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A-04Danville, CA

House Bolting and Foundation Repair in Danville, CA

Danville's median home was built in 1980 (Census ACS), right at the Brace + Bolt cutoff: older ranch homes on raised foundations are bolting and bracing candidates, while many 1980s and later houses sit on slabs. Danville issues its own building permits; Alamo, Blackhawk and Diablo go through Contra Costa County.

Single-story 1960s ranch home with a brick planter and green lawn in a leafy Danville neighborhood with golden foothills behind
Older Danville ranch homes are the bolting candidates.

01At a glance

Danville homes at a glance

1980
Median year built
77.4%
Single-family detached homes
85.5%
Owner-occupied
43,302
Residents (2025 est.)

Housing figures: U.S. Census Bureau ACS 2020–2024; population: Vintage 2025 estimate (QuickFacts).

02Two eras

Raised foundation or slab? Check first

Older homes (pre-1980)Newer homes (1980+)
Typical foundationRaised perimeter with crawlspaceOften slab-on-grade
Retrofit candidate?Often: bolting and cripple-wall bracingRarely
Common foundation issuesOld posts and girders, unbolted sillsSlab cracks, settlement, drainage
Brace + BoltPossible, if selectedNot eligible (built 1980 or later)

A crawlspace vent along the base of the walls is a quick sign of a raised floor.

03House bolting

House bolting in Danville

"House bolting" means adding anchor bolts and plate washers that tie the sill plate to the foundation, usually with plywood bracing of the cripple walls. A bolt-only job typically runs $1,500–$3,500+ and a full bolt-and-brace retrofit $3,000–$7,000+ (customhome.us; CRMP). How a retrofit works →

04Permits

Danville permits vs the County

Inside town limits, permits and inspections go through the Town of Danville Permit Center. Unincorporated Alamo, Blackhawk and Diablo use Contra Costa County, and Blackhawk and Diablo homes may also need HOA approval.

05Nearby

Alamo, Blackhawk and Diablo

Alamo (1978 median build year) has many older large-lot homes; confirm ZIP 94507 with CRMP's Brace + Bolt lookup. Blackhawk (1988) is mostly newer construction where slab and drainage issues are more common than retrofits. Diablo is a small foothill community with a mix of ages.

06Brace + Bolt

Brace + Bolt in Danville

Danville ZIPs 94506 and 94526 were on the 2025 eligible list. The grant pays up to $3,000 toward the retrofit (CRMP). Checklist and how the draw works → For sloping floors in older Danville homes, see leveling and underpinning.

09Questions

Danville questions

Does my Danville house need bolting?
If it was built before 1980 on a raised foundation and you cannot see anchor bolts with square plate washers along the sill plate in the crawlspace, it is a candidate. Slab houses generally are not.
Who issues permits for Alamo or Blackhawk homes?
Contra Costa County, not the Town of Danville.

Sources · read October 4, 2026

  1. U.S. Census Bureau QuickFacts (ACS 2020–2024)
  2. customhome.us (a Bay Area contractor): seismic retrofit cost
  3. CRMP: program FAQs
  4. Town of Danville: Permit Center
  5. Contra Costa County: building or grading permits
  6. CRMP: Earthquake Brace + Bolt retrofit

Older Danville house that isn't bolted?

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