Seismic Truth Audits™: What We Keep Finding Under “Retrofitted” Bay Area Homes

On paper, many Bay Area homes look “safe”:

• EBB retrofit “completed”
• Permit finaled
• Photos uploaded
• Box checked: “meets Plan Set A”

But when we crawl under those same homes for a Seismic Truth Audit™, we keep finding the same thing:

The paperwork might look good.
The retrofit does not.

This article walks through what a Seismic Truth Audit™ is, and what we actually keep finding under homes that were already “retrofitted.”

 

What is a Seismic Truth Audit™?

A Seismic Truth Audit™ is a paid, diagnostic visit for homes that:

• Have already had “seismic retrofits” done (often through EBB or past contractors), and
• Where the owner wants to know how good the work really is.

On a Truth Audit, we:

• Crawl the entire accessible area
• Map your crawl space, cripple walls, beams, and foundation
• Photograph and label all existing hardware and framing details
• Compare what we see to:
  • Plans and permits (if available)
  • Plan Set A, Chapter A3, FEMA P‑1100, etc.
  • Simpson Strong‑Tie requirements
• Identify:
  • Missing or undersized hardware
  • Wrong fasteners
  • Short or improperly embedded anchors
  • Poor or missing blocking
  • Corrosion and water issues
• Provide:
  • A to‑scale drawing of the crawl‑space support system
  • A labeled photo set you keep
  • A written findings report in plain language
  • A prioritized correction and upgrade plan, with itemized pricing if you’d like us to do the work

It’s not a sales pitch. It’s a reality check.

You can learn more here:
https://www.avant-gardece.com/seismic-truth-audits/

 

Case 1: The EBB “completed” job that wasn’t

On paper:

• Home enrolled in Earthquake Brace + Bolt (EBB)
• Plan Set A retrofit “completed”
• Permit closed
• EBB photos accepted

Under the home (what we found):

• Anchors (URFPs / bolts):
  • Right number per wall line (simply according to the table), but:
    • Many too far from corners and splices
    • Not at all required spacing
    • Some installed into weak, deteriorated concrete without correction
  • Short anchors that did not provide a full 4″ embedment once URFP thickness was subtracted
• Clips (L‑angles):
  • Quantity met the table (at first glance by an inspector), but:
    • Clips were clustered in the middle of walls, nor evenly distributed
    • Smaller, weaker L‑angles (e.g., L70) used where L90s were required
• Plywood & framing:
  • Plywood present, but:
    • Missing blocking at panel edges and around vents
    • Nails over‑driven or missing in key spots
    • No real attention paid to load path continuity

What this means in a quake:

• The floor system and cripple walls may still rack, twist, or slide more than the owner thinks.
• Failure may shift to the next weak link: poorly supported panel edges, short anchors, or unbraced corners.

What we recommended and did:

• Added anchors at corners, splices, required spacing, and first/last bays
• Upgraded under‑sized hardware to proper models
• Installed missing blocking and corrected nailing where deficient
• Documented all corrections with updated photos and a new drawing

The owner went from “we assumed we were fine” to “now we know what’s actually under our home.”

 

Case 2: “Retrofit” that ignored the floor‑to‑wall connection

On paper:

• Prior contractor claimed to have done a “full seismic retrofit”
• Plenty of photos of new plywood on cripple walls
• No detailed drawings or as‑builts

Under the home:

• Plywood shear panels on cripple walls looked okay at first glance
• But:
  • Very few connectors between the floor joists / rim joist and the cripple walls
  • No blocking/ nailing around vent notches and other panel edges
  • Plywood nailed to cripple studs, but no clear path from floor → wall → foundation

In simple terms:

• The walls were braced
• The floor system was not well tied to those walls

It’s like strengthening the legs of a table without properly fastening the tabletop. The table can still slide or rack.

Our corrections:

• Added the correct Simpson L90 / H10 connectors between joists, rim, and cripple walls
• Installed roll‑over blocks to keep joists from twisting and disengaging
• Brought the load path closer to what Plan Set A expects, not just “plywood on walls”

The owner had paid for “a retrofit.” What they really had was half a load path. The Truth Audit revealed that; the correction finished it.

 

Case 3: Crawl‑space retrofit done; soft‑story untouched

On paper:

• Crawl‑space seismic work done years ago
• EBB participation
• The owner assumed the whole home was now “earthquake safe”

Reality:

• Crawl‑space had basic Plan Set A work
• But the home had living space over a large garage opening – a classic soft‑story
• No seismic work whatsoever had been done at the garage level:
  • No braced frames
  • No hold‑downs
  • No collectors

In a significant earthquake, the highest risk for that home was:

• The garage level
• Not the crawl space

That’s exactly what we see over and over:

Program work focuses on what’s easy to standardize (crawl spaces).
The biggest risk (soft‑story) is left alone.

