According to the California Earthquake Authority, there are approximately 15,700 known fault lines in the state of California, with new ones being found every year by scientists. Of these 15,700, more than 500 are still active. The same authority has also indicated a greater than 70% chance of an earthquake of Magnitude greater than 7 striking Mountain View, Palo Alto, San Francisco and other neighboring localities and counties. Clearly, the ever-present threat of seismic activity, has the potential to directly affect the safety and structural stability of buildings in the area.
Many newer buildings in the area are constructed keeping the threat of an earthquake in mind. However, a lot of buildings, especially older, residential ones, are not fully equipped to deal with even a mild earthquake. Typically, the buildings that fall into this category are soft-story structures.
Soft Story Buildings:
A soft story building is quite a common structure, that was originally built between the 1960s and the 1980s. Any building with more than one story, that has windows, wide doors, openings or large spaces where a shear wall might be needed for structural strength is a soft story building. A typical soft story building could be one of the following:
Retail buildings where the front fascia is constructed with glass
Ground floor parking under wood framed apartments
Multi-storied, multi-use buildings typically have a well supported 1st floor, however the floors above the 1st floor are usually considered as soft story structures as they are usually propped up and constructed with wooden flooring.
These buildings have one or more structurally critical spaces that do not have the same level of reinforcement as the other floors or sections within the building.
In June of 2019, the Mountain View City Council created a proposal that would look to retrofit aging residential buildings, that are thought to be at risk of severe damage, in the face of a major earthquake. The plan suggests the implementation of the retrofit program start with the larger buildings over the course of 6 years.
The retrofit program primarily targets soft story buildings in the region. The plan to retrofit earthquake-risk buildings in the Mountain View locality follows similar plans drafted for counties and localities such as Oakland, San Francisco and Berkeley. As a part of the plan, the council has also decided to spend $150,000 in city funds on hiring a structural engineering firm to complete an assessment of structures that are at risk in Mountain View.
The responsibility of retrofitting structurally unsafe buildings will be with the landlords and/or property owners. This obviously raises several questions – How much do seismic retrofits cost? How do landlords recover the costs? What is the process of distributing the costs incurred by the mandatory retrofits? Etc.
This article will try and answer some of these questions in the following sections.
How do I know if my house or residential building needs to be retrofitted?
The easiest way to check is to see if your house was built before 1982. If it was, it’s best to have the building retrofitted as soon as possible. The Mountain View council has identified close to 490 buildings that can be categorized as ‘At Risk’. The first wave of structural corrections and strengthening practices came in 1982, when the University of California released a report recommending specific building practices to prepare for an earthquake risk. Since then, multiple inter-governmental reports and private agency recommendations have added to the body of knowledge. A significant amount of change to the building standards occurred in the 1990s as well. It is probably best to have your home assessed by an expert (A state certified structural/civil engineer) to know definitively whether your home needs retrofitting.
How much does a complete residential retrofit cost?
The short answer to this question is that there is no specific answer or number. The cost really depends on the size of the building, the number of floors, the number of dwelling units and the current structural state of the building. The typical cost of a retrofit also varies from locality to locality and county to county. Some real estate developers predict that costs could range from $6,000 - $20,000 per unit or $25,000 - $100,000 per building. The typical cost to retrofit a medium sized home with one floor level, a crawl space area relatively free of obstructions, with wooden framed walls/cripple walls can range from $6,000 to $12,000.
How do Landlords recover their costs?
The answer to this question is also conditional. While landlords and property owners with diversified incomes may be able to pay for the costs of these mandatory retrofits, landlords who rely on rental property income area as their primary source of income will find it much more difficult. What this could mean is that landlords and property owners could pass on the cost of the retrofit to their tenants. Under the Community Stabilization and Fair Rent Act (CSFRA) in Mountain View, landlords can increase rents to above the maximum allowed increase, but only after they’ve proved that the property owner is not receiving a fair rate of return on their property to the housing department.
However, this process is still a little tedious and has not been made clear to many. It is expected that the Mountain View council will think of and implement regulatory methods through which property owners can protect themselves during the rollout of the mandatory retrofit. In any case, a house or residential building that is fully code compliant and has had a code compliant seismic retrofit done will have had its value most likely increase in the market.
Can I do the retrofitting myself?
While it isn’t impossible for an individual to complete the retrofitting themselves, it is advised that homeowners and property owners work with an experienced team of professionals. Often, the workload associated with retrofitting an entire building overwhelms even the most experienced individual. Additionally, even if the homeowner is confident in their abilities, it is usually more economical to hire a structural engineer to determine the number and size of the shear walls needed and the number and points at which to install hold-downs in the existing foundation.
Contact & Conclusion:
Seismic retrofits are critical in ensuring human and public safety, especially with regards to older buildings. If you live in Mountain View and you want to know if your building, home or property requires a soft-story retrofit, it is best to speak with experts from the industry or from The Department of Building and Safety. At Design Everest, we are a One-Stop Pre-Construction service provider and can take on your project anytime. You’ll have access to the best structural engineers, architects and project managers! Our team will help you navigate the process of retrofitting your home from start to finish.
Feel free to give us a call at 877-704-5687 and we will be more than happy to guide you through the process of getting your home/building seismically retrofitted.
-Anne R, past client with a seismic retrofit project.
*Note: The content published above was made in collaboration with members of Design Everest.