Know Your Home: Foundation Basics

Beachside Foundation

Image via Alpha Structural

Clients often come to us with questions about their home’s foundation. It’s one of the biggest areas of concern for homeowners, buyers, and sellers–and with good reason. “A proper foundation does more than just hold a house above ground,” says This Old House. “It also keeps out moisture, insulates against the cold, and resists movement of the earth around it. Oh, and one more thing: It should last forever.”

We always advise our clients to conduct a foundation inspection before purchasing a home, and to make sure that they are aware of their foundation’s condition before selling. To help you understand the basics, we’ve answered some of your most frequent questions below.

1) What are the different kinds of foundation? 

There are several variations, but the three most common are slabraised, and basement.

slab foundation is exactly what it sounds like: a thick concrete slab that is poured directly onto the ground at the construction site. Slab foundations are usually reinforced with steel bars and wire mesh. They tend to work better in warm climates (like LA), because cold weather can crack them.

raised foundation uses piers and beams to create a small crawlspace underneath the house, typically around 18 inches. This not only allows access to the underside of the house, but also creates a separation between the earth and the home, which can protect against moisture intrusion in damp areas.

Basement foundations have high walls and a slab at the base. The walls can be room height or partial height, and are usually reinforced and waterproofed. Basement foundations can be used for storage, or even as an additional room in the house.

2) What are the signs of foundation trouble? 

According to Alpha Structural (one of our frequent foundation inspectors), “Cracks in foundations, sticking doors or windows, gaps in window door frames, cracks in interior walls and ceilings, and uneven floors” can be signs of trouble of some cases. Best to discuss with a qualified foundation specialist to determine if the issue is serious or not.

Foundation Issues

Image via Alpha Structural

3) How do I know if I need earthquake retrofitting?  

California is known for its earthquakes, but many homes built before the mid-1940s were constructed without bolts to anchor the frame of the home to the foundation. After the Northridge earthquake in 1994, the city of Los Angeles revised its building codes to provide further protection in the event of a quake. If your home was built before or during either of these time periods, you may want to consider a seismic retrofit to improve its resistance to damage.

According to contractor Paul McGrath (another one of our frequent foundation inspectors), the retrofit procedure usually involves “bolting the lumber house frame to its concrete foundation, bracing the below-floor framed cripple walls, and connecting framing lumber with framing anchors.”

In some homes, upper stories are constructed over a garage, which can cause something known as a ‘soft story’ condition. “Bracing the seismically weak wide door opening often requires an engineered structural frame,” says McGrath.  Fortunately, most homes can be seismically retrofitted for a modest cost.

In addition to making your home safer, retrofitting may also qualify you for reduced premiums on your homeowner’s insurance. Check with your provider.

Hillside Foundation

Image via Alpha Structural

4) What’s involved in a standard foundation inspection? 

When you book a foundation inspection, your trained assessor will begin by inspecting the crawlspace of the home for any problems with the foundation. Next, they will walk through the interior of the home to look for any unevenness of flooring, cracking or other telltale signs of trouble. Then, they will look at the exterior of the home for any potential drainage issues that could cause erosion, as well as any further signs of trouble.

The inspector will then share their findings with you, and provide you with options for addressing any issues. Their goal (and ours) is to ensure that your home will remain safe, solid, and secure for many years to come.

Note: We are not certified foundation inspectors. The information contained in this post should not take the place of a home inspection. If you have questions or concerns about your home’s foundation, please consult an expert. We would be happy to provide you with a list of trusted vendors.

Canyonhaus has more than 30 years of combined experience in the Los Angeles real estate market. We’ve seen it all! If you’re thinking of making a move, contact us today. We are always happy to hear from you.