Residential

How to Design a Coastal Home to Survive Hurricanes

Building Destroyed by Hurricane Harvey


When starting to design a home in a coastal windstorm location, a holistic design approach must be used. There is no single method­ol­o­gy or building product that will create a resilient structure capable of with­stand­ing the high winds, heavy rains, and potential storm surge of a hurricane. There are three distinct areas that need to be evaluated. First is choosing the right team of building pro­fes­sion­als that have the expertise and knowledge to design and build in a windstorm area. Second is the specific design criteria that will con­tribute to the building’s dura­bil­i­ty. Lastly are the materials that should be selected for their per­for­mance in windstorm conditions.

Building Professionals

Choosing an architect or designer who has expe­ri­ence with code require­ments and building practices in a windstorm area is critical. These are the people who will be able to help guide the project’s design to meet the needs of the owner and the relevant building codes. A windstorm engineer is not only required* to meet code and be insurable, but also ensures that the building will be con­struct­ed to withstand the forces imparted on a home during a hurricane or tropical storm. Picking an expe­ri­enced coastal home­builder is the last part of the team of building pro­fes­sion­als. A knowl­edge­able builder will be able to price the home correctly and build it to standards set forth by code, the designer, and the engineer. 

Design Criteria

There are multiple criteria that should be reviewed and imple­ment­ed when designing a home in a coastal area, including:

  1. Site selection: Utilizing wind breaks from other struc­tures and trees can lessen the wind forces on the building during storms while being mindful of the potential for trees and other materials to become airborne and cause damage to the structure.
  2. Finished floor elevation: Designing the house on piles or sig­nif­i­cant­ly raising the elevation of the site can make the dif­fer­ence between storm surge flooding the structure or not.
  3. Keeping walls shorter: Design the home to have shorter overall heights of walls on single stories and less floor-to-floor heights on multi-storied buildings. This will lessen the overall wind pressure on the structure.
  4. Lower roof pitches: A low profile roof will have less wind pressure imparted to the roof and con­se­quent­ly to the rest of the structure.
  5. Avoiding large open roof areas: Try to avoid extended eaves and deep roofed porches, as the high winds put upload pressure on these areas which can cause sig­nif­i­cant damage to the roof.
  6. No ridge vents: While there are some benefits asso­ci­at­ed with having ridge vents, they become open water drains into homes when hor­i­zon­tal and wind-driven rain is pushed up a roof. 

Building Materials

There are specific building materials that should be used when building in coastal windstorm areas. Each of these cat­e­gories has multiple choices of materials that have been tested to withstand the forces of windstorm events.

Roof

The design of the roof is critical to resisting the forces of hur­ri­canes, but the selection of roofing materials is equally important. A fully-adhered ice and water shield should be applied to the roof sheathing, replacing con­ven­tion­al mechan­i­cal­ly fastened felt paper. If the roofing material becomes com­pro­mised, this more resilient barrier can keep rain from entering the structure. There are many different roof finishes, but close attention should be paid to the details. For com­po­si­tion shingles, it is important to follow instal­la­tion best practices in windstorm areas, and to use materials with the proper wind clas­si­fi­ca­tion. If a metal roof is chosen, the end cap detail needs extra con­sid­er­a­tion. If a metal roof is damaged by wind, often times, entire sections will be peeled off the roof.

Wall assembly

The load bearing wall assembly is an essential part of the design. Choosing the right materials for the walls should be one of the first decisions made when designing a house on the coast. Robust, resilient concrete walls are the best per­form­ing system in high wind events. Not only do the walls withstand the wind forces, but they also defend the structure against wind-borne debris. The Bautex Wall System is a proven insulated concrete wall system designed for coastal struc­tures. Tested to FEMA 320361 and ICC 500 require­ments for windstorm, Bautex walls are easily installed and are highly energy efficient. With the Bautex wall there is no wood or exposed steel that are sus­cep­ti­ble to rot or rust, and, ulti­mate­ly, to struc­tur­al failure during a windstorm event after years of exposure to salty and humid marine air.

Windows and Doors

Spec­i­fy­ing impact resistant and tested windows and doors is a must-do. If a house is built with the most durable walls and roof but has weak windows or doors, the building can become com­pro­mised in a hurricane or tropical storm with high winds and flying debris. Hurricane windows are worth the invest­ment when compared to the costly water damage that can occur during these types of storms.

Finishes

Unless connected to a more sub­stan­tial concrete wall system, cavity wall finishes such as brick, stone, tra­di­tion­al stucco on metal lath, or rain screens should be avoided when building a house on the coast. Wind pressures can get behind these types of cladding materials and cause them to be pulled off the building. On wood sheathed buildings, this leaves the shear rein­forc­ing system (the sheathing) exposed directly to the windstorm forces which can lead to complete struc­tur­al failure of the building. Choose direct applied and tested finishes that perform better in high wind storms.

There is no exclusive solution to designing a resilient costal home. The design must be looked at holis­ti­cal­ly. The right design pro­fes­sion­als are a great first step, but ensuring critical design prin­ci­ples and choosing the best materials are also vitally important. Only when all of these items are done in con­junc­tion can a durable and safe home be designed and built in high windstorm areas.

For more infor­ma­tion about building a resilient home in a coastal area, go to bau​texsys​tems​.com or send us an email.

*In order to be eligible for coverage through the Texas Windstorm Insurance Asso­ci­a­tion (TWIA), Texas Insurance Code Chapter 2210 states that any building con­struct­ed, altered, remodeled, enlarged, repaired, or added to on or after January 1, 1988 must have a Cer­tifi­cate of Com­pli­ance (WPI‑8 or WPI-8‑C) to certify that the structure meets the windstorm building code require­ments. Without a Cer­tifi­cate of Com­pli­ance, TWIA lacks evidence that the structure conforms to the applic­a­ble building code, and the structure may be con­sid­ered unin­sur­able and inel­i­gi­ble for coverage with TWIA.