Designing Your Home for Extreme Weather

By Boyce Thompson

Here are considerations for building a home that withstands extreme weather.

Fires burning out of control in the mountains. Torrential rains hammering the coasts. Tornadoes ripping up the Plains. Severe weather appears to be growing more common. What does this mean for the design of your next home?  

That depends, of course, on where you plan to build. Some local codes theoretically have you covered. A new home built in Florida, for instance, must comply with the state’s hurricane code, which requires windows that can withstand flying debris and roofs securely tied to the frame. If you build a home in California’s fire zone, its eaves must resist the spread of flames. If you build in a flood zone along the Gulf Coast, you may need to raise the home’s foundation above the 100-year flood zone.  

Elsewhere in the country building codes may not provide much protection against increasingly common extreme-weather events. That’s because local codes focus on basic safety (making sure the building doesn’t collapse) and protecting people inside the home (so that you have a means of egress). They rarely go the extra mile to protect the structure from damage, or safeguard other property in the home. Another big problem: spotty enforcement of building codes, a big reason why there was so much damage after Hurricane Andrew in Florida.  


Dan Sater, who designs most of his homes to Florida’s hurricane standard, says many details designed for high-risk areas can be easily adapted to any home plan. “We incorporate things like impact-resistant windows and shuttered patios for protection in most of our plans,” he says. He recommends building closed attics with spray foam insulation; they will do a better job staying in place during high winds. He points out that metal roofs perform better than shingled or tiled roofs in hurricanes. “And hip roofs obviously do a better job than gables resisting high winds.” His own home, plan 930-19 (above), features a hipped roofline.


Designer Bruce Tolar (who created plan 536-7, above) learned his lesson about hurricane resistance the hard way: his Mississippi home was damaged by Katrina even though it was built above the flood plain. 

The structure survived intact but three feet of water in the kitchen took its toll on interior finishes. Based on that experience, he recommends using real wood cabinetry, which will fare better if it gets wet. He suggests not using wall-to-wall carpeting on the lower levels. And he recommends considering the many mold- and mildew-resistant building materials on the market today. Most wallboard companies, for instance, market mold-resistant varieties that only cost about 10 percent more than standard drywall. You can also buy framing and insulation treated to resist mold.

After the storm, Tolar designed some homes as part of a series of Katrina cottages that can resist 140-mph winds and high water. Most of the plans, designed as an alternative to “FEMA trailers,” require wood-piers or concrete-post foundations. In some cases, local codes may require drilling into bedroom to support the posts. The quaint homes range from 400 to 1,400 square feet. 

If you are building along the coast, there are many other things to consider. One good piece of advice from the Fortified Home Foundationinstall electrical components at least a foot above the base flood elevation for your area. You may also want to consider raising HVAC equipment to an upper floor or building a flood-proof wall around it. Another good precaution: install sewer back flow values that prevent sewage from backing up and returning to the same house. Many of the homes in the Low Country collection at Houseplans.com feature pier foundations.  


Fire, of course, is a different story. California and Colorado, which publish standards for high-risk areas, recommend that you create a radius around your house free of flammable materials. California requires tempered glass on glazed doors and windows, non-vented eaves to prevent fire embers from entering, fire-rated drywall under finished wood porches and eaves, and thick wood members (2 inches or more) on covered porches and eaves.  

The California standards are basically designed “to slow the flame spread and buy more time,” says Nick Lee, whose does business out of Petaluma, California. He watched in amazement as the recent wildfires engulfed whole communities. “With the intensity of the fires that we are having I’m not so sure what would be able to withstand the fire except for masonry structure.” Designing separate structures could help fire from spreading. “We design houses with detached garage and detached bedroom wings from the main portion of the house.” Even a covered breezeway could help, as in plan 888-17 (above).


Fire-resistant wallboard, plywood, and decking can also protect you home from fire. “Sprinkler systems are pretty inexpensive when included in the original build,” says Nick Foley, publisher for Don Gardner Publishing (see the collection on Houseplans). Foley points out that many house plans could be adapted to include more fire-resistant materials. For example, plan 929-8 was originally designed with traditional siding but was built with fiber cement siding and a metal roof (above, photo courtesy of Donald A. Gardner Architects). See more plans with metal roofs here.

Careful attention to construction details can also help protect your new home from fire, wind, and water. Make sure shingles and soffits are firmly attached; that gaps in the exterior envelope are caulked to prevent wind-blow water from entering. That may not protect your home from a catastrophic weather event. But every little bit surely helps. 

Thu Nov 09 00:00:00 PST 2017