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CRC R403.1 — Marin Foundation Requirements

Updated May 18, 2026
Continuous footings required; minimum 12 inch depth below natural grade; expansive soil considerations apply countywide.

CRC R403.1 as enforced by Marin County requires continuous concrete footings under all bearing walls with minimum 12 inch depth below natural grade. Marin soils frequently include expansive clays (Bay Mud, Franciscan-derived) requiring geotechnical evaluation per CRC R403.1.8. Pier and grade beam systems are common in hillside lots (more than 20% slope).

TAGS
marinfoundationsfootingsexpansive-soilCRC
DETAILS
edition
2022
adopted by
["ca-marin","ca-marin-county"]
code system
CRC
confidence tier
primary
jurisdiction label
Marin County, CA
SOURCES
🔗https://codes.iccsafe.org/codes/california/CARC2022P1
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