Marin – Earthquake Retrofitting

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(415) 523-5725
(415) 523-5740

Serving all of Marin County and the Bay Area including San Rafael, Novato, Mill Valley, Larkspur, Corte Madera, Fairfax, San Anselmo and Sausalito.

Services include construction planning and design, custom home building, multi-family housing,residential facilities, hotel and school construction, tenant improvements and commercial building services.
License 866058 | DCID4156022133

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Why Trust Diamond Certified Earthquake Retrofitting Companies Rated Highest in Quality?

By augmenting structural stability, earthquake retrofitting represents a proactive step for safeguarding your home investment. You can feel confident choosing an earthquake retrofitting company listed above because each has been rated Highest in Quality and has earned Diamond Certified. For more information on how best to choose and work with a retrofitting contractor in Marin County, read the following articles. Photo: BB & B Builders Inc (2014)

You are the customer. If your goal is to choose an earthquake retrofitting company that will deliver high customer satisfaction and quality, you’ll feel confident in choosing a Diamond Certified seismic retrofitting contractor. Each has been rated Highest in Quality in the most accurate ratings process anywhere. And you’re always backed by the Diamond Certified Performance Guarantee. Here’s why the Diamond Certified ratings and certification process will help you find a top-rated earthquake retrofitting contractor and is unparalleled in its accuracy, rigor and usefulness:

1) Accuracy: All research is performed by live telephone interviews that verify only real customers are surveyed, so you'll never be fooled by fake reviews.

2) Statistical Reliability: A large random sample of past customers is surveyed on an ongoing basis so the research results you see truly reflect a Diamond Certified company’s top-rated status.

3) Full Disclosure: By clicking the name of a company above you'll see the exact rating results in charts and read verbatim survey responses as well as researched articles on each qualified company.

4) Guaranteed: Your purchase is backed up with mediation and the Diamond Certified Performance Guarantee, so you can choose with confidence.

Click on the name of a Diamond Certified company above to read ratings results, researched articles and verbatim customer survey responses to help you make an informed decision.

More than 200,000 customers of local companies have been interviewed in live telephone calls, and only companies that score Highest in Quality in customer satisfaction–a 90+ on a 100 scale–as well as pass all of the credential-based ratings earn Diamond Certified. By requiring such a high score to qualify, the Diamond Certified program eliminates mediocre and poorly performing companies. Read detailed information about the ratings and certification process.

How to Choose
Do You Need Earthquake Retrofitting in Marin County?
Reinforcing your home's structure provides added protection against earthquake damage. Photo: BB & B Builders Inc (2014)

You know that you live in earthquake country when you live in the Bay Area, including Marin County. We all know the area’s vulnerabilities, whether we are talking about seismic retrofitting of bridges or our own homes and businesses. No matter where you live in Marin County, in San Anselmo, San Rafael, Larkspur, Mill Valley, Novato, Sausalito, Corte Madera, or Fairfax, you want to keep your house safe. But how do you do it? How do you make sure that your structure will withstand the next earthquake - or the big one? One approach is to get seismic retrofitting for your home....

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You know that you live in earthquake country when you live in the Bay Area, including Marin County. We all know the area’s vulnerabilities, whether we are talking about seismic retrofitting of bridges or our own homes and businesses. No matter where you live in Marin County, in San Anselmo, San Rafael, Larkspur, Mill Valley, Novato, Sausalito, Corte Madera, or Fairfax, you want to keep your house safe. But how do you do it? How do you make sure that your structure will withstand the next earthquake - or the big one? One approach is to get seismic retrofitting for your home. Some call it bolting and bracing. Earthquake preparedness for the house focuses on keeping the house intact and on its foundations. While building codes call for more modern structures to have better earthquake resistance built in from the ground up, you may still find it worth your while to call in earthquake retrofitters to take a look so you are as ready as you can be. Our discussion now will focus on homes, rather than offices or other buildings.

Seeking out Proper Earthquake Retrofitting in Marin County
Finding good earthquake retrofitting can seem like quite a task, for a couple of reasons. First, there is no code in California specifically for earthquake retrofitting that you or a contractor must follow. There is a seismic retrofit code, but it is not mandatory and it is only for simple constructions on flat land. However, there are mandatory building codes. Changes made as part of an earthquake retrofit must conform to those building codes, but there is no specific mandatory code describing earthquake preparations for the house. This is partly because houses come in many different varieties in Marin County, whether in San Anselmo, San Rafael, Novato, Mill Valley, Larkspur, Sausalito, Belvedere, or Tiburon. A single-level building built on the flat is much easier to secure than a multi-level house built on a hillside. This set of circumstances means that any retrofitting you do is done on a purely voluntary basis. One slight caveat to this is that some homeowners find they cannot get an insurance policy for a newly purchased house or renew an insurance policy on an existing house without some evidence of earthquake retrofitting being provided to the insurer. So you may not be retrofitting entirely voluntarily, but you are as far as the state is concerned.

Earthquake retrofitting is also daunting because the contractors who perform it do not have to pass a test that specifically addresses earthquake retrofitting. Yes, you will need a licensed contractor. Anyone who does more than $500 of work on your house must be a licensed contractor. But though California has many different categories for licensed contractors, there is no specific category for earthquake preparedness contractors. Your best choice is to look for contractors who have experience with earthquake retrofitting. You could also consider working with an engineer to draw up plans to retrofit your house. If you do look for an engineer, you should again look for one who specializes in earthquake retrofitting.

You will need a building permit to complete the earthquake retrofit. Building permits are required for work done on the foundation, where much of the earthquake retrofitting occurs. Some counties and areas waive the fees for the permits because there is no code, but most require the usual fees and processes to get a building permit for earthquake retrofitting work. Your earthquake retrofitting company should be able to help you get the permits. You should be aware that a final building inspection is required for the sign-off on the building permit after the project is complete. The building inspector will look at the entire building, not just the area where the earthquake retrofitting is done. Because of this, it’s a good idea to install the required smoke detectors in bedrooms and hallways before the final building inspection.

