Frequently Asked Questions

·         Why Consider Avant-Garde Construction Enterprise?
Avant-Garde Construction Enterprise is fully licensed, insured, and bonded. Matthew Gatterman is a second-generation San Francisco Bay Area seismic retrofit contractor and has spent his entire life involved with seismic retrofit, drainage, and foundation projects in the Bay Area (his father started specializing in seismic retrofits in 1992 after spending 20 years as a new-construction development contractor across three different states).

From “crawl space only retrofits” of flat-lot homes to complete foundation replacements to “entire building retrofits of”: five-story steep hillside homes, apartment complexes, beach-front properties, and even complex cantilevered cliff-side homes, we have done it all (including retrofitting hundreds of “retrofitted” homes that were done incorrectly). It is rare to find anyone as experienced.

We provide detailed proposals, professional site visits, and have excellent 5-star reviews from local clients. We treat every home like it is our own.

• What is seismic retrofitting?
  Seismic retrofitting is the process of modifying an existing structure to make it more resistant to earthquakes. This typically involves reinforcing the foundation, cripple walls, and connections between structural elements to create a continuous load path.

• Why is seismic retrofitting important in the Bay Area?
  The USGS estimates a 72% chance of a major earthquake (6.7 or greater) in the Bay Area within the next 18 years. Many homes lack proper reinforcement, putting them at risk for significant damage.

• What does a retrofit consultation include?
  Our consultations include a thorough site assessment, professional photographs, detailed notes and drawings, and itemized recommendations. You’ll receive a to-scale drawing of your home and a comprehensive proposal.

• Do you offer free estimates?
  We provide free preliminary estimates via email if you share your address, photos, and project details. Please note, site visit clients are prioritized for scheduling and proposals. Please schedule a site visit to guarantee service. For a detailed, written proposal and site visit, there is a fee based on your location.

• What types of projects do you handle?
  We specialize in:
  Earthquake Brace + Bolt (EBB) & ESS retrofits
  Crawl space & soft-story retrofits
  Foundation repair/replacement
  French drains & sump pumps/ dry-wells
  Moment frames, columns, and structural steel
  Learn more about our services
• What are the Earthquake Brace + Bolt (EBB) & Earthquake Soft-Story (ESS) programs?
  The EBB & ESS programs offer state-sponsored grants that help homeowners pay for seismic retrofits. Learn more here.

• What is the difference between a “soft-story” and a “crawl space” retrofit?
  A soft-story retrofit strengthens buildings with large openings (like garages) on the ground floor. A crawl space retrofit focuses on reinforcing the foundation and short walls beneath the main floor.

·         What is foundation repair/ replacement?
Foundation repair/replacement refers to the process of fixing or completely rebuilding the base structure that supports your home. The foundation is critical for the stability and safety of your house, especially in earthquake-prone areas like the Bay Area.

Foundation Repair
-Involves fixing specific issues such as cracks, settling, water damage, or weakened sections.
-Common repairs include epoxy injection for cracks, adding new footings, underpinning (strengthening the foundation with piers or supports), and sealing against moisture.
-The goal is to restore the foundation’s strength and prevent further damage.

Foundation Replacement
-Required when the existing foundation is too damaged or deteriorated to repair.
-The process involves temporarily supporting the house, removing the old foundation, and pouring a new concrete foundation.
-This is a major construction project but provides a long-term solution and brings your home up to current building codes.

Foundation repair or replacement ensures your home remains safe, level, and structurally sound—protecting it from earthquakes and other hazards.

·         What are French Drains, Sump-Pumps, and Dry-Wells?
A French drain is a trench lined with filtration fabric then filled with ¾” drainage rock, and contains a perforated pipe that redirects surface water and groundwater away from your home’s foundation or crawl space– to help prevent water from pooling around your foundation, which can cause damage or flooding. French Drains are commonly installed along the perimeter of a home or in areas with poor drainage.

A sump pump is a mechanical device installed in a pit (sump basin) that ejects subterranean water away from your home, usually to a storm drain or dry-well. Sump-pumps are essential for homes with water intrusion issues or high groundwater tables that cannot use gravity for ejection lines to the street gutter.