What we did:

• Performed a full Seismic Truth Audit™ of the existing crawl‑space work
• Evaluated the garage level using FEMA P‑1100‑2B as a guide
• Proposed a combined solution:
  • Fix and upgrade the weak points in the crawl space
  • Design and install a proper soft‑story retrofit (using FEMA P-1100-2B)
  • Tie everything into one coherent load path

The owner learned that “a retrofit” is not a single checkbox – it’s a system.

 

Common patterns we keep seeing

Across dozens of Truth Audits, the same themes repeat:

1. Right counts, wrong parts.
   • Tables say “X clips per wall line” – contractors hit the number, but:
     • Use smaller, weaker clips
     • Put them in the wrong locations
2. Short anchors / poor embedment.
   • 4″ Titen HDs or short wedge anchors used through plates/brackets that don’t leave a full 4″ in solid concrete.
   • Technically meeting a “4″ length” but not the intent of 4″ embedment.
3. Nails where screws would matter.
   • Nails splitting wood, over‑driven, or missing.
   • No improvement in withdrawal capacity where it’s critical.
4. 2×4 blocking where 4x4s are more appropriate.
   • Thin blocks under panel edges at high‑demand locations.
   • Limited capacity and a higher chance of splitting or pull‑out.
5. Corrosion not considered.
   • Standard zinc hardware used in damp environments.
   • Noticeable rust in 2–5 years in crawl spaces that “look dry.”
6. No documentation for the owner.
   • No as‑built drawings
   • No labeled photo sets
   • Owners have no idea what was done or how to evaluate it later

These patterns are why we built the Seismic Truth Audit™ in the first place.

 

What you actually get from a Seismic Truth Audit™

When you book a Seismic Truth Audit™, you’re not buying “another contractor opinion.” You’re buying:

• Time under your home:
  Real time in the crawl space or basement, not just looking from the hatch.
• A to‑scale drawing:
  We map your foundation, cripple walls, beams, posts, and major hardware.
• A labeled photo set:
  100+ photos, with descriptions, stored in a private folder you keep.
• Written findings:
  In plain language:
  • What we saw
  • What’s strong
  • What’s weak
  • Where it deviates from Plan Set A / FEMA / manufacturer specs
• Prioritized corrections:
  • “Critical” (things we’d fix first)
  • “Important” (next phase)
  • “Optional / nice‑to‑have”
• Itemized proposals (if you want us to do the work):
  • Clear minimum vs recommended scopes
  • Pricing for each correction or group of corrections

You can learn more about the service here:
https://www.avant-gardece.com/seismic-truth-audits/

 

When a Seismic Truth Audit™ makes sense

You should strongly consider a Truth Audit if:

• Your home was retrofitted through EBB or other programs years ago
• You bought a home and the seller said “it’s already seismically retrofitted”
• Your retrofit contractor is out of business or not returning calls
• You see new cracks, sticking doors, or sloping floors after a prior retrofit
• You simply don’t trust that the crawl‑space work you got was “done right”

If you’re starting from scratch (no known retrofit), a Seismic Safety Visit™ / Earthquake Safety Audit™ is the right first step. If work was already done and you want it checked, that’s when a Seismic Truth Audit™ is ideal.

 

How to get started

If any of this sounds like your situation and you own a home in the Greater San Francisco Bay Area, there are three simple next steps:

1. Read more about Seismic Truth Audits™
   We outline the service in detail here:
   https://www.avant-gardece.com/seismic-truth-audits/
2. Watch our seismic safety videos
   We cover retrofits, crawl spaces, soft‑story risk, water/soil issues, and more on YouTube:
   https://www.youtube.com/@Avant-GardeCE
3. Schedule a Seismic Truth Audit™ or Seismic Safety Visit™
   If you want clear, documented answers about your home – not just more guesses – start here:
   https://landing.avant-gardece.com/seismic-safety

You’ll tell us your address and whether your home has been “retrofitted” before, and we’ll recommend the right type of visit.

 

Most Bay Area homeowners with “retrofitted” homes don’t need more reassurance.
They need the truth about what was actually done – and what it would take to make their home behave the way they think it will.

That’s exactly what a Seismic Truth Audit™ is for.