If you live in an area in California that is at risk of earthquakes or other seismic activity, then it is important to make sure that your home is built to withstand such potential threats. A structural home inspection or evaluation can assist in determining whether your home meets Building Code requirements criteria for seismic bracing.
As a full-service engineering and land development company based in Santa Rosa, California, our team at Hogan Land Services works extensively with clients whose homes are situated in seismic hot spots. Here are seven of the questions that we receive most frequently from customers inquiring about our structural home inspection and evaluation services
Is my house safe?
There are two categories of seismic effects on a home; cosmetic and catastrophic . It’s important for California homeowners to understand the current code provisions for seismic design is NOT intended to prevent cosmetic failures. The seismic design principles incorporated into current building codes are specifically designed to prevent catastrophic failures of the structure. Cosmetic failures include cracking of drywall and finish work, cracks in concrete and masonry elements, and sticking of doors and windows. These types of seismic effects are expected even for designs under the current building code. Building Code requirements for seismic bracing has been around for about 40 years and is an evolving science. Residential requirements for seismic bracing is updated in the Code every 3 years. Most homes constructed after 1985 are likely to incorporate shearwalls or braced frames to resist lateral loads due to earthquakes. If you own an older home, you should consider checking your seismic zone, to see if your home is located in a particularly at-risk area.
Do I need a seismic retrofit?
Ultimately, only a professional can answer this question. If your home was built before 1985 and has never received a seismic retrofit, then there is a good chance that it needs one—particularly if you live in an at-risk seismic zone. You should schedule a structural inspection and evaluation to determine whether a seismic retrofit is required.
Why is my drywall cracking?
Foremost, it’s important to recognize that earthquakes and other seismic activity are not the only causes of drywall cracks. On the contrary, everything from soil characteristics, to moisture and foundation settling (the downward movement into the soil below) can cause cracks in the drywall. Drywall, paint and other wall materials are more brittle and less flexible than your home’s framing. As such, while the frame of your house might be well equipped to handle settling or even seismic activity, the drywall doesn’t have the same luxury. The brittleness of drywall explains why drywall will often crack during or following earthquakes—even in structurally sound homes.
Why do my windows stick?
As with drywall cracks, there are several reasons that a window can become stuck. If the wood frame of the window gets wet, it can warp and expand, thereby making the window difficult to open or close. Humidity can cause a similar issue with wood expansion. Your home’s settling can play a role as well, and seismic activity can only exacerbate the problem.
Why is my floor not level?
If your floors aren’t level, the issue could be a sign of differential settlement of foundation elements or a rotting sill (the wooden layer between your home and your foundation). Seismic activity, however, can accelerate a home’s problem with even leveling.
In general, if you notice cracks in the drywall, sticking windows or doors, or uneven floors—particularly after an earthquake—you should call a qualified inspector to perform a structural inspection of your home. It’s very possible that the issues are due to the seasonal expansion and contraction of the soils on which your foundation, or other causes that you can’t do much to prevent. However, it’s also possible that these problems are the earliest signs that your home’s foundation and structural integrity have been compromised by seismic activity. A qualified structural inspector can assess the severity of the problem and recommend measures to repair the wear and tear and prevent additional damage in the future
Is my home structurally sound for a renovation?
If you are considering a renovation of your home, it is vital to know whether any serious structural problems might render a renovation dangerous. Provided the foundation and framework of your home are structurally sound; you should be free to pursue any renovation you please. However, since the definition of “structurally sound” is different in zones with high seismic activity, it is a good idea to have a structural inspection and evaluation done before you make any plans to remove walls, add second-story additions, build onto the back of the house, or remodel your kitchen or bathroom. In most cases, a seismic design is prepared only for the area subject to the renovation, and all other areas of the home are assumed adequate in their existing condition. After all, chances are your home has already been through multiple earthquakes, and it’s still standing…
Is this a bearing wall?
In particular, if you are considering any renovations or remodels, it is important to identify which walls in your home are load-bearing walls and which are not. Bearing walls are key components of your home’s structural integrity, which means they can’t be removed without leaving your home vulnerable to structural failure. Non-load bearing walls merely form divisions between rooms; they don’t bear the structural load of the house. To find load bearing walls, start at the lowest point of your home—usually the basement—and look for walls with beams that go directly into the foundation. Usually, walls that run from the lowest point of your home to the roof are load-bearing walls. Walls that are only present on one floor and do not have a continuous load path to the building foundation are typically non-load bearing walls. A structural evaluation can help you identify your home’s load bearing walls.
Getting Help from Professionals
If you need a home inspection or you are worried about potential structural problems, it’s best to seek help from experienced professionals. Hogan Land Services is located in Santa Rosa, Santa Cruz, and now in Livermore. We are a dedicated team of Professional Engineers and Land Surveyors who are committed to helping clients assess and improve the value of their property, streamline projects, and advocate for our clients with local governing agencies. If you have any questions please connect with us at (877) 544-2104 or complete this contact form to setup a free consultation.
Topics: structural engineering