The most important criteria for selecting a seismic retrofit contractor would rank as follows:

Will your contractor use a calculator to determine lateral loads, or merely count to 4 – as in following a prescriptive path such as Portland’s “Seismic Retrofit Program”?

Is your contractor a seismic retrofit contractor, or a contractor who also does kitchens, radon, fences…? We would highly recommend a contractor who does seismic retrofit work exclusively and has done it for a very long time. Word of warning, there are only 3 contractors in Portland who fit this description, but no end to the number of contractors who install seismic retrofits “all the time.” Some of these contractors even make claims to “live and breath” seismic retrofitting, yet have only been in business for a few months.

Does your contractor understand how earthquake forces impact buildings, and how to mitigate them, or do they reassure you with “but you’ll qualify for earthquake insurance”? The field just narrowed.

Does your contractor know the difference between a holdown and an anchor bolt? Go ahead and ask them – it’s important!

Typically, no. Occasionally for pre-sale estimates, we’ll charge a small amount, but apply it to any work that may take place if the sale goes through.

While this work will make your house much less likely to suffer serious damage in an earthquake, there are so many other factors to consider, including the specific geology under your house and soil saturation level at the time of the earthquake, distance from the epicenter, depth of the earthquake, ground force acceleration, type of earthquake (shallow fault, subduction zone…), etc. The standards for methods and materials were derived from analysis of previous destructive earthquakes – what made the difference between houses that survived the quake and houses that didn’t, and what was the specific cause of failure. The materials and methods have been shown to be effective at resisting lateral forces, but the results tend to be anecdotal rather than predictable. Even if an earthquake damages your home, this work may make the difference between your family living in the home while repairs are performed or living in a FEMA trailer (our biggest fear).

No. This work is technical and should be performed by a contractor who has the ability to calculate the loads and design a retrofit specifically for your house. We will always use off-the-shelf hardware when we can, but the manufacturers have strict specifications, and frequently we encounter conditions that don’t meet those spec’s. In that case, it’s very important to understand the physics of earthquakes, and the engineering of a seismic retrofit, in order to be able to come up with an alternative approach to off-the-shelf hardware. Sadly, we re-retrofit about one house a week. It’s bad enough that the homeowners had to pay for a retrofit once, but twice?

Home inspectors are beginning to note potential issues with seismic retrofits on their inspection reports. We’ve stopped several home sales from being completed due to the high cost or limited effectiveness of retrofitting particular houses (crumbling foundations, multiple additions…). When comparing houses, all else being equal, the retrofitted house will most likely sell first, and for more money. And for some houses, they won’t sell until they are retrofitted.

There are ways to retrofit these foundation systems, but they’re relatively expensive.

Yes, either by temporarily removing parts of the finished interior wall or by removing siding and installing from the outside. Either way, we’ll replace finishes to an “as-found” condition.

Most insurance companies now require homes built prior to 1976 be retrofitted before extending coverage for earthquakes, if they offer it at all (and there are fewer every year). There are a small number of companies that offer earthquake insurance for houses in Oregon, Washington and California, without a retrofit. And while a least some of these companies are highly rated, this is their entire portfolio, which calls into question the sustainability of their business model. At the end of the day, we all have our own level of risk tolerance. Some of us retrofit our houses. Some of us have insurance. And many of us do both.

Yes, there is. We can install a Northridge valve that will cut off the gas to your house in the event of any significant shaking.

That would depend on our workload at the time. Give us a call and we’ll see what we can do to accommodate you.

Essentially, we will provide exactly what we are able to given what your house needs, nothing less. We’re primarily focused on preventing failure in the areas where the highest loads in an earthquake occur. In most residential homes, this is where the house sits on the foundation. Often, work above that level would be to mitigate the effects of a soft-story condition (also known as a weak-story condition). Some houses were built, or remodeled, with too many openings on a given wall, which can render it too weak to support the lateral loads imposed by living space/roof on the floor above, in these cases a basic retrofit becomes more complex. 

Ultimately it depends on a number of variables including size and construction of the house, the number of workers on site, and job-specific obstacles. Often it takes 1 day for an unfinished basement or crawl space, 2-3 days for houses with cripple walls, and about 1 week for finished basements. Sometimes we need to reverse-engineer houses that were designed to maximize views and were built prior to a building code revision in 1994 to determine the designed load values and then re-engineer the structural design to get closer to meeting the current code requirements, and these can be somewhat drawn out projects.

Yes. We use heavy, noisy tools and equipment to drill holes and drive bolts through your concrete foundation. We use compressed air to blast the concrete dust out of the drilled holes, and we use nail guns for hours on end. While your neighbors are unlikely to complain, you might want to be somewhere else than home during the immediate hours we’re performing the work.

There is none. Portland has a “seismic retrofit program,” as do other jurisdictions on the west coast, including Seattle (Project Impact), the Association of Bay Area Governments (Plan Set A), and Los Angeles (Earthquake Brace and Bolt) which relies on “prescriptive path,” or rule-of-thumb (also known as Retrofitting for Dummies). There is no math involved in the retrofit design, and it fails to take into account the shape of the foundation (see the question: “I read that anchors need to be 4’ apart. Is that what you do?”), among other glaring omissions.

No, we use an engineered equation to determine the lateral loads for your particular house, and the amount of hardware, or resistance, will be equal on all 4 wall lines. If your house is square, the spacing will be equal on each wall. If it’s rectangular, the hardware will be closer together on the short walls and further apart on the long walls. 4’ spacing refers to something called “prescriptive path,” the origins of which can be traced to a committee set up by the Association of Bay Area Governments after the Loma Prieta earthquake (it included engineers, contractors and, not surprisingly, hardware manufacturers, and it went on for 5 years), and is really just “rule of thumb.” It works occasionally on square houses with wood siding and cedar or comp roofing, no additions, few sill plate splices and no more than two floors above the basement or crawl space level.

Either. Surprisingly, the cost tends to be fairly equal, whether we do it from the inside or outside, due to the increased load rating, or strength, of exterior hardware, and exposure to the elements, even when we need to demo and repair the interior finishes. The latter requires hardware that’s either hot-dip galvanized or stainless steel. The flat hardware we use on the exterior, the Simpson FRFP, has a 20% higher load rating than that of the interior hardware, Simpson URFP. As a result, we need to use more of the interior hardware to achieve the same result.

No, they are just as regular now as when geologists began tracking them. The difference is that a lot of people happen to live in Haiti, Chile and on the California/Mexico border. And as populations grow, the chances of major natural catastrophes of all types will increase. Here in the NW we are particularly vulnerable due to our abundance of bridges. Portland is bound by the Columbia to the North, with the Willamette running through the middle. Access from the East is highway 84, with its many bridges, and from the South more bridges than I can count. If the Cascadia Fault ruptures all the way from Northern California to BC we could go some time before help arrives.

Posts are great at supporting vertical loads, in a static condition (no earthquake).  But in an earthquake, basement foundations act as both a retaining wall (resisting very high soil loads trying to implode the basement walls) and somewhere for the lateral loads to go.  When the walls implode, even though that force itself isn’t enough to keep the multiple steel posts from kicking in, with the walls and soil gone, there’s nothing left to buttress the posts and they’ll fall over.