Where do you put the house while building a higher foundation?
Centuolo and her husband, Gus Nisivoccia, are lucky, if you can call someone who's had to gut a flood-damaged home lucky, because their yard is big enough that the house could be slid out of the way on steel rollers in order to demolish the old foundation. This week, Amon Construction workers plan to drive stout, 25-foot-long timbers into the soil - 15 feet below ground, 10 above - and the house will be placed on top.
For properties with smaller yards, owner Bob Amon said, he has to break the job down into pieces, moving the house several times because the building's entire footprint cannot be exposed all at once. If necessary, he will temporarily move part of the house so it hangs over the water.
Either way, you need vertical space to drive the long timber pilings into the ground.
On the Shore, such pilings are typically used in areas where the Federal Emergency Management Agency deems that there is potential for high-energy waves - so-called V or velocity zones. The timbers allow space for the water to slosh around in between.
In higher and drier areas, owners are allowed to build a "closed" foundation out of, say, cinder blocks. So elevating the structure is a bit easier. Rather than move it sideways, workers can lift the house little by little, raising the foundation one layer at a time with cinder blocks.
V zones were greatly expanded in FEMA's new preliminary maps, forcing many owners to make a difficult choice.
The price of inaction
The price tag for elevating Centuolo's house is more than $45,000, including the disconnection of electrical service and plumbing, removal of the old slab foundation, and installation of the timber piles. But if they did not have the work done, the couple anticipated their flood insurance would increase by $10,000 a year.
Underneath the house, each of the air bags was surrounded by "cribs" made of short wooden beams. The bags were inflated multiple times, each time lifting the house about six inches. In between each inflation, workers added another layer to the wooden cribs to secure their progress.
Hydraulic jacks are another option for lifting a house, but Amon prefers air bags because while they are slower, he said they are safer.
Farther down the shore in Brigantine, 10 owners have elevated their houses already, while an additional 100 have started the paperwork to do so, said city engineer Ed Stinson. An additional 650 have expressed interest in seeking FEMA assistance for a home elevation.
In one case, an owner decided the cost and hassle of raising the house was not worth it, and opted instead for demolition and eventual rebuilding, Stinson said.
As elsewhere, the issue of small lot sizes is posing problems in Brigantine. Moving a house into the street is not permitted.
"It's logistically a nightmare," Stinson said.
Another option for tight spaces is to use helical piles - steel rods that are fitted with spiral-shaped blades so they can be screwed into the ground as supports for a foundation.
'A little propeller'
The piles are only 6 feet long, so unlike with Amon's 25-foot timbers, not much clearance is required to twist them into the earth with Bobcat-style equipment. Once one rod is all the way in the ground, the contractor can attach another one on top and then twist again until there is 12 feet of steel underground.
Still more rods are added - 18 feet, 24, 30, and so on until reaching a certain level of resistance, and then the contractor moves a few feet to one side and starts all over.
Once the workers have installed a whole row of the rods, they are "tied together" on top with a concrete beam, which then serves as a foundation for concrete blocks or whatever material is used to elevate the house.
Philadelphia architect Charles Capaldi used these helical piles with his family home in downtown Ocean City, where there was scant room to maneuver. Workers screwed the rods more than 40 feet into the ground.
"It's almost like a little propeller," he said.
The depth to which piles must be driven depends on the soil, said Beena Sukumaran, chairwoman of Rowan University's civil and environmental engineering department. She said at the Shore, there is often loose soil on top and a layer of mud beneath that before you reach hard-packed sand, which provides the necessary friction to withstand the heavy load of a house. Some force is borne by the bottom of the piles as well.
For houses near the beach, another challenge in raising a house is that the front may rest on sandy soil while the rear is on more solid ground, said structural engineer Harris Gross, a home inspector in New Jersey and Pennsylvania.
With all these issues, he said, skilled labor is essential.
"There are not many companies out there that do this," Gross said. "You've really got to know what you're doing."
Watch a video of workers elevating a house at the Shore at www.philly.com/raise
Contact Tom Avril
at 215-854-2430 or firstname.lastname@example.org.