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.