They say a house is only as strong as its foundation. A bad roof or shoddy plumbing can set your building back a lot of money, of course—but a foundation in disrepair can put the entire building structure at risk. It can also cost tens of thousands of dollars. Since it's literally underground, it's easy to ignore, and can be difficult to inspect, but the health of a building's foundation is crucial. A little bit of education from the professionals can go a long way to raising anyone's awareness on the importance of a good building's foundation.
Every region has its own architectural quirks, but New Jersey's housing stock is pretty consistent when it comes to foundations. “The most common is a strip-footing foundation, which is a concrete footing that's required to be down at least to the frost line,” says William Pyznar, P.E., vice president and structural engineer at Falcon Engineering in Bridgewater. “You're going to see a similar type of foundation in most buildings, regardless of the age. There will just be some different materials, whether it be concrete or stone,” he says.
You might have heard the term “strip-footing” foundation before, but didn't go to engineering school. It’s usually comprised of “masonry blocks or poured concrete foundation walls sitting on top of poured concrete strip footing. Underneath a foundation wall—sometimes it's reinforced, sometimes it's not reinforced—what they do is they'll dig a trench at the base of the wall, there will be reinforcing steel in there. It's called a strip footing because it runs continuously underneath the wall to support it,” says Mark Yanchuk, P.E., AIA, LEED AP, vice president and structural engineer at Kipcon, Inc. in North Brunswick.
The types of foundations change when you get close to the Jersey Shore. “If you go into coastal areas where the soil doesn't have the proper capacity, you're going to see pile-type foundations. Those are wooden piles that are driven down to a depth that either the friction can hold the pile in place, or it goes down to the bedrock,” says Pyznar. “The other thing that you might have in coastal areas is what's called a mat foundation, and that's where a large concrete slab is poured to distribute the load over a large area of soil,” he says. Pyznar says the state has changed elevation requirements for the first floor because of Superstorm Sandy. But the foundation methods won't change.
Buildings on the shore face more challenges with their foundations. Salt water is very corrosive, and can damage the concrete over time. “In an area where you have piles, if you have pile caps that are exposed to the ocean, you might have some type of erosion or deterioration as a result of the salt, and storm waters over many years,” says Pyznar.