Construction

Coastal living creates need for resilient design

WEATHER-RESISTANT: This "fortified" house located on the water in North Kingstown has structural improvements that make it resistant to wind, rain, sea-level rise, and other environmental factors. The vertical concrete foundation beams go down into the ground 20 feet and encase steel rods.
WEATHER-RESISTANT: This "fortified" house located on the water in North Kingstown has structural improvements that make it resistant to wind, rain, sea-level rise, and other environmental factors. The vertical concrete foundation beams go down into the ground 20 feet and encase steel rods. PBN PHOTO/ MICHAEL SALERNO
By Mary MacDonald | MacDonald@PBN.com
3/16/17

THE reality of oceanfront living in Rhode Island is a mixture of rain, wind, ice, snow and storm surge, depending on the season.

This, and the fact that so many properties are now impacted by potential flooding, has created a subset of construction and designers who specialize in resilient homes and buildings.

The idea behind resilient design is to engineer a building, or addition, that is able to withstand a changing, and challenging, environment.

"A lot of people have a misconception about green building, or sustainable building practices," said David Caldwell, an owner of Caldwell & Johnson Inc., which specializes in fortified structures that are insured at rates that reflect their durability.

"One of the most important things is to build a durable building," Caldwell said.

More than 13,000 properties in Rhode Island are in a Federal Emergency Management Agency flood zone, according to the most recent maps, which were updated after Hurricane Sandy in 2012 and the severe flooding of interior rivers in 2010.

That has triggered a set of requirements for new construction and additions. For additions, if the project is worth more than half the value of the home, it has to comply with the flood zone standards, which means elevation of the first floor above the flood level.

In the village of Wickford, in North Kingstown, Caldwell & Johnson Inc. is building a four-bedroom home that will, on completion, be certified as fortified. The fortified program is an effort of the Insurance Institute of Business and Home Safety, which offers engineering and building standards designed to make structures more resilient to natural hazards, including hurricanes, flooding and wind storms.

The home under construction in Wickford, fronting a saltmarsh and Narragansett Bay, is expected to be completed later this year.

The Wickford house is in a velocity flood zone, where the strongest forces would come in a hurricane. The design, by architect Gail Hallock, includes 17 steel-reinforced support columns that will raise the first floor of the house up 16 feet, above the floodwaters. The columns are secured to the house and to bedrock 20 feet below the ground.

Caldwell has no doubt the house will withstand a hurricane.

"No question about it. If this house is not here, Wickford is not here," said Caldwell, who grew up in the area. His grandfather built a small seaside cottage near the house site that was wiped out in the Hurricane of 1938. After that, many longtime residents moved inland.

Now, attracted by spectacular views and waterfront access, many Rhode Islanders once again want to be near the water. In addition to the secured foundation, the roof will have about double the number of nails and a binder covering the seams below the shingles.

This is an often-overlooked aspect of resilient design. "Most people get more damage in a hurricane from the roof than from flooding. The water penetrates," Caldwell said. "The older houses have plywood [beneath the shingles]. You'll often see gaps in the plywood."

The house fortification process will add 10-15 percent to the total cost, he estimated. The foundation on the Wickford house is about $200,000, including excavation. But that homeowner will recoup the expense of fortification in three to five years, Caldwell estimated, because they will not have to obtain flood insurance for a V-zone, the costliest version.

"Essentially what you've done is you've taken the house out of the flood zone by lifting it," he said.

As it now appears, the house under construction is clearly elevated. But on completion, its support piers will be hidden by the completed landscape and a porch that will wrap around the house and soften its verticality, said Hallock.

"What you are going to see from the street is a house set into a hill. The grade was peeled away in order to put the beams at one level. There will be a lower garage entry, like a lot of people have. There will be a little hill, and a little wall, and a wraparound porch," she said.

Two-thirds of her business is for clients who have property in Rhode Island flood zones, including alongside marshes and rivers.

Her work is divided into two segments, meshing the realities of the sites and standards with a design that will be functional and beautiful. "For me, it's combining the engineering with beauty. I don't want the house to be on stilts. I don't like that look, unless I have absolute reason to do that," she said.

The Wickford house represented a significant challenge. Its support columns will be 16 feet high. To make that work visually, she positioned the house on its site in a more aesthetically pleasing way. "I pulled the house into the hill. I cut the verticality with the porch. It took me a bit of sketching," she said. •