That’s not to say the state doesn’t care about the effects of earthquakes. In fact, earthquakes in Loma Prieta and Northridge have drawn much study. Based on observations made at houses after those earthquakes, building codes have been updated, and more information is available about features that help a house survive an earthquake better.

A set of plans is key to an effective earthquake retrofit. The plans form the basis for the bid amount. The plans may be drawn up by an architect or engineer. Or, the plans may be drawn up by the contractor. The contractor can draw up the plans when the changes are simple enough that the prescriptive standards can be applied. The plans should be submitted to the local housing authority when the permit is requested, so that the plans can be reviewed. The housing authority decides if the prescriptive standards are enough, or if a set of drawings from an engineer or architect is needed.

What Exactly Does Earthquake Retrofitting my Marin County House Entail?
An earthquake moves the ground under a house, placing forces on the structure. Weak points in the structure can collapse. Chimneys, porches, or other less-well attached parts can separate. The house can even slide off its foundation. Earthquake retrofitting attempts to prevent significant damage to structures during an earthquake. No house, anywhere in Marin County, whether in San Anselmo, San Rafael, Novato, Larkspur, Mill Valley, Dillon Beach, Kentfield, or Marshall, can be made earthquake proof. But retrofitting can mitigate the damage from an earthquake.

The primary forces that cause damage are the horizontal forces. To prevent damage from horizontal movement, materials are used to create a continuous load path that passes the motion load from the house back into the foundation and the ground. The load path runs from the roof, through properly enforced walls, to the floor, and down to the foundations. The load path may not have any breaks in it if it is to transfer the load successfully. The load path must have connections at every transition – from the roof, which connects to the walls, which connect to the floors, which connect to the cripple wall, which connects to the foundation. Only when this load path is complete and intact can the energy pass successfully down the path and to the ground.

So, how can you ensure that your house has a continuous load path? Seismic forces are strongest at the base of your house, and much of the earthquake retrofitting you will find focuses on this area of the house. Of course, this assumes that your roof is in good shape and can withstand the forces of an earthquake. It is axiomatic that any changes you make in the course of earthquake retrofitting must not harm the existing buildings. Buildings can usually withstand vertical movement because all houses are built to resist gravity. The gravity-resisting features include transferring load from the roof to the walls and from the floors to the cripple walls and foundation. (Cripple walls refer to walls that go from the foundation to the first level of the structure.) The earthquake retrofitting must work in concert with some of this existing gravity-resistance system.

Earthquake retrofitting revolves around strengthening and stiffening the walls, and making sure the house is well connected to a sound foundation. To brace the walls, your retrofitter will create shear walls. Shear walls are reinforced walls that have the stiffness and strength needed to resist the forces of an earthquake. Shear wall retrofitting consists of framing, sheathing, fasteners, and hold-downs. These elements are combined to create a structure that can resist the forces caused by an earthquake. A long, low shear wall resists forces better than a tall, narrow shear wall. Shear walls should be installed to form a box and should be equal in length and should be placed symmetrically on the four exterior walls of the building. Shear walls should exist on each level of the structure, including the crawl space. In some cases, you may need interior shear walls, when the exterior walls lack strength and stiffness, or when the dimensions of your shear wall box exceed 3:1. For example, if the width of the building is 15 feet, you would not have to worry about interior shear walls unless the length is greater than 45 feet.

Framing with the appropriate lumber is the first step in making the shear wall. In existing homes, these framing studs sometimes already exist. However, newer building codes may dictate that more studs be added so that they are closer together. Between each stud, a block is placed at the bottom, so that the sheathing can be attached to it. In California, the framing material is assumed to be Douglas fir-larch. If you find that your framing material is redwood or hem-fir, you must make sure that the design of your retrofit accounts for this. Douglas fir-larch is denser, which makes it better able to hold fasteners like nails.

Once the framing material is in place, sheathing material is nailed over it. The building codes allow different sheathing materials, but after the Northridge quakes, it’s been determined that plywood is the best material for resisting earthquakes. Plywood less than four layers thick tended to pull apart, so most often, five-ply plywood is best for earthquake retrofitting. The plywood sheathing material should have ventilation holes in it when installed in the cripple wall.

Plywood must be attached using the proper fasteners. Your contractor should use nails, rather than screws, since nails are easier to install than screws and are better able to conduct seismic energy than screws. There are building code regulations for the types of nails used and what a properly installed nail looks like and how closely the nails must be inserted to each other. You should look to see that nail heads are flush with the surface of the sheathing. The nails should not be too close to the edge of the sheathing. The nail should never cause a split in the sheathing material – split material is weakened material. The shear wall ends where the hold-down device is installed. These hold-downs are bolts or other devices used to hold down the installed sheathing. The length of the shear wall is measured as the distance between the hold-downs. The hold down should always be installed as specified by the manufacturer – never contorted or improperly placed.

This is a general description of shear wall installation in a wooden building. Framing is installed, and plywood is nailed to it. The framing includes not only lumber going up the side of the wall, but also blocks that are installed at the foot of the wall. These blocks are the subject of some discussion. In older houses, there is a short wall, called the pony, or cripple, wall. This wall exists between the ground and the floor of the first level of the house. It is less than a full storey high. This cripple wall sits on top of a piece of wood, called the mudsill. The mudsill is lumber that sits on top of the foundation. The blocks installed as part of the retrofit are used so that the plywood has something to be nailed to at the base of the wall. However, despite some civic authorities recommending attaching the blocks using nails, it’s been noticed that doing so can split the block.

