Table of Contents

• The Silent Crisis Hiding Under Bay Area Homes Right Now (#silent-crisis)
• Exact Types of Foundation Damage We’re Seeing This Week (#damage-types)
• Neighborhoods Where Foundation Cracks Hit Hardest (#worst-neighborhoods)
• Warning Signs in Your House (Don’t Wait for These) (#warning-signs)
• Immediate Post-Storm Actions (November 17–25) (#immediate-actions)
• Permanent Foundation Protection That Actually Works (#permanent-protection)
• Your 2025 Bay Area Foundation Safety Checklist (#checklist)
• Key Takeaways & Free Inspection Offer (#takeaways)

The Silent Crisis Hiding Under Bay Area Homes Right Now

While the news has moved on from the November 13–15 atmospheric river, structural engineers and foundation contractors are completely slammed. Thousands of single-family homes across San Francisco, Oakland, Marin, and the Peninsula now have new cracks, settling, or hydrostatic damage that won’t show up until walls start separating or floors slope noticeably — often months from now.

The average repair bill we’re quoting this week is $28,000–$115,000 depending on the foundation type and how long water sat against it. Most standard homeowner policies exclude this entirely. The good news: 85–90% of the damage we’re seeing could have been prevented with upgrades that cost 10–20% of the repair.

‍

Exact Types of Foundation Damage We’re Seeing This Week

The storm created three main categories of problems. First, hydrostatic pressure cracks — horizontal lines appearing 6–24 inches below grade on poured concrete or block basement walls — showed up overnight in Noe Valley, Bernal Heights, and Marin hillside homes when water built up against the foundation for 24+ hours. Second, differential settling hit slab-on-grade homes in Daly City, East Oakland, and San Leandro when saturated soil under one corner of the house turned to mush while the rest stayed firm. Third, stem-wall separation and spalling struck 1920s–1950s stucco homes in the Sunset and Richmond when downhill water soaked the soil right under the footing, causing the concrete to crumble and rebar to rust.

Neighborhoods Where Foundation Cracks Hit Hardest

Noe Valley and Bernal Heights lead the pack — steep lots with old Victorians on shallow crawlspaces or un-reinforced basements saw the most dramatic movement. Marin County homes built on fill or bay mud (Mill Valley, Tiburon, Sausalito) reported ⅛–½ inch new cracks almost overnight. East Oakland and San Leandro slab homes are showing classic “dish” settling where the center sinks and the edges lift. The Sunset and Richmond districts have hundreds of garage stem walls that now have visible bowing and flaking concrete from water that poured off flat roofs and sat against the foundation for days.

Warning Signs in Your House (Don’t Wait for These)

Look for new diagonal cracks above doors or windows that are wider than ⅛ inch at the top, doors that suddenly stick or won’t latch properly, sloping floors you can feel when walking across the room, gaps between baseboards and the floor, or water stains and efflorescence (white powdery residue) on basement walls. Any of these appearing after November 13 means the clock is ticking — water is still working inside the concrete.

‍

Immediate Post-Storm Actions (November 17–25)

If you had standing water against your foundation for more than 12 hours, act fast. First, remove any wet soil touching the foundation and replace it with compacted gravel to restore drainage. Run commercial dehumidifiers in crawlspaces and basements 24/7 for at least 10 days — mold and further weakening start fast. Have a licensed structural engineer (not a contractor) inspect within the next 7 days — they’ll tell you if movement is active or stable. Get at least three bids for epoxy or polyurethane crack injection if leaks are active — this stops water instantly and costs $1,200–$4,500 versus $25,000+ for full excavation later.

Permanent Foundation Protection That Actually Works

The hierarchy that delivers the highest return starts with surface water control: seamless gutters with leaf guards and downspouts extended 10+ feet from the house will prevent 70–80% of future hydrostatic issues for $2,500–$5,000. Next, proper grading — ensuring the first 10 feet around your home slopes away at least 6 inches — combined with French drains or curtain drains on the uphill side runs $6,000–$14,000 and blocks another 15–20% of risk. For homes with chronic problems, full foundation waterproofing membrane plus interior or exterior drain tile costs $18,000–$45,000 but delivers near-total protection. Adding carbon fiber straps or steel I-beams for bowing walls costs $1,200–$2,000 per strap and is often covered under earthquake retrofit grants. Finally, crawlspace encapsulation with a 20-mil vapor barrier, sealed vents, and commercial dehumidifier ($8,000–$15,000) keeps the wood and soil under your house bone-dry year-round. Most clients recoup these upgrades with the first claim they never have to file.

‍

Your 2025 Bay Area Foundation Safety Checklist

Walk your house today and check these boxes:

• Water pooled against foundation longer than 12 hours during the storm? → Schedule engineer this week  
• New cracks wider than a credit card anywhere on walls or floor? → Photo + measure daily  
• Downspouts end closer than 6 ft to house? → Extend before next rain  
• Soil touches siding or stucco anywhere? → Expose foundation and add gravel  
• Crawlspace or basement still smells damp? → Run dehumidifier + book encapsulation quote  
• No sump pump or battery backup? → Install before December storms

Key Takeaways & Free Inspection Offer

Bay Area Foundation Damage November 2025 Summary

• The storm just created cracks and settling that will cost homeowners millions — most of it preventable.

• Average repair right now: $28,000–$115,000. Average prevention cost: under $15,000.

• Control surface water first — gutters + grading + extensions stop 80–90% of problems.

• Don’t wait for walls to separate — act this week.  

Which neighborhood are you in and did you spot any new cracks after the storm? Comment below — you’re not alone.

‍