FIELD NOTE · SUPPLEMENTAL SET
The ground did not burn: the reports a rebuild owes before anyone frames it
ISSUEDJULY 11, 2026DRAWN BY THE NIGHTLY SWEEP
The house burned. The ground under it did not, and the ground is what gets investigated first.
Two departments run the two burn areas. The Palisades is the City of Los Angeles and answers to LADBS. Altadena is unincorporated county and answers to LA County Public Works. Both wrote rebuild instructions in 2025. Both ask what is underneath a lot. They answer it by completely different methods, and a contractor working both sides carries two rulebooks that disagree on when a lot needs looking at.
The City drew a map. The County set a depth.
Both owe a combined geology and soils report. Everything outside those two colors is treated as relatively flat and typically owes no combined report at all.
Read the second zone again. Yellow is not about the lot. It is about the hill above the lot, which somebody else owns. A flat parcel lands in the same report requirement as the slope that will eventually deliver material onto it. Water and debris run downhill onto ground with no slope of its own. The map is the only part of either document that says so.
The County never drew a map. Its trigger is what the demolition did to the dirt. Take the slab out and a compaction report is required if soil was disturbed deeper than 12 inches. A licensed geotechnical or civil engineer prepares it.
A soils report is a separate question there, and the answer is often no. A conventional raised or slab-on-grade foundation with continuous footings, designed to minimum standards, does not need one. Caissons and deep piles do. So do geotechnical hazards, basement walls, and certain other criteria.
2h:1v THE SLOPE THAT PUTS A PALISADES LOT IN THE ORANGE ZONE 5 feet EXCAVATION DEPTH THAT ORDERS A SOILS REPORT IN THE CITY 12 inches DISTURBANCE DEPTH THAT ORDERS A COMPACTION REPORT IN THE COUNTY
Two different questions. The City asks where the lot sits. The County asks what the demolition crew did.
Neither one asks how badly the house burned.
That is real relief and it is worth reading twice. The fill still gets investigated. What got waived is the lab work, and the engineer who signs the determination owns it either way.
Old reports get similar treatment. An existing geotechnical report can be used again if its approval letter is dated within 10 years of the Mayor's emergency order. But a report approved before the 2019 California Building Code has to be updated for seismic design parameters. The bulletin names them. Seismic slope stability analyses, and seismic lateral earth pressures. A consultant reusing another firm's work must state in writing that they reviewed it, concur with it, and assume responsibility for the data.
Previous remedial repairs may stay. Old foundation and slope improvements are allowed to remain where the geotechnical consultants find no potential instability. The retaining wall that held keeps holding.
On the City side, reusing the slab and foundation is permitted if a California-licensed professional structural engineer or architect evaluates the foundation system and affirms it is in satisfactory condition. Documentation goes to LADBS for review and approval. It may include observations and tests.
The County writes it harder. The determination shall be based upon thorough testing and forensic analysis. The design professional fills out a form built for exactly this, Reuse of Existing Foundation Systems in a Fire Damaged Structure. That same professional verifies everything buried in the slab is fit for continued use, meaning the drain, waste, vent, water, mechanical and electrical. Conduit may stay. Every under-slab electrical conductor comes out.
A reused foundation still owes the slope setback. It sits where it sits. The code it has to satisfy is the current one, not the one it was poured under. A soils engineer can recommend a reduced setback and the building official can approve it, and that is the whole path.
The structure going up on top falls under the 2025 California Building Code, in force since January 1, 2026. That code references ASCE 7-22. The 2022 code referenced ASCE 7-16. Anyone carrying seismic values forward from plans drawn under the last cycle is carrying the wrong ones.
Nothing else got waived. Like-for-like rebuilds still meet the current building code, the current fire code and the current health and safety code. LADBS did drop the grading pre-inspection, unless it decides otherwise or lateral support gets removed. It also let the soils engineer self-certify the bottom inspection and the compaction report, filed with the Grading Division for the record. Those are scheduling concessions.
The reports themselves are still owed. So are seismic hazard evaluations, meaning earthquake-induced slope stability, liquefaction analysis or a fault investigation, on any project that is not exempt.
Sixteen thousand two hundred fifty-one structures were destroyed across the two fires. What follows on those lots is a geotechnical job before it is a framing job. The first trades on most of them are the soils engineer, the engineering geologist and the grading contractor, months ahead of anybody who owns a nail gun. Behind them comes a roofing market measured in years. Filings scored nightly for grading contractors and for structural contractors put the burn-area work in front of the trades in the order the ground releases it.
The lot in the yellow zone never had a slope on it. It gets the same report as the hill, because of where the water goes.
Two departments run the two burn areas. The Palisades is the City of Los Angeles and answers to LADBS. Altadena is unincorporated county and answers to LA County Public Works. Both wrote rebuild instructions in 2025. Both ask what is underneath a lot. They answer it by completely different methods, and a contractor working both sides carries two rulebooks that disagree on when a lot needs looking at.
The City drew a map. The County set a depth.
