Plans for the 400-sq.-ft. addition looked straightforward: a new dining room, a pantry, and a full bath stretched out along an existing wall of the house. Ordinarily, the wood-frame structure might have gotten concrete footings and stem walls if not a full foundation, but designer Michael Maines decided to build the structure on helical piles instead.
“She doesn’t care about additional basement space; she wants to keep costs as low as practical; and she doesn’t want to create unnecessary carbon emissions or other negative environmental impacts,” Maines said in an email about the project for his mother-in-law. “Additionally, access is tight and the septic system drain runs under the addition…. So piers just seemed to make sense.”
The 10 hydraulically driven steel piles will cost the homeowner $3000. Maines, a builder and designer as well as a contributing editor at Fine Homebuilding magazine and a GBA Expert Member, didn’t price out the concrete work, but he guesses it would have cost twice as much as the piles. Then there’s the excavation and related issues he’s also avoiding.
Maines’s decision to opt out of concrete in favor of helical piles neatly sums up their appeal on both economic and environmental grounds: They are faster, less disruptive to the building site, and often cheaper—and with none of the carbon baggage that comes with concrete.
Those advantages are helping to propel the industry into a new era, 182 years after the first helical piles (then called screw piles) were used to support a lighthouse on the coast of England. While builders like Maines may choose them for new construction, they are more often used in residential work for foundation repairs and reinforcement. On commercial and industrial projects, helical anchors and helical piles have a variety of uses.