By Lynne Hendricks
Staff Writer
November 06, 2009 03:56 am AMESBURY — Rather than spend another rainy season lamenting their thrice-flooded basement, two fed-up homeowners living along the Merrimack River floodplain decided to take drastic measures to secure their home against the seasonally rising river. While they can't stop the river from taking its natural course to the Atlantic and swelling each spring with rain and snowmelt, homeowners John and Jane Stevenson of 439 Main St. decided to try an old fashioned, albeit expensive, engineering project to fight the flooding. The remedy involves hoisting their 2,036-square-foot home up on steel piers to build a new flood-friendly ground floor beneath it, which has made the house something of a curiosity to passersby. It's an old construction method Town Engineer Pete Manor said can be expensive, but effective. "With their original house, their basement was constantly getting wet during flooding occurrences, so what they're trying to do is just raise it up so they have more flood storage under the house," said Manor said. It's a unique means of adding onto a structure, and one that requires careful attention to ensure the structure's integrity remains intact through the job, Manor said. How is it done? "Very carefully," said Manor, through the use of hydraulic jacks that are placed under the house and an incremental lifting that keeps each side moving upward in equal measure. "You lift it up by jacking it up at certain points under the house so the house goes up evenly — you do it in increments. It's an engineering construction process that would have been used in the olden times." According to plans Manor reviewed and approved when the Stevensons first proposed the project, the completed house drawings, done by Healy Construction of Amesbury, call for piers on the back side of the house and a retaining wall on the front, with open space in between to provide flood storage space and decrease the chances of mold taking root. "They're raising the house up to alleviate a problem and to provide a better environment," Manor said. "They're putting in a substantial cost to mitigate potential problems in the future. I know its not inexpensive." Building Inspector Dennis Nadeau said that the Stevensons' house was built in 1985 before flood maps enacted regulations on raising the first floor to a required flood elevation. But like others built before the regulations were put in place in 1992, the Stevensons are subject to the new codes because they're proposing repairs that cost in excess of 50 percent of the home's value. The Stevensons weren't available for comment. The cost of the work wasn't available; the house itself is assessed at $290,000. "Any house that is along the flood plain that does repairs worth 50 percent of the home's value would be required to lift the house so the first floor reaches flood elevation," Nadeau said. "The guy has been flooded two or three times in the last few years real bad. Once he decided to do the work, then the Massachusetts building code requires him to get the house up out of the flood plain." Nadeau has been working with the Stevensons at every stage of their project, which has also passed through the Conservation Commission, the Town Engineer and the full Planning Board. Having passed out of the applicable review bodies, the project is moving swiftly toward completion, Nadeau said. "The concrete wall is already built in the front," Nadeau said. "They're backfilling some of it today." Once the new foundation is built up around the house, the temporary piers and steel beams will be removed, and the house will be lowered back on the new foundation, Nadeau said. "They're putting a full foundation in the front of the house; the rear of the house will be on block piers, and they'll have knock-out walls," Nadeau said. It's a tricky feat that he's seen accomplished for some of the older homes on Plum Island and Salisbury Beach, which are also prone to seasonal flooding. Though the hydraulics lift is a great way to provide a solution for flooding, the cost might not make it the right choice for homeowners who wish to provide some extra square footage to their home. "It's a very expensive way," Nadeau said. "It can be an awfully expensive addition."
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