There are some alternate techniques. One uses staples to attach the block to the mudsill. Another technique is to attach the block to the plywood first, then attach the assembled piece to the cripple wall and mudsill. A final technique that is gaining some recognition is the flush-cut mudsill. In this scenario, the mudsill is cut back so that it is flush with the two-by-four studs used to build the house. The plywood is then nailed directly to the freshly cut mudsill. In cases where a shear wall cannot be applied, you may need to get a moment wall. This is a steel-framed structure designed by an architect or engineer.

Getting the Proper Foundations in Marin County
You may also need to do some work on your foundation as part of the retrofit. There are several ways to achieve more sound foundations. You may cap your foundations, create parallel structures, or replace the foundations. If you choose to cap the foundations, a concrete cap is poured over the existing foundation wall. New steel anchor plates and bolts are installed to attach the foundation to the lumber that supports the floor above it. If you plan to replace the foundation, the building is often propped up so that workers can replace the foundations in four-to-six foot sections at a time. A parallel foundation system may also include placing columns under the flooring joists. The columns are often placed next to a wall. The column is better able to resist the earthquake forces. Some of these foundation techniques may require a firm that specializes in foundation work.

A common approach to retrofitting a foundation is to install bolts. In houses without cripple walls, the house is bolted directly to the foundation. In this scenario, the bolts pass through the mudsill (the wood sitting on top of the foundation) and into the foundation. Building codes require bolting. However, bolting may not be sufficient to keep the house from slipping. Bolts are often installed with holes that are bigger than bolt. During an earthquake, the bolts may move in the holes, tearing at the mudsill. To prevent problems, you may install more bolts. You may also install foundation anchors. Foundation anchors also join the mudsill to the foundation material. In some cases, you may also want shear transfer ties. Shear transfer ties prevent the floor joints from sliding off the mudsill. When the floor joints are perpendicular to the mudsill, they are usually properly nailed to the mudsill and no transfer ties are needed. When the floor joints run parallel to the foundation, they may not be sufficiently nailed and may need shear transfer ties.

You may have to decide between using mechanical or adhesive bolts. When the bolts are installed, they may be installed with a washer or with plates, or with a plate washer. If a washer is used, it must be a square washer, as round washers do not perform as well in earthquakes. A mechanical bolt can only be used with concrete, not with masonry. The mechanical anchor must be used in good-quality concrete, since it attaches to the concrete via friction by expanding. An adhesive anchor uses a chemical bond to attach to the concrete. The adhesive bolts usually cost a bit more. With adhesive anchors, it’s very important that the hole be cleaned because the chemical bond needs to be formed with the concrete of the foundation, not any particles left in the hole.

You should be cautious if you see bolts that are countersunk – in most cases, this is unacceptable installation. A countersunk bolt is one that is inset into the material – if the wood is gouged away so that you can reach the bolt and washer, this is generally considered an improper installation.

A Few Special Considerations in Marin County for Earthquake Retrofitting
Keep a few things in mind for your earthquake retrofitting. Houses built after the 1990’s are likely to have the most up-to-date earthquake preparedness, since building codes were updated after the Northridge earthquake. However, you might want to have a check, since not all builders build strictly to code. If your house is a special case, and a surprising number of homes in Marin County qualify as special cases, whether in San Anselmo, San Rafael, Larkspur, Mill Valley, Novato, Kentfield, Marshall, or Dillon Beach, you may need more than a contractor to design your retrofit. Houses on hillsides, multi-storey houses, houses with large openings like garage doors, all may need special plans from an engineer or architect. A good contractor will be upfront with you about when you need to call in additional expertise.

Do not allow plumbers, heating, ventilation, and air conditioning contractors, or others, to make large openings in the shear wall. Openings or cutting into the shear wall will weaken the wall.

This discussion has centered around standard framing methods. Some houses are built using balloon framing. These houses usually require engineer or architect plans to ensure that the seismic retrofit is properly planned.

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Know What You Want
As You Decide if you Want Earthquake Retrofitting in Marin County

You want your Marin County house, whether in San Anselmo, San Rafael, Larkspur, Mill Valley, Novato, Kentfield, Marshall, or Sausalito, to be safe, to be a good example of earthquake preparedness. You don’t want to invest in a lot of work that will end up doing no good. It’s a good plan to draw up some basic questions that you can ask yourself. Once you narrow down what you want, you’ll find it easier to work with earthquake retrofitters. It’s ok if you can’t use exactly the right industry term....

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You want your Marin County house, whether in San Anselmo, San Rafael, Larkspur, Mill Valley, Novato, Kentfield, Marshall, or Sausalito, to be safe, to be a good example of earthquake preparedness. You don’t want to invest in a lot of work that will end up doing no good. It’s a good plan to draw up some basic questions that you can ask yourself. Once you narrow down what you want, you’ll find it easier to work with earthquake retrofitters. It’s ok if you can’t use exactly the right industry term. Just know your house and what you want, and you’ll be able to work together to get what you want.

  1. Do I want a Diamond Certified company that is rated best in quality and backed by the Diamond Certified Guarantee?
  2. What kind of earth does my house sit on? Is it more susceptible to liquefaction?
  3. Do I know of any problems with my foundation or house’s structure, or am I just concerned in general?
  4. Do I just want to satisfy the basics that an insurance company is demanding that I complete before renewing a policy?
  5. Do I live very close to a fault?
  6. Do I live on a hillside? Or do I have a multi-storey home?
  7. When was my house built?
  8. Does my house have a cripple wall (aka pony wall)?
  9. Is my foundation made of concrete or of some other material like stone or masonry?
  10. Does my house have vulnerable features like a chimney or porch that need to be tied to the main house?
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What to Ask on the Phone
A Few Questions to ask Your Marin County Earthquake Retrofitting Company on the Phone

The phone is a good place to start your search for earthquake retrofitting. Asking questions gives you a good feel for how the company deals with its customers. You want to choose a good company to work with in Marin County, whether in San Anselmo, San Rafael, Novato, Larkspur, Mill Valley, or Fairfax. The phone call also gives you insight into how knowledgeable the company is about earthquake retrofitting. The conversations may be long and detailed, and they may be peppered with unfamiliar terms....