A dry-well is an underground structure that collects and disperses water from sources like French Drains or sump pumps. Dry-wells allow water to slowly percolate into the surrounding soil, reducing surface runoff and preventing flooding. They are often used in conjunction with French drains and sump pumps for comprehensive drainage solutions.

In summary, French Drains, sump pumps, and dry-wells work together to keep your foundation dry and protected from water damage.

·         What are moment frames, columns, and structural steel?

A moment frame is a steel frame designed to resist lateral (sideways) forces—like those from earthquakes—while allowing for large openings (such as garage doors) in a building’s wall. Consists of vertical steel columns and horizontal steel beams, rigidly connected. Used in “soft-story” retrofits to strengthen weak ground floors without closing off open spaces. Helps prevent collapse by absorbing and transferring earthquake forces.

A moment column is a vertical structural element that supports the weight of the building above it. In seismic retrofits, steel columns are often added to reinforce areas with large openings or weak points. Columns work with beams and moment frames to provide strength and stability.

Structural steel refers to steel components (beams, columns, frames, etc.) used to reinforce or build parts of a structure. Provides exceptional strength and flexibility, making it ideal for earthquake resistance. Used in retrofits to support sagging floors, brace cripple walls, or create moment frames.

To summarize, moment frames, columns, and structural steel are essential tools in seismic retrofitting—especially for homes or buildings with large openings or unique layouts. They provide the strength and flexibility needed to keep structures safe during earthquakes.

• What materials do you use?
  We use structural steel, plywood, engineered lumber, structural screws, and specialized seismic connectors (brackets, plates, bolts, hold-downs, etc.), all installed to meet or exceed building codes.

• Do I need engineered plans?
  You may need engineered plans for complex projects (e.g., 3+ stories, tall cripple walls, or soft-story retrofits). We can recommend experienced engineers if needed.

·         Are there rebates or incentives?
Yes! The EBB and ESS programs offer grants for qualifying retrofits. We also offer referral rebates—$100 for each successful referral.

• How long does a typical seismic retrofit take?
  Most standard retrofits are completed in 1–3 days, depending on the size and complexity of the project. Advanced projects may take weeks or months– complete foundation replacements, entire-home-retrofits of complex hill-side homes, etc.

• Will I need to move out during the retrofit?
  In most cases, you can remain in your home during the retrofit. Work is typically done in the crawl space or garage, minimizing disruption. When work is done in your living space, we will use floor protection and plastic to section-off work areas and protect your home.

• What is a cripple wall, and why is it important?
  A cripple wall is the short wall between your home’s foundation and the first floor. It’s often the weakest part of older homes and a common failure point during earthquakes. Reinforcing cripple walls by creating shear walls is a key part of retrofitting.
• What is a shear wall?
  A shear wall is a structural wall designed to resist lateral (sideways) forces caused by wind or earthquakes. In residential seismic retrofits, shear walls are typically made by attaching plywood panels to the inside of the stud-framed walls in the crawl space or garage.

Key points about shear walls:
-They help prevent your home from swaying or collapsing during an earthquake.
-Shear walls transfer horizontal forces from the roof and floors down to the foundation.
-In retrofits, they are often combined with seismic connectors, anchor bolts, and hold-downs for maximum strength.
-Shear walls are a critical part of creating a “continuous load path” in your home’s structure.

• What is a “continuous load path” and why does it matter?
  A continuous load path connects all parts of your home—roof, walls, floors, and foundation—so earthquake forces are safely transferred down to the ground. This prevents structural failure during a quake.
• What kind of hardware do you use?
  We use premium seismic hardware such as structural screws, seismic connectors, anchor bolts, and hold-downs—often exceeding minimum code requirements for added safety.
• What is a structural screw?
  A structural screw is a heavy-duty, high-strength screw specifically designed for use in construction and structural applications, including seismic retrofits.
  
  Key facts about structural screws:
  -They are engineered to provide superior holding power and load capacity compared to standard wood screws or nails.
  -Structural screws are often used to attach framing members, or secure hardware like seismic connectors and hold-downs.
  -They have special threads and hardened steel for strength, and many are coated for corrosion resistance.
  -Unlike nails, structural screws are less likely to split old or dry lumber and have a higher withdrawal resistance, making them ideal for retrofitting older homes.
  -Structural screws are a modern, reliable fastener that helps ensure strong, lasting connections in seismic retrofits and other structural work.

