Portland Seismic Retrofit Guide: Earthquake Readiness
Updated 06/2024.
Our awareness of the threat of seismic activity in the Portland area grows each year, causing increasing concerns for sellers and buyers. Recent studies show that at least one local fault is more active than previously thought. This discovery also increases the likelihood that other faults may put Portland at more risk for an earthquake. But there is good news: along with increased risk comes more ways to confront the problem.
Better, more comprehensive maps help us understand where the most vulnerable spots are. Seismic retrofitting also makes homes better equipped to handle an earthquake.
Thankfully, Portland is once again ahead of the curve in educating its populace about how seismic retrofitting works and how to implement it. Let’s take advantage of that and dive into our best information on seismic retrofitting practices and earthquake preparedness.
How to You Know If Your Home Needs Seismic Retrofitting
In 1974, Oregon adopted its first statewide building codes. That might lead you to believe that all homes built since then are good to go regarding the threat of earthquakes. Though homes built before 1974 are indeed at greater risk, the 1974 code wasn’t updated with seismic activity in mind until 1993. So, while homes built between 1974 and 1993 are more likely to withstand an earthquake, they may require substantial retrofitting. Only homes built after 1993 can guarantee seismic safety features.
Buyers looking at homes built before 1993 should ask the inspector to assess whether retrofitting exists. Sellers may want to consider doing the retrofitting before listing. And if you do choose to retrofit, advertise it!
Why Is Seismic Retrofitting Important?
According to the Oregon Construction Contractors Board, earthquakes can affect a home in three ways:
● The house can slide off its foundation
● The cripple walls (walls between the foundation and floor) may buckle and collapse (aka racking)
● The house may be lifted off the foundation
While reducing your risk to zero during an earthquake or seismic event is impossible, seismic retrofitting can help mitigate potential damage. As one saying goes, “Earthquakes don’t kill people; buildings do,” meaning ensuring your home or business is properly up to code can greatly improve your safety and the safety of others.
New research comes out each year that helps people develop building codes. These codes increase the security of buildings and make catastrophic failures less likely to occur. Many of these codes come from the International Code Council (ICC), which includes the International Building Code (IBC), the International Resident Code (IRC), and the International Existing Building Code (IEBC).
By following the codes created by the ICC and local and state seismic building codes, you can ensure your home is less likely to suffer a catastrophe during a seismic event. Catastrophes tend to happen in areas of your home with less support, such as weakened walls, loose foundation points, or supporting walls that need to be adequately secured. By having your home properly inspected and fitted by a seismic retrofitting professional, you can ensure that these risk points are adequately secured.
Older homes, especially those built before specific codes were implemented in 1974, can be at higher risk for catastrophic failure during a seismic event. It’s essential to have these homes checked by a licensed professional so you can take the necessary steps to safeguard your home against potential disaster.
What Constitutes Seismic Retrofitting in Portland?
At this point, you may be wondering, “Okay, but what would a contractor actually do to protect my home from an earthquake? First, let’s talk about what happens during a significant seismic event. When the ground shakes violently enough, it can cause walls to crack or a home to slide sideways off of its foundation. So, the main focus of earthquake retrofitting is to attach the home to its foundation as securely as possible.
How do we do that? Luckily, Portland, in particular, has a specific guide to help you. Their Bulletin 12, “Residential Seismic Strengthening: Methods to Reduce Potential Earthquake Damage,” clearly outlines what contractors can do. Portland is the only area in Oregon that has created such specific standards. These standards are intended only for homes that meet specific criteria, which you can review in the bulletin. The big takeaway is that the guide pertains to one- to two-family homes with a concrete foundation that is three stories high maximum. Outside of these parameters, an engineer would need to get involved.
If you meet the criteria, though, there are three basic improvements to investigate.
#1 – Bolting the House to the Foundation
In homes built before 1993, the house is often not securely attached to the concrete foundation. A retrofitting contractor can come in and bolt the house itself to the foundation. The wooden frame that sits on the foundation is called a mudsill. It only became common for builders to bolt the mudsill into the concrete in the 1960s. And even then, not everyone did so. According to the Portland government’s bulletin, bolting the mudsill is the most important and cost-effective way to increase structural strength.
