Post-Wildfire Residential Rebuild
Altadena, CA
Overview
After a devastating wildfire destroyed homes throughout the community, Moment mobilized quickly to support a homeowner rebuilding a 1,600 SF single-family residence. We performed a geotechnical investigation on the cleared lot within the San Gabriel Mountain foothills alluvial fan system.
The Challenge
The lot was located in an active burn zone with remnant foundations, debris, and fire-altered surface soils. The alluvial fan setting near Eaton Canyon also raised questions about debris flow susceptibility and whether fire had compromised the bearing capacity of the underlying soils.
Our Approach
Moment advanced two hand-auger borings to 10 ft and 5 ft using a California Sampler. Despite the fire damage at the surface, the native alluvial fan deposits proved to be medium to coarse, dense to very dense reddish-brown sand with gravel and trace fines (SM/SP) — excellent foundation-bearing material. Dry densities ranged from 106.7 to 115.5 pcf with moisture contents of 4.4–7.8%. The Expansion Index tested at only 12 (Very Low), and no groundwater was encountered to 10 ft.
Results
The investigation confirmed that shallow spread foundations with remedial grading of surface soils would fully support the new home. Bearing capacity of 2,000 psf with less than 0.5 inches total settlement allowed the owner to move forward quickly with rebuilding.
Technical Summary
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We deliver soil reports, foundation recommendations, grading plans, and stormwater compliance — on schedule and ready for permitting.