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The phone is a good place to start your search for earthquake retrofitting. Asking questions gives you a good feel for how the company deals with its customers. You want to choose a good company to work with in Marin County, whether in San Anselmo, San Rafael, Novato, Larkspur, Mill Valley, or Fairfax. The phone call also gives you insight into how knowledgeable the company is about earthquake retrofitting. The conversations may be long and detailed, and they may be peppered with unfamiliar terms. To keep your balance, it can be a good idea to have a list of questions drawn up so that at the end of the calls, you can compare the companies consistently.

  1. Has your company earned and maintained a Diamond Certified rating?
  2. Are you licensed California state contractors?
  3. Have you worked on a house with my specific issues previously – on a hill, near a stream, multi-storey?
  4. How many levels of my house should have shear walls? (All, including the crawl space)
  5. Do you specialize in seismic retrofitting?
  6. My house was built in the early 2000’s. It’s already bolted to the foundation. Would you recommend additional retrofitting?
  7. Do you provide free estimates and plans?
  8. Do you work with engineers or architects?
  9. What kind of training do you do, how do you keep up with changes in the building codes?
  10. My foundation is cracked – can you still retrofit my house?
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What to Ask in Person
Ask your Marin County Earthquake Retrofitter in Person

You will probably speak with a Marin County seismic retrofitting specialist either when they come to your house to prepare an estimate, or after the estimate and plans are drawn up, to go over those plans. In either case, take your time so that you understand what is being recommended and the proposed benefit. Your house in Marin County, whether in Larkspur, Mill Valley, Marshall, Tiburon, San Anselmo, Novato, or San Rafael is an investment, and you want to keep it safe. Earthquake retrofitting can also be expensive, so you want to know what you are paying for....

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You will probably speak with a Marin County seismic retrofitting specialist either when they come to your house to prepare an estimate, or after the estimate and plans are drawn up, to go over those plans. In either case, take your time so that you understand what is being recommended and the proposed benefit. Your house in Marin County, whether in Larkspur, Mill Valley, Marshall, Tiburon, San Anselmo, Novato, or San Rafael is an investment, and you want to keep it safe. Earthquake retrofitting can also be expensive, so you want to know what you are paying for. It might make sense to draw up a list of questions so that you are sure they are covered, no matter how the conversation goes. Some questions might include:

  1. My house beams are redwood, not Douglas fir-larch. Does the recommendation account for this difference?
  2. My house already is bolted to the foundation. What will these extra bolts provide?
  3. What method of blocking, or connecting the shear wall to the mudsill, are you recommending? Nail blocking, staple blocking, reverse nail blocking, or flush-cut? And why?
  4. There is an uneven number of bolts on the different sides of my house – won’t that make the sides have a different amount of resistance?
  5. What grade of plywood are you recommending? How many plies are you recommending in the plywood?
  6. What kind of lumber are you planning to use for framing the shear wall?
  7. How closely will you be placing the nails in the shear wall plywood?
  8. What kinds of hold-downs are you recommending and are they being used as recommended by the manufacturer?
  9. Do you think the concrete is sound enough to use mechanical anchors? Or will you be using adhesive (epoxy) anchors?
  10. You’ve recommended many enhancements. Can you rank them in order of importance, with safety being my prime consideration?
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What to Ask References
Questions for References

It’s best to choose a Diamond Certified earthquake retrofitter because all certified companies have passed an in-depth ratings process that most other companies can’t pass. If you want quality from an earthquake retrofitter in Marin County and the greater Bay Area, you can have confidence choosing a Diamond Certified company. Diamond Certified reports are available online for all certified companies. And you’ll never be fooled by fake reviews....

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It’s best to choose a Diamond Certified earthquake retrofitter because all certified companies have passed an in-depth ratings process that most other companies can’t pass. If you want quality from an earthquake retrofitter in Marin County and the greater Bay Area, you can have confidence choosing a Diamond Certified company. Diamond Certified reports are available online for all certified companies. And you’ll never be fooled by fake reviews. That’s because all research is performed in live telephone interviews of actual customers.

If you can’t find a Diamond Certified earthquake retrofitter within reach, you’ll have to do some research on your own. If you do, it’s wise to call some references provided by your earthquake retrofitter. Keep in mind, though, that references provided to you by the earthquake retrofitter are not equal in value to the large random sample of customers surveyed during the Diamond Certified ratings process. That’s because references given to customers from companies are cherry-picked instead of randomly selected from all their customers. So the contractors will likely give you a few customers to call that they know are satisfied.

If you do call references on your own, specifically ask for a list of the company’s 10 most recent customers. This will help avoid them giving you the names of only customers they know were satisfied.

  1. Did the earthquake retrofitters work with engineers or architects, or did they do all the plans themselves?
  2. Did the earthquake retrofitters offer free plans and estimates?
  3. Did the earthquake retrofitters take the time to explain why a certain recommendation was made?
  4. Did you feel confident in their knowledge of current building codes and techniques for resisting earthquakes?
  5. Did your house have the same features as mine – multi-storey, on a hillside, near a stream?
  6. Have you been through an earthquake since the house was retrofit? Did you notice anything?
  7. Was the earthquake retrofitting company a good contractor – delivering estimates on time, arriving on time, working through the day, leaving a clean job site?
  8. Did you notice any problems when you inspected the work – split wood, nails sunk in too deeply so they were not flush with the surface, broken concrete, countersunk bolts and washers?
  9. If you noticed problems, did the earthquake retrofitting company address them politely and immediately?
  10. Did the earthquake retrofitting company not only help you get the building permit, but also help you with the building inspections during the progress of the job?
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Review Your Options
To Find and Hire a Good Earthquake Retrofitter in Marin County
The Diamond Certified symbol has been awarded to companies that scored Highest in Quality in an accurate ratings process.