• What is a seismic connector?
  A seismic connector is a specialized piece of hardware used to strengthen the connections between different parts of a building’s structure, helping the home move as a single unit during an earthquake.

Key facts about seismic connectors:
-They include brackets, plates, straps, angles, and ties made of steel.
-Common types are foundation plates, L-shaped framing angles, hurricane ties, and framing clips.
-Seismic connectors are installed at critical joints—such as where the framing meets the foundation, or where walls meet floors and roofs.
-Their main job is to prevent parts of the house from pulling apart or shifting during seismic activity.
-By tying the structure together, seismic connectors help create a continuous load path, which is essential for effective earthquake resistance.

·         What is an anchor bolt?
An anchor bolt is a heavy-duty fastener used to securely connect a building’s wood framing (usually the mudsill) to its concrete foundation.

Key facts about anchor bolts:
-They are typically made of steel and embedded into the concrete foundation.
-The top of the bolt sticks up through the mudsill, where it’s fastened with a nut and steel bearing plate.
-Anchor bolts help prevent the house from sliding off its foundation during an earthquake.
-They are a critical part of seismic retrofits, especially in older homes that may lack proper bolting.
-Properly installed anchor bolts are essential for keeping your home anchored and safe during seismic events.

·         What is a hold-down?
A hold-down is a heavy-duty steel bracket used in seismic retrofits to anchor the ends of shear walls or other structural elements to the foundation.

Key facts about hold-downs:
-They are installed at the ends of shear walls or critical framing points.
-Hold-downs are bolted to the concrete foundation and attached to the wood framing with large screws or bolts.
-Their main purpose is to resist “uplift” and “overturning” forces during an earthquake, preventing the wall from rocking or pulling away from the foundation.
-Hold-downs work together with anchor bolts and shear panels to create a strong, continuous load path.

In summary, hold-downs are essential for keeping your home’s walls securely anchored to the foundation during seismic activity.

·         What is a plywood panel?
A plywood panel is a flat sheet made from thin layers (plies) of wood veneer that are glued together, with the grain of each layer running perpendicular to the previous one. This construction gives plywood its strength and stability.

In seismic retrofits:
-Plywood panels are attached to the framing of cripple walls or other structural elements to create shear walls.
-They help resist lateral (sideways) forces during an earthquake, preventing the walls from collapsing or shifting.
-Plywood is preferred because it is strong, durable, and easy to work with.

Plywood panels are a key material in seismic retrofits, used to reinforce walls and improve your home’s earthquake resistance.

• How do I know if my home needs a seismic retrofit?
  If your home was built before the 1980s, has a raised foundation, or has a crawl space or soft-story (living space over a garage), it likely needs a retrofit. We can assess your home and provide recommendations.
• What if my home already had some retrofit work done?
  We’re happy to review previous work! Please email us photos and any available plans, and we’ll provide recommendations for any additional improvements as soon as we can.
  Please note, site visit clients are prioritized for scheduling and proposals. Please schedule a site visit to guarantee service.

·         Can I get a discount if my neighbor also retrofits their home?
Yes! If you and a neighbor schedule retrofits on consecutive days, both of you can receive a credit. We also offer rebates for successful referrals.

·         How soon will I get my proposal after a site visit?
In most cases, you’ll receive a detailed, itemized proposal within 2–5 business days after your site visit. Timing will be communicated when scheduling.

• Can I get a preliminary estimate without a site visit?
  Yes! If you provide your address, contact info, and some photos or details about your home, we can send a free preliminary estimate by email. Please note, site visit clients are prioritized for scheduling and proposals.
  Please schedule a site visit to guarantee service.

• What if my crawl space or foundation is hard to access?
  Most contractors simply skip these areas. We’re experienced with challenging access situations and ensure your seismic retrofit is done properly– no matter what.

·         Do you work with engineered plans?
Yes! If you already have engineered plans, please email them to sales@avant-gardece.com. We’ll review them and provide a proposal as soon as we can.
Please note, site visit clients are prioritized for scheduling and proposals. Please schedule a site visit to guarantee service.