#2 – Reinforcing the Cripple Walls
The second most common structural weakness is poorly constructed cripple walls. Cripple walls connect the mudsill/foundation and the home’s actual flooring.
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Often older homes often use stucco or wood siding to brace cripple walls. These materials will not protect against earthquakes. A retrofit would require adding plywood to properly support the home’s cripple walls.
#3 – Adding Water Heater Strapping and Automatic Gas Line Shutoff
Portland’s building code requires hot water heaters to be strapped and secured for safety in a seismic event. While many homes already have water heaters secured to wall studs, an older home may need additional strapping for higher security. Also, your chimney may need securing or renovation during a seismic retrofit depending on its age, height, and other factors.
Another solution not required by code is automatic gas shutoff. During a seismic event, this shutoff automatically shuts off the gas to your home, preventing a gas leak should pipes become damaged. While this does not guarantee you’ll have no gas line issues after an earthquake, it does safeguard your house from potential further damage in the event of an earthquake or other seismic event.
How Much Does a Seismic Retrofit Cost in Portland?
Unfortunately, there’s no easy answer to this question. The cost of a retrofit will depend largely on your home’s condition. Will you need to both bolt the mudsill and reinforce the cripple walls? And size matters. A larger home with more square footage of foundation will inevitably run at a higher price point.
To give you an idea, Oregon’s guide to seismic retrofitting estimates a cost of $4,000 to $10,000 for a single-floor, 2,000-square-foot home. The cost of retrofitting might make you pause. Still, you may qualify for financial assistance, which we discuss in the next section. Even if you don’t, consider the cost benefits in the long run. Seismic retrofitting inspires a huge amount of confidence in the home for prospective buyers and increases your home’s value accordingly. But whether you’re buying, selling, or planning to keep your home for life, being prepared for an earthquake could save lives.
When looking for a contractor, we recommend getting bids from at least three companies to ensure a fair price. Check out Portland’s tips for finding a contractor.
Seismic Retrofitting Incentives and Financial Assistance
The City of Portland set aside federal funds to retrofit 150 homes, so if you plan to buy, you benefit from knowing if the home is one of them. Additionally, income-producing properties listed in the National Register of Historic Places can receive federal tax credits for retrofits. Contact the Oregon State Historic Preservation Office for more information.
You can take advantage of tax exemptions to implement seismic safety measures. As for grants, The City of Portland prioritizes retrofits for public buildings to safeguard the maximum number of individuals per dollar. When grants pop up in the future, we will list them here.
Seismic Retrofitting Is Important, But It Won’t Earthquake-Proof Your Home
No matter how diligently constructed it may be, no home is earthquake-proof. Seismic retrofitting will minimize the damage to your home in the event of an earthquake. We’d still recommend taking out earthquake insurance as well. In a 2017 study, the Oregon Seismic Safety Policy Advisory Commission determined that Oregon’s earthquake insurance industry compares positively to the market in California in terms of affordability. While earthquake insurance doesn’t replace retrofitting, it can bring peace of mind and security.
Some homeowners purchase insurance instead of retrofitting, but insurance will not safeguard against damage to homes or people. You may also be required to show proof of retrofitting before you are accepted. Either way, doing both ensures you are ready when tragedy hits.
Additionally, it is a good idea to be prepared for an earthquake in a broader sense. April is the Portland Bureau of Emergency Management’s earthquake preparedness month. So take a moment to check out their resources, which will help your household to have a plan and an emergency kit ready, just in case. And just last month, the earthquake early warning system ShakeAlert™, created by the U.S. Geological Survey, became available in Oregon. Take advantage of these services alongside retrofitting and insurance to stay ahead of the curve in earthquake preparedness.
Talk With a Real Estate Expert
Whether you’re getting your home ready for the market or evaluating a new home you’ve got your eye on, our top selling and buying agents can help. If you have questions about the Portland real estate market or want a professional opinion, our team of top 1% buyers’ agents can help. Feel free to reach out today with any questions about purchasing or selling a Portland home.