Your choice of earthquake retrofitter … So before deciding on the best earthquake retrofitter in Marin County for you, it’s important to consider the following questions....

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Your choice of earthquake retrofitter … So before deciding on the best earthquake retrofitter in Marin County for you, it’s important to consider the following questions.

  1. Is the earthquake retrofitter committed to keeping up with the latest training and recommendations for earthquake retrofitting?
  2.  Is the earthquake retrofitter committed to using the building materials – lumber, fasteners, hold-downs – as specified in the building code, in the plans, and as specified by the manufacturer?
  3. Is the earthquake retrofitter willing to work with an engineer or architect on complex projects? And willing to admit when they need such help?
  4. Does the earthquake retrofitting company specialize in seismic retrofitting?
  5. Does the earthquake preparedness specialist have experience working with your particular type of house?
  6.  Does the earthquake retrofitter have a commitment to delivering quality work that meets or exceeds the building code standards?
  7. Does the earthquake retrofitter have the skills to work with the local housing authority to get the permit to work on the project?
  8. Is the earthquake retrofitter committed to reducing the amount of disruption the job will entail?
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How to Work With
Before you Hire a Marin County Earthquake Retrofitter

You must have a written contract in place before you hire your earthquake retrofitting company in Marin County. The contract should specify what work will be performed, the timeframe for completing the work, what the work will cost. The work and the payment may be tied together - for example, there may be certain milestones when payment is required. Make sure you know what those milestones are. The contract should also list any subcontractors....

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You must have a written contract in place before you hire your earthquake retrofitting company in Marin County. The contract should specify what work will be performed, the timeframe for completing the work, what the work will cost. The work and the payment may be tied together - for example, there may be certain milestones when payment is required. Make sure you know what those milestones are. The contract should also list any subcontractors.

Your contractor may also specify what is not included – you should check this very carefully. The contractor is required to tell you if he or she sees certain things as the work progresses – water leaks, plumbing leaks, termites, wood rot, and other conditions that may affect the work. If the contractor does not report these to you, the contractor may find himself or herself held responsible for them. Look out for exclusions of previously existing conditions that were not uncovered before work started or only uncovered while doing the work. If you change the scope of the contract to include getting these fixed – either out of necessity or because you want to – you should get a change or amendment to the contract written down. The contract may allow a contractor to stop working on the job. Typical scenarios would include stopping the job for non-payment. Make sure you understand the terms under which the contract may be terminated.

Helping Your Marin County Earthquake Retrofit Go More Smoothly
You have a role to play in making your Marin County earthquake retrofit go more smoothly. Pay attention and ask questions when the plan is presented so that you know what is going on. Try not to change the plans once the project is underway. It may happen that unforeseen circumstances force a change in the plan. Listen carefully to what your contractor is saying, especially if the contractor has mentioned a pre-existing condition. Try to determine if the pre-existing condition is something that needs to be addressed immediately or whether it can wait. Because something can come up at any time, you should always have someone who can make decisions available to respond to the earthquake retrofitting company. Don’t try to ask your earthquake retrofitter to take on more than he or she is responsible for. If plans from an engineer or architect include carport cover bracing, water heating bracing, chimney bracing, tank bracing or veneer selection, the contractor will carry these out. However, the contractor will not take responsibility for damage from the bracing. And if a contractor draws up the earthquake retrofitting plans, bracing is not part of what the contractor will cover

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Be a Good Customer
How Can You Be a Good Earthquake Retrofitting Customer?

It's the earthquake retrofitter’s responsibility put in quality earthquake retrofitting using the best possible installation techniques. But you play a big part in the success of your earthquake retrofitter, too. Here are a few simple steps you can take to be a good customer when hiring a Marin County earthquake retrofitter....

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It's the earthquake retrofitter’s responsibility put in quality earthquake retrofitting using the best possible installation techniques. But you play a big part in the success of your earthquake retrofitter, too. Here are a few simple steps you can take to be a good customer when hiring a Marin County earthquake retrofitter.

  • Be clear and upfront with the earthquake retrofitting company. Let them know what you want from your earthquake retrofitting, the long-term outcome you’re expecting and specific ways they can satisfy your expectations.
  • Remember, a friendly smile goes a long way!
  • Before you hire an earthquake retrofitting company in Marin County, restate your expectations and goals, and reiterate to the earthquake retrofitter’s representative your understanding of the agreement. Most problems with local earthquake retrofitting companies occur because of a breakdown in communication. By being clear about your expectations and theirs, you can avoid most conflicts.
  • Ask your earthquake retrofitting company if you should call to check on the progress or if he will call you with updates.
  • Be sure your service representative has a phone number where they can reach you at all times while they’re earthquake retrofitting. The work will move along more smoothly if your earthquake retrofitter can reach you for any necessary updates, questions or work authorizations.
  • When your contractor contacts you, return calls promptly to keep the earthquake retrofitting on schedule.
  • Pay for the earthquake retrofitting work promptly.

Why would you want to be a good customer? Earthquake retrofitting companies in Marin County appreciate customers who are straightforward, honest and easy to work with. Your good customer behavior sets the tone from your end and creates an environment conducive to a good relationship. Things may very well go smoother and any problems may be more easily resolved.

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Check the Work
Use Your Contract to Check Your Marin County Earthquake Retrofitter’s Work
Besides personally inspecting retrofitting work, be sure to review the written invoice. Photo: BB & B Builders Inc (2014)

The contract you sign should be a detailed and comprehensive document. It will include the scope of work, when it should be done, and when payments are expected. Whenever you reach a milestone, be sure the work is done properly before paying. Look for the proper grade and type of lumber – much lumber has stamped information on it. Look for proper installation with nails that are not embedded but are flush with the surface. Look for bolts and washers that are not countersunk – that is, the wood around them has to be gouged out so you can access them....