Orange, yellow, and everything else
LADBS published the Palisades Geohazard Risk Assessment Zones, PGRAZ on the plans. It sits in Information Bulletin P/BC 2025-157, effective April 15, 2025, and it shades two zones. Orange covers sites on or next to steep slopes, in general steeper than 2h:1v, and potential landslide areas. Yellow covers sites at the bottom of steep slopes, prone to be affected by mudslide debris.Both owe a combined geology and soils report. Everything outside those two colors is treated as relatively flat and typically owes no combined report at all.
Read the second zone again. Yellow is not about the lot. It is about the hill above the lot, which somebody else owns. A flat parcel lands in the same report requirement as the slope that will eventually deliver material onto it. Water and debris run downhill onto ground with no slope of its own. The map is the only part of either document that says so.
Five feet, and twelve inches
Off the map, the City triggers on excavation. A soils report is required for excavations deeper than 5 feet. It is also required for any excavation that removes lateral support from an adjacent property, a structure or the public way. Pull an existing shallow foundation during demolition and a grading permit for removal and recompaction is owed on top of that.The County never drew a map. Its trigger is what the demolition did to the dirt. Take the slab out and a compaction report is required if soil was disturbed deeper than 12 inches. A licensed geotechnical or civil engineer prepares it.
A soils report is a separate question there, and the answer is often no. A conventional raised or slab-on-grade foundation with continuous footings, designed to minimum standards, does not need one. Caissons and deep piles do. So do geotechnical hazards, basement walls, and certain other criteria.
2h:1v THE SLOPE THAT PUTS A PALISADES LOT IN THE ORANGE ZONE 5 feet EXCAVATION DEPTH THAT ORDERS A SOILS REPORT IN THE CITY 12 inches DISTURBANCE DEPTH THAT ORDERS A COMPACTION REPORT IN THE COUNTY
Two different questions. The City asks where the lot sits. The County asks what the demolition crew did.
Neither one asks how badly the house burned.
Fills older than 1963
The City code carries a date. LABC Section 7011.6 makes the project soils engineer investigate fills older than April 25, 1963. The bulletin softens the testing rather than the investigation. Testing the old fill is not required, as long as the consultants determine the fill is suitable for what goes back on it. Where the soils engineer expects significant settlement is still coming, the bulletin points at mat foundations instead of deep piles.That is real relief and it is worth reading twice. The fill still gets investigated. What got waived is the lab work, and the engineer who signs the determination owns it either way.
Old reports get similar treatment. An existing geotechnical report can be used again if its approval letter is dated within 10 years of the Mayor's emergency order. But a report approved before the 2019 California Building Code has to be updated for seismic design parameters. The bulletin names them. Seismic slope stability analyses, and seismic lateral earth pressures. A consultant reusing another firm's work must state in writing that they reviewed it, concur with it, and assume responsibility for the data.
Previous remedial repairs may stay. Old foundation and slope improvements are allowed to remain where the geotechnical consultants find no potential instability. The retaining wall that held keeps holding.
The slab that stayed
Both departments let an owner reuse the existing foundation. Neither lets anybody eyeball it.On the City side, reusing the slab and foundation is permitted if a California-licensed professional structural engineer or architect evaluates the foundation system and affirms it is in satisfactory condition. Documentation goes to LADBS for review and approval. It may include observations and tests.
The County writes it harder. The determination shall be based upon thorough testing and forensic analysis. The design professional fills out a form built for exactly this, Reuse of Existing Foundation Systems in a Fire Damaged Structure. That same professional verifies everything buried in the slab is fit for continued use, meaning the drain, waste, vent, water, mechanical and electrical. Conduit may stay. Every under-slab electrical conductor comes out.
A reused foundation still owes the slope setback. It sits where it sits. The code it has to satisfy is the current one, not the one it was poured under. A soils engineer can recommend a reduced setback and the building official can approve it, and that is the whole path.
The structure going up on top falls under the 2025 California Building Code, in force since January 1, 2026. That code references ASCE 7-22. The 2022 code referenced ASCE 7-16. Anyone carrying seismic values forward from plans drawn under the last cycle is carrying the wrong ones.
What actually got waived
The zoning relief got the headlines. A like-for-like rebuild does not have to comply with current zoning, and the Mayor's emergency order waives zoning for eligible City projects outright. That is the part everybody repeated. It is about how big the house is and where it sits on the lot, which is a drawing question.Nothing else got waived. Like-for-like rebuilds still meet the current building code, the current fire code and the current health and safety code. LADBS did drop the grading pre-inspection, unless it decides otherwise or lateral support gets removed. It also let the soils engineer self-certify the bottom inspection and the compaction report, filed with the Grading Division for the record. Those are scheduling concessions.
The reports themselves are still owed. So are seismic hazard evaluations, meaning earthquake-induced slope stability, liquefaction analysis or a fault investigation, on any project that is not exempt.
Sixteen thousand two hundred fifty-one structures were destroyed across the two fires. What follows on those lots is a geotechnical job before it is a framing job. The first trades on most of them are the soils engineer, the engineering geologist and the grading contractor, months ahead of anybody who owns a nail gun. Behind them comes a roofing market measured in years. Filings scored nightly for grading contractors and for structural contractors put the burn-area work in front of the trades in the order the ground releases it.
The lot in the yellow zone never had a slope on it. It gets the same report as the hill, because of where the water goes.