Building to Last: Designing Under Extreme Conditions
Building and remodeling on the shore requires storm-savvy design and time-tested techniques.
Earthquakes, erosion, and howling winds go hand-in-hand withliving near the ocean. Fortunately, when homeowners opt fortraditional building methods instead of up-and-coming pre-fabsystems, techniques exist for coping with this wide weatherspectrum. The chief tactic is prudence. "Never fool with MotherNature," says architect Louis DesRosiers, who designs homes on theGreat Lakes. "You'll lose every time."
In any coastal area, a foundation engineered to anticipatebrutal storms is the first line of defense. "What we're doing now,"says Southern California architect Lewin Wertheimer, "is settingthe whole house on concrete caissons that go to bedrock. All thesand could be washed away, and the house would stand. It's likefreeway construction."
In Lewin's Malibu houses, he says, "You're probably looking at aquarter of the cost of the entire project going into thestabilization of the site."
The most common problem for homeowners, says veteran Nantucketengineer John Shugrue, "is being in too much of a hurry and notdoing the research. Most people don't want the foundation part ofthe job to take too long. They can't see where the money is going,so they think they're paying for nothing. In reality," he explains,"the foundation is the most important part of the job, because itholds everything else up."
When the foundation is in place, New York architect John R. Kirkargues for "threaded rods that go all the way from foundation upthrough the framing to the rafters," providing the bones of thestructure. "Plus shear walls," he says, explaining that thesereinforced interior walls will resist twisting when the house ishit by high winds. Architects also reinforce weak points, such aslarge windows, with steel tubing.
In the Pacific Northwest, architects use large roof overhangs ondecks and porches to protect siding and windows from the region'snotorious rain. Without careful planning, overhangs can becomevirtual sails, exposed to uplift that can pry a roof off its walls.Washington architect Peter Brachvogel guards against uplift byusing threaded steel cables and extending the roofline withbeefed-up rafters to support the eaves. "And we tie the buildingtogether with all kinds of hardware," says Peter.
This hardware includes clips and connectors refined throughyears of storm experience. Connectors fortify vulnerable pointsthat link floors, walls, rafters, and roofs. And because they'realmost impossible to retrofit, they must be installed correctlyduring construction.
Tim Reinhold, vice president of engineering for the insuranceindustry's Institute for Business and Home Safety, took a survey ofFlorida's recently affected areas. He says little things, such asproperly installed connectors, influenced the survival rate ofhomes. "In Charley, where we had gusts of 140 to 150 mph," saysTim, "we didn't see roofs flying off houses."
Other easy choices, including the use of ring-shanked nails inclose patterns to secure plywood sheathing on roofs, made a bigdifference in the region. So, too, did tight soffit systemsdesigned to block rain penetration, yet allow for atticventilation.
Tim noticed other details that protect against hurricane winds.Trimmed trees and properly tended landscaping fared well. Securelyanchored fence sections were less likely to become airbornemissiles. But, Tim warns, in wind gusts of 100 mph and higher, ifanything can go wrong, it will. "Murphy's Law is alive and well inthese conditions," he says.