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The contract you sign should be a detailed and comprehensive document. It will include the scope of work, when it should be done, and when payments are expected. Whenever you reach a milestone, be sure the work is done properly before paying. Look for the proper grade and type of lumber – much lumber has stamped information on it. Look for proper installation with nails that are not embedded but are flush with the surface. Look for bolts and washers that are not countersunk – that is, the wood around them has to be gouged out so you can access them. Look for split wood or broken concrete – these should not occur. Check the installation to the best of your ability before signing off and paying.

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Written Warranties
Asking Your Marin County Earthquake Retrofitting Company for Warranties

It’s a common practice for earthquake retrofitters to give a one-year warranty on their workmanship. California state law also requires ten years for property damage due to latent defects, at least three years for property damage from poor workmanship, and four years for patent defects. The law also allows virtually an unlimited time to make claims for personal damages resulting from negligent workmanship.

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It’s a common practice for earthquake retrofitters to give a one-year warranty on their workmanship. California state law also requires ten years for property damage due to latent defects, at least three years for property damage from poor workmanship, and four years for patent defects. The law also allows virtually an unlimited time to make claims for personal damages resulting from negligent workmanship.

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Top 10 Requests
Top Service Requests

Marin County seismic retrofitters help keep houses in good shape during an earthquake. There are a few techniques that are commonly used to make houses in Marin County, whether in San Anselmo, San Rafael, Novato, Larkspur, Mill Valley, Sausalito, Fairfax or Marshall, more stiff and strong. While no one can guarantee an earthquake-proof house, there are some steps you can take.

Shear Transfer Ties
Shear transfer ties can help prevent the floor joists from sliding off the mudsill....

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Marin County seismic retrofitters help keep houses in good shape during an earthquake. There are a few techniques that are commonly used to make houses in Marin County, whether in San Anselmo, San Rafael, Novato, Larkspur, Mill Valley, Sausalito, Fairfax or Marshall, more stiff and strong. While no one can guarantee an earthquake-proof house, there are some steps you can take.

Shear Transfer Ties
Shear transfer ties can help prevent the floor joists from sliding off the mudsill.

Shear Walls
Shear walls provide stiffness and strength – both of which allow houses to better resist earthquakes. Shear walls should be installed on every level of the building, including the crawl space. Best built from plywood, the shear walls should at least be on the four exterior walls, and should be symmetrically placed. Interior shear walls are necessary when the ceiling or floor span is more than three times longer than its width and when the exterior walls don’t provide enough stiffness and strength.

New Bolts
Modern houses that don’t have a cripple wall have walls that are bolted to the foundation. Over time, these bolts may deteriorate. Bolts may also be installed in holes that are bigger than the bolt, making it possible for the earthquake to cause the bolt to shred the mudsill. Additional bolts can be added to help reinforce the original bolts.

New Foundation Anchors
Foundation anchors act like bolts, securing the mudsill, a big wood plank, to the top of the foundation, which is usually concrete or masonry. The foundation anchors can help prevent a house from sliding off its foundation.

Plans
The earthquake retrofit should be completed based on a set of plans. The plans should show what is going to be installed and where. The plans may be drawn up by a contractor, if the building can be retrofitted using prescription standards. If the building requires more particular retrofitting, the plans will be drawn up by an engineer or architect. The local housing authority determines if the building qualifies for the prescriptive standards.

Permits
All earthquake retrofitting requires a building permit. Your contractor should be able to help you apply for your permit.

Bracing
Non-structural elements in your house can benefit from bracing. Water heaters, tanks for water or propane, and similar elements may be prone to fall over in an earthquake. While you would like these secured, they do not fall under the contractor’s jurisdiction unless the contractor is working from plans drawn up by an engineer or architect who specifies the bracing. The contractor will often claim no liability for any damage resulting from the bracing.

Hold-Downs
Hold-downs are special pieces of equipment that are used to secure shear walls. While you may not ask for them by name, it’s important that they are installed according to manufacturer’s instructions. If they are contorted or improperly installed, they lose their strength. Many hold-downs are manufactured by a company named Simpson.

Moment Frames
A moment frame is a steel reinforcing structure that is used where there is not enough room for a shear wall. An engineer or architect will design the moment frame.

Foundation Work
Sometimes foundation work besides bolts and anchors is required. This may include placing columns near the walls to act as a parallel foundation system, capping existing foundations by covering the foundation wall with concrete, or replacing an existing foundation. Masonry foundations, especially unreinforced masonry foundations, are not recommended in earthquake country.

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If Things Go Wrong
The Diamond Certified Performance Guarantee

Diamond Certified earthquake retrofitting companies are backed by the Diamond Certified Performance Guarantee. If the window company is Diamond Certified and you can’t resolve the issue by talking with the owner, contact the mediation department at [email protected] or call 800-738-1138....

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Diamond Certified earthquake retrofitting companies are backed by the Diamond Certified Performance Guarantee. If the window company is Diamond Certified and you can’t resolve the issue by talking with the owner, contact the mediation department at [email protected] or call 800-738-1138.

Some Easy Ways To End Conflict with Marin County Earthquake Retrofitting Companies
Use a good contract to help prevent disputes. Sometimes, however, you run into problems. First, try to resolve the problem with your earthquake retrofitting specialist. If you cannot, you can complain about the firm to the Better Business Bureau. You can also file a complaint with the California Contractors State License Board (CSLB). The CSLB will issue citations and fines, and may force a company to complete a job or pay someone to finish a job. However, if you are looking mainly to get money or other restitution, the CSLB recommends small claims court.