• Are your crews licensed and insured?
  Yes, Avant-Garde Construction is fully licensed, bonded, and insured for all work performed.
• Do you handle permits?
  Yes, we can assist with the permitting process and ensure all work meets local building codes.

• What happens if you find additional issues during the retrofit?
  There will not be any issues discovered in any areas that were visible during the site visit. We conduct thorough site visits to avoid this possibility. If we discover unexpected conditions that were covered up by existing plywood, stucco, and/ or drywall during the site visit (like dry rot or termite damage), we’ll document them with photos and discuss repair options before proceeding.

• Do you offer financing?
  We do not offer in-house financing, but we do provide financing through Acorn. You can check offers here:
  https://www.acornfinance.com/pre-qualify/?d=TCLDX&utm_medium=web_pre_qual_banner
  Many clients also use home equity loans or lines of credit. Additionally, some government programs may offer grants or low-interest loans for seismic upgrades.

·         What areas do you serve?
Day-to-day, we serve the entire Greater San Francisco Bay Area. If you’re outside this area, we can still accommodate– let us know and we’ll advise on next steps.

• Can seismic retrofitting increase my home’s resale value?
  A properly retrofitted home is often more attractive to buyers and may increase your property value, especially in earthquake-prone areas.

• Will seismic retrofitting lower my homeowner’s insurance premium?
  Many insurance companies offer discounts for homes that have been professionally retrofitted.
• Can you help with insurance documentation?
  Yes! After your retrofit, we will provide documentation and photos for your insurance company, which may help you qualify for discounts.

·         Do you provide warranties on your work?
Yes, Avant-Garde Construction provides warranties on workmanship and materials. Details will be included in your proposal.

·         What if my home is a historic property?
We have experience working with historic homes and can recommend retrofit solutions that preserve your home’s character while improving safety.

·         Can you work with my contractor or architect?
Absolutely! We’re happy to collaborate with your existing team to ensure your retrofit integrates smoothly with other renovations or repairs.

·         What payment methods do you accept?
We accept checks, credit cards, and electronic payments such as Zelle. Payment details will be outlined in your proposal.

·         How do I schedule a consultation?
You can book a consultation directly through our online booking system, email, or phone.

• Can you retrofit homes with brick or stone foundations?
  Retrofits for brick or stone foundations are more complex and may require engineered solutions. We can assess your home and recommend the best approach.

·         What is the average cost of crawl space retrofits in the Bay Area?
The average cost for a minimum-requirement crawl space seismic retrofit in the Bay Area can range anywhere from $4,000-$40,000+ for most single-family homes. The final price depends on factors like:
-The size and layout of your home
-The condition and accessibility of the crawl space
-Whether engineered plans are required
-The extent of reinforcement needed (cripple wall bracing, bolting, shear panels, etc.)
-Any additional repairs (dry rot, termite damage, etc.)

For a more accurate estimate, we recommend a site visit, which includes a detailed assessment, professional photos, and a written proposal.

·         How do I prepare my home for a retrofit project?
Clear access to the crawl space, garage, or basement is helpful. Move personal items away from work areas and let us know about any pets or special concerns.

·         What should I consider when planning earthquake retrofits for my home?
When planning earthquake retrofits for your home, consider the following key factors:

1. Home Age & Construction Type:
Older homes (especially pre-1980s) and those with raised foundations, crawl spaces, or soft-story designs are often most vulnerable.

2. Vulnerable Areas:
Identify weak points such as cripple walls, unbolted mudsills, large openings (garages), and unreinforced foundations.

3. Building Codes & Local Regulations:
Make sure your retrofit plan complies with local building codes and any city-specific requirements (like San Francisco’s soft-story ordinance).

4. Engineering Needs:
Some homes require engineered plans, especially if they have complex layouts, multiple stories, or unique conditions.

5. Qualified Contractor:
Choose a contractor with extensive seismic retrofit experience and strong local knowledge—like Avant-Garde Construction.

6. Budget & Financing:
Costs can vary widely. Consider your budget, available rebates (like EBB/ESS), and possible insurance discounts.

7. Permit Process:
Most retrofits require permits. A reputable contractor will help with permitting and inspections.

8. Disruption & Access:
Plan for access to crawl spaces, garages, or basements. Most retrofits allow you to stay in your home.

