understanding that code-minimum construction cannot guarantee resilience.
During a redesign or retrofit in a hurricane-prone area, there are many things to consider. Seek to strengthen the connections and structural elements on decks and porches so they do not turn into debris that can cause harm or damage in a neighborhood. Locate outbuildings and other easily moved elements away from homes and correctly secure them to avoid creating additional wind and water borne debris. Whether you’re constructing a new building or updating an existing one, it’s critical to remind clients of the importance of landscape maintenance. Proper trimming of adjacent trees can reduce the risk of trees falling onto homes and businesses.
Lessons learned for an entire region
The cascading effects of wind and water damage from Harvey were innumerable for communities in the Gulf Coast. In counties where I worked, thousands of power poles and trees went down, a major cell phone tower site was flooded, and docks, roadways and utility facilities were damaged, cutting entire communities off from basic needs like water, food, sanitation, and electricity.
On a regional level, it’s important for architects to encourage community leaders to prioritize protection of critical infrastructure like power grids, sewage treatment, and means of transportation. The cost of taking these things in consideration up front is much less than the financial and emotional cost of a disaster like Harvey, now the second costliest natural disaster in US history. Hopefully, peace of mind and the desire to create a tenable structure for future generations may override cost considerations.
While I helped as much as I could after the storm, I soon became focused on exploring what I could do before the next storm hit. As an architect, the time to help reduce impact from a disaster is right now. As I see it, architects who can, have the responsibility to get trained as “second” responders to assist communities recover as soon as possible. Further, we need to talk to our clients about hazard risk and design to reduce potential damage—making our structures and our communities—more resilient to disasters like Harvey.
Shawn Gillen, AIA is Vice President and co-owner of DFD Architects, a former Texas HHSC Surveyor and Texas State Guardsman who specializes in long-term healthcare design and code compliance. He is also a member of the AIA Disaster Assistance Committee.
Rose Geier Grant, AIA, is a consulting architect with disaster response experience, specializing in hazard mitigation and risk communication. She is chair of the AIA Disaster Assistance Committee and a member of the AIA Blue Ribbon Panel on Codes.