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Glossary of Terms
Glossary of Terms Used By Local Earthquake Retrofitting Contractors
Residential earthquake retrofitting and seismic preparation services.
Lower story ceiling bracing helps stabilize a second story during earthquakes. Photo: John M. Jameson Construction, Inc. (2012)

The work of earthquake retrofitting is the world of construction contractors, and not all the words may be familiar to lay people. The glossary below should help you better understand all the terms being thrown about when planning and carrying out your earthquake preparations.

acceleration
Refers to a change in velocity. Earthquakes can change their velocity as the waves travel through the ground.

adhesive anchor
A bolt, or rod, along with the washer and nut that uses a chemical to adhere to the concrete of a foundation....

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The work of earthquake retrofitting is the world of construction contractors, and not all the words may be familiar to lay people. The glossary below should help you better understand all the terms being thrown about when planning and carrying out your earthquake preparations.

acceleration
Refers to a change in velocity. Earthquakes can change their velocity as the waves travel through the ground.

adhesive anchor
A bolt, or rod, along with the washer and nut that uses a chemical to adhere to the concrete of a foundation.

Also known as: epoxy anchor

anchor tie or bolt
A bolt, or threaded rod, that is used to connect the walls to the floor or roof.

bearing wall
A wall that can support vertical loads.

Also known as: load-bearing wall

connector
A connector is a steel device that holds the pieces of the house frame together. The connector is placed where two pieces of the house frame meet.

crawl space
The crawl space is an area that sits under the house. It has short wood-framed walls that are called pony walls or cripple walls.

cripple walls
A cripple wall is a short wall that sits between the foundation and the first floor. The cripple wall should go around the house's perimeter. The cripple wall sits on top of the foundation. They can be quite high when a house is built on a hillside, but are usually 12- 30 inches. They are very vulnerable to earthquakes.

diaphragm
A roof, floor, or continuous membrane that allows the earthquake forces to be transferred to the shear walls.

earthquake
A motion or vibration in the earth that occurs when the lithosphere releases energy.

Also known as: earthquake preparedness, earthquake preparation

expansion anchor
An expansion anchor is a bolt that is set into a pre-drilled hole, after which its base expands to wedge itself into the concrete. The washer and nut are also part of the assembly.

Also known as: mechanical anchor

fasteners
Fasteners may be nails, bolts, screws, or other devices used to connect framing materials.

floor girder
A beam used for floor joist support.

foundation
The foundation is the wall or slab that a house is placed on. It may be concrete, masonry, stone, etc. Concrete is best for resisting earthquakes.

holddown
A device used to prevent a wall from being lifted up. It is placed at the ends of the shear wall framing.

Also known as: hold-down

joist
A joist is part of a floor system. These wooden pieces sit under the floor boards and support the floor. A rim joist goes along the perimeter of the floor.

lateral forces
Lateral forces are effects from earthquakes that move the house from side to side.

Also known as: horizontal forces

load
A load is the weight of material that has to be supported.

moment-resisting frame
A steel device or frame used to resist lateral forces by improving the joint connection between column and beams.

Also known as: moment frame

mudsill
The mudsill is a wooden plank that sits on top of the foundation. The floor system is attached to the mudsill.

Also known as: wood sill, sill plate

OSB/plywood sheathing
The material used to create the shear wall - OSB is fiber-based material, and plywood is wood-based.

perimeter
The outer sides of the building

pier
A column made of concrete or masonry that supports a beam.

post
A piece of wood deployed vertically to support a load.

rafter
Beams or other devices used to support the roof.

seismic retrofit
Measures taken to improve the building's ability to withstand an earthquake. Especially includes structural stability improvements.

shear stress
Shear stress is a physics concept that says that forces act on a body in opposite directions, but not in the same line. Shear stress will often cause a diagonal or X-shaped crack.

stiffness
Refers to the ability of a structural element or system to resist being deformed.

strength
Refers to the ability to resist the forces applied.

stud
The vertical pieces of the structure forming the walls.

Also known as: framing

unreinforced masonry
Masonry that uses mortar as a bonding agent and combines that with the weight of the masonry material to provide the structural stability. It is not allowed in California because it does poorly in earthquakes. Reinforced masonry has steel added to provide better structural stability.

Also known as: URM

vertical
Refers to something that is perpendicular to the ground.

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Frequently Asked Questions
FAQ for Earthquake Retrofitting Services

Q: Why choose a Diamond Certified earthquake retrofitting company? ...

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Q: Why choose a Diamond Certified earthquake retrofitting company?
A: Diamond Certified helps you choose an earthquake retrofitting company with confidence by offering a list of top-rated local companies who have passed the country's most in-depth rating process. Only earthquake retrofitting companies rated Highest in Quality earn the prestigious Diamond Certified award. Most companies can't pass the ratings. American Ratings Corporation also monitors every Diamond Certified company with ongoing research and ratings. And your purchase is backed by the Diamond Certified Performance Guarantee. So you'll feel confident choosing a Diamond Certified earthquake retrofitting company.

Q: My house has withstood many minor quakes. Do I really need earthquake retrofitting services?
A: It's a good idea to at least check into retrofitting. The Bay Area is home to several faults, and the closer your house is to a fault, the more damage is likely. In addition, over time, your house could be subject to changes - bolts could rust, water could seep into unexpected places, concrete can get old and less reliable. Earthquake retrofitting by definition should never harm an existing structure - it should only improve its ability to withstand earthquakes.

Q: How much does earthquake retrofitting cost?
A: It's impossible to say how much your retrofit will cost. It depends on your house, the kind of foundation it sits on, whether you are on a hillside or not, how many levels the house has, whether there are huge openings that need extra support, and the like. Some firms quote that a very basic retrofit will cost between four and seven thousand dollars, but this is a very hard figure to rely on. The best thing is to find a company that will give you a free estimate.