9. Documentation:
Keep records of all work, permits, and photos for insurance and resale purposes.

10. Future Value:
A retrofit not only protects your family but can also increase your home’s value and marketability.

• What sets Avant-Garde apart from other contractors?
  We go beyond minimum code requirements, providing comprehensive assessments, detailed proposals, and premium hardware. Our team has completed over 3,000 retrofits and is highly rated by clients.

·         What are the best options for seismic retrofits in the San Francisco Bay Area?
Great question! The best options for seismic retrofits in the San Francisco Bay Area depend on your home’s structure, age, and specific vulnerabilities. Here are the most effective and commonly recommended retrofit solutions:

Top Seismic Retrofit Options for Bay Area Homes

1. Crawl Space Retrofits

• Bolting the mudsill (the wood framing at the base of your home) to the concrete foundation.
• Installing seismic connectors to attach the floor framing to the mudsill / cripple walls. When you have cripple walls, these attach the top of the walls to the floor framing. When you do not have cripple walls, these attach the mudsill directly to the floor framing.
• Adding plywood shear panels to cripple walls for lateral strength.
• Installing hold-downs for uplift and overturning protection.

2. Soft-Story Retrofits

• Installing steel moment frames or proprietary shear walls in buildings with large garage openings or open ground floors.
• Reinforcing columns and beams to prevent collapse during an earthquake.

3. Earthquake Brace + Bolt (EBB) Retrofits

• Standardized retrofit for older homes, involving foundation bolting and bracing cripple walls.
• Qualify for state grants.

4. Foundation Repair or Replacement

• Replacing or repairing damaged, cracked, or unreinforced foundations.
• Upgrading to meet current seismic codes.

5. Structural Steel Upgrades

• Adding steel beams, columns, or moment frames for additional strength, especially in multi-story or complex buildings.

6. Engineered Solutions

• Custom retrofits designed by a structural engineer for unique or complex homes, including hillside properties or those with irregular layouts.

Bonus:

• Always use code-compliant, high-quality hardware (like Simpson Strong-Tie products).
• Work with experienced local contractors familiar with Bay Area building codes and soil conditions.
• Are there specific regulations for soft-story retrofits in the San Francisco area?
  Yes, there are specific regulations for soft-story retrofits in the San Francisco area.
  San Francisco has a Mandatory Soft-Story Retrofit Program that requires certain multi-unit, wood-frame buildings with a “soft-story” condition (typically, buildings with large openings like garages on the ground floor and residential units above) to be seismically strengthened. This ordinance applies to buildings built before 1978 with five or more residential units and at least two stories over a “soft” or open front.
  
  Key points:
  The city requires engineering plans and permits for soft-story retrofits.
  The work must comply with local building codes and standards, often exceeding minimum state requirements.
  Deadlines for compliance were set in phases, but enforcement continues for buildings not yet retrofitted.
  Retrofit solutions often include installing steel moment frames, shear walls, and foundation upgrades.
  For more details, you can visit the San Francisco Department of Building Inspection’s Soft-Story Retrofit Program page.
  
  

·         How can I find a reliable contractor for foundation replacement in Greater San Francisco?
Finding a reliable contractor for foundation replacement in the Greater San Francisco Bay Area is crucial for your home’s safety and investment.

Here are some steps and tips to help you choose wisely:

-Check Licensing & Insurance
-Ensure the contractor is licensed, bonded, and insured in California (check at CSLB).
-Look for Experience
-Choose contractors with extensive experience in foundation work and seismic retrofits, especially in Bay Area soil and building conditions.
-Read Reviews & Ask for References
-Check Yelp, Google, and the Better Business Bureau for reviews.
-Ask the contractor for references from prior foundation projects.
-Verify Specialization
-Make sure they specialize in foundation replacement and not just general construction.
-Request Detailed Proposals
-Get a written, itemized proposal outlining scope, materials, timeline, and costs.
-Ask About Permits & Inspections
-A reputable contractor will handle permits and schedule inspections as required by your city or county.
-Evaluate Communication
-Choose a contractor who is responsive, answers your questions clearly, and provides thorough explanations.
-Compare Multiple Bids
-Don’t just go with the lowest price—compare experience, quality, and thoroughness.