A home addition has a new basement foundation with a durable, heavy-duty plastic basement … [+]
Homebuyers are most often convinced to buy a house because it has the square footage they require, or it has curb appeal, or it is in the right school district. They pay attention to important elements like the age of the kitchen appliances, how dry the cellar stays during storms, whether the electrical system is up to code and the amount of storage and natural light.
But few think of one of the most important parts of any house, which is the foundation. Literally the underpinning of any building, the foundation can support a home with equanimity for generations, or it can be the source of damaging instability.
“It’s like a snowshoe,” says Tim Tracy, National Field Inspector Trainer for Groundworks, a foundation services company specializing in water management solutions and preventative work. “The foundation spreads out and bears the weight of the house the way snowshoes bear your weight and allow you to walk where you would otherwise sink into the snow.”
There are several kinds of these snowshoes for houses, including full basement foundations, which begin with a hole of at least eight feet deep to accommodate an underground living space whose floor space matches most or all of the home’s ground level. They are most often used in cold climates like the Midwest, Mid-Atlantic and Northeast regions, because the foundation must be placed below the frost line to prevent the home from shifting during freeze and thaw cycles.
A slab foundation, sometimes called a monolithic or monoslab foundation, is a flat concrete slab that rests on the ground and is poured in one single piece. Slab foundations are less expensive and quicker to construct. One downside is that sewer and drainage pipes have to be put in place before the concrete is poured and, in case of a sewage or plumbing problem, the slab has to be cut into to access the pipes. Slab foundations are not suitable in cold climates because, as the ground freezes and thaws, cracks can form in the concrete and it can shift.
In coastal areas, the best way to anchor a home above soil that’s constantly shifting, flooding or eroding is to build a pier and beam foundation. They work the same way an ocean pier does by fixing long pillars—often over 15 yards long to reach solid ground—into the deepest layers of stone and soil. Doing this requires the services of a structural engineer, and driving concrete piers involves heavy equipment, so this kind of foundation brings with it added time and expense.
“Foundations fail because of the ground they are put on,” Tracy says. “There is poor compaction, shrinking, or swelling – all nature-driven.”
He points out that many American houses are built on former farmland, which is often unstable. “Hills have been flattened, wet areas filled in; there are a lot of regional aspects to soil.”
When the soil under a foundation is unstable, the foundation develops cracks and the house settles. The whole house can settle and sink at the same time, or settling can be front to back or side to side. Or, a corner of the foundation cracks and affects the stability on one side of the house.
“The first symptoms are often sticking windows or doors that don’t open or close any more,” Tracy says. “If your foundation is brick or blocks, you might see a step crack.”
He recommends that homeowners experiencing settling call in a professional at the first sign.
“They can determine what is causing it, and can stop any further movement,” he says. “A steel pier can straighten out a crooked foundation and, as much as the structure allows it, can put things back in plumb.”
It may not be as much fun as looking at the garden or envisioning yourself cooking in a glamorous kitchen, but when house-hunting, take a little time to study the foundation. It holds up the whole house.