Q: If I retrofit my house, I am good to go for any earthquakes?
A: An earthquake retrofit does not make a house earthquake-proof. Nothing can. You should avoid firms that promise to make a house earthquake proof. An earthquake retrofit is designed to make your house better withstand an earthquake without significant damage. It is an investment to avert risk, not a sure thing.

Q: Do I need an engineer or architect to draw up my earthquake retrofit plans?
A: It depends. If you have a fairly straightforward house with no tricky bits, a contractor should be able to draw up plans that follow the prescriptive standard. However, for anything beyond the basic, an architect or engineer should draw up the plans. The local housing authority granting the permit to build will be the one who decides if the house fits the criteria to use the prescriptive standard.

Q: Do I need a permit to retrofit my house for earthquakes?
A: Yes, you need a permit to retrofit your house. Some of the work will be done on the foundation, which needs a permit. Your shear wall also requires a building permit. Your contractor should be able to help you get the required permit. Some cities and areas in the Bay Area will waive permit fees for retrofits, so you should ask about the fees required.

Q: What do you mean there is no retrofit building code?
A: According to the California Earthquake Authority, California has a seismic retrofit code, but it is not mandatory. The code is also limited to addressing simple houses built on flat lands. However, there are building codes, which change frequently. Many building code changes have been made after the Loma Prieta and Northridge quakes. For example, after the Northridge quakes, square washers are required for bolts, since the round ones tended to fail. Your contractor/engineer/architect should be up-to-date on the most recent building codes and apply them.

Q: My foundation is damaged. Can I still have earthquake retrofitting services performed?
A: Typically, if the foundation has a crack that measures less than one-eighth of an inch and does not go all the way through - you cannot see to the other side, it's ok to retrofit the foundation, according to the Association of Bay Area Government's guidelines. Cracks larger than that and other damage may require the foundation to be replaced before the retrofitting is done.

Q: Does my new home really need earthquake retrofitting?
A: Homes built recently will be fine, if the home was built to code, since the current codes include the most recent additions to preventing earthquake damage. However, you should check that the seismic provisions of the code were followed correctly. Sometimes they are skipped or incorrectly completed because they increase the cost of construction, and the contractor may not have known how to perform them. Plywood nailing is especially important to the stiffness and strength of house and is one of the areas that may not have been correctly implemented. If retrofitting is required on a new house, it is usually fairly simple.

Q: Does earthquake retrofitting really work?
A: As mentioned, earthquake retrofitting is a preventive measure, not a guarantee. However, the industry is very fond of the following story. In Santa Cruz, two houses were built about 100 years before the 1989 earthquake. They were built by the same builder with identical construction techniques and materials. Over the years, both houses had been remodeled several times. In 1984, a developer bought both houses. One, he had time to retrofit with shear walls on the cripple walls and by securing the mudsill to the foundation. The other house, he did not have time to retrofit before the 1989 quake. After the quake, the retrofitted house, 210 Elm Street, required $5,000 to repair. The house that had not been retrofitted, 214 Elm Street, broke into four pieces. It took over a quarter of a million dollars to repair 214 Elm St.

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Consumer Agencies
Consumer Agencies and Associations for Earthquake Retrofitting Contracting Companies

Association of Bay Area Governments (ABAG) (www.abag.ca.gov/)
California Earthquake Authority (CEA) (www.earthquakeauthority.com/)
California Emergency Management Agency (CALEMA) (www.calema.ca.gov/)
Contractors State License Board (CSLB) (www.cslb.ca.gov/)
Department of Conservation (www.conservation.ca.gov/)...

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Association of Bay Area Governments (ABAG) (www.abag.ca.gov/)
California Earthquake Authority (CEA) (www.earthquakeauthority.com/)
California Emergency Management Agency (CALEMA) (www.calema.ca.gov/)
Contractors State License Board (CSLB) (www.cslb.ca.gov/)
Department of Conservation (www.conservation.ca.gov/)
Federal Emergency Management Agency (FEMA) (www.fema.gov/)

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Industry Information
Marin County Earthquake Retrofitting Information
Popular Types of Earthquake RetrofittingEarthquake Retrofitting Services Available in Marin County Cities Served Zip Codes Served
storefront seismic retrofittingfoundation holdown bracket installationAlmonte
Bel Marin Keys
Belvedere
Belvedere Tiburon
Black Point
Bolinas
Corte Madera
Dillon Beach
Dogtown
Fairfax
Forest Knolls
Greenbrae
Ignacio
Inverness
Kent Woodlands
Kentfield
Lagunitas
Larkspur
Lucas Valley
Marin City
Marinwood
Marshall
Mill Valley
Mission Rafael
Muir Beach
Muir Woods
Nicasio
Novato
Olema
Point Reyes Station
Ross
San Anselmo
San Geronimo
San Marin
San Quentin
San Rafael
Santa Venetia
Sausalito
Sleepy Hollow
Stinson Beach
Strawberry Point
Tamal
Tamalpais Valley
Terra Linda
Tiburon
Tomales
Woodacre
94901
94903
94904
94912
94913
94914
94915
94920
94924
94925
94929
94930
94933
94937
94938
94939
94940
94941
94942
94945
94946
94947
94948
94949
94950
94956
94957
94960
94963
94964
94965
94966
94970
94971
94973
94974
94976
94977
94978
94979
slab foundation retrofittingsoft story seismic retrofitting
pier and beam foundation retrofittingfoundation repair
block foundation retrofitsgirder securing
concrete building reinforcementbuilding earthquake proofing
residential seismic retrofittingstructural engineering services
commercial seismic retrofittingstructural seismic designs
industrial earthquake retrofittingearthquake resistant building services
apartment earthquake retrofittingseismic retrofitting
bridge seismic retrofitsfoundation retrofits
 foundation bolting
 cripple wall bracing