Structural Remediation & Seismic Retrofit

Structural problems in residential construction are common across Los Angeles, particularly in the hillside neighborhoods of the Santa Monica Mountains, Hollywood Hills, and coastal canyons. The combination of geology, climate, and aging housing stock creates conditions that most other U.S. markets do not have to deal with. The investigation and repair process for these conditions is more systematic and more involved than most homeowners expect.

This page explains what structural remediation and seismic retrofit involve for residential properties in the Los Angeles market. It covers why structures fail, what the signs look like, how the investigation is sequenced, what the repair methods are, what they cost, and how the work is managed.

Last updated: February 2026

Why Structures Fail in Los Angeles

Los Angeles sits at the intersection of geological, climatic, and construction-history conditions that create a demanding environment for residential structures. Understanding why things fail here, specifically, is the starting point for understanding what the fix involves.

The Geology

The Santa Monica Mountains, which form the spine of the Westside's hillside neighborhoods, are a layered sequence of sedimentary rocks: sandstone, siltstone, shale, and conglomerate, with occasional outcrops of granitic rock. These formations were deposited as marine sediments, uplifted by tectonic forces, and then eroded and weathered over millions of years. The result is a geology that varies dramatically over short distances. On a single residential lot in Bel Air or the Palisades, you can encounter competent bedrock at one corner and loose alluvial fill at another.

The alluvial soils of the LA Basin, which underlie the flatlands from Beverly Hills south, are derived from the adjacent mountain ranges and deposited by ancient stream systems. These deposits alternate between sandy, well-drained layers and clay-rich layers that are highly expansive. The clay mineralogy is dominated by montmorillonite, a clay that swells dramatically when it absorbs water and shrinks as it dries. This seasonal expansion and contraction cycle, driven by LA's distinct wet and dry seasons, subjects foundations to repetitive movement that accumulates over years and decades.

Colluvium, the loose material that accumulates on hillside slopes through erosion and gravity, presents another set of conditions to account for. Colluvial deposits were not compacted or consolidated by geological processes. They sit on the surface of the hillside, often at or near the angle of repose, and they move. On hillside residential sites, foundations that bear on competent native soil or bedrock perform well; foundations that bear on colluvium are susceptible to settlement and creep, which is why the geotechnical investigation is important for identifying what the foundation is actually sitting on.

The Climate

LA's Mediterranean climate, with its long dry summers and concentrated winter rainfall, creates specific challenges for foundations and retaining structures. During drought periods, expansive clay soils shrink and pull away from foundations, creating gaps that fill with loose material. When the rains return, water enters those gaps and saturates the soil from the top down. The clay swells, but not uniformly. The differential movement between the wetted perimeter of the foundation and the still-dry soil beneath the center of the structure creates the conditions for differential settlement, the most common form of damaging foundation movement.

Extended drought periods compound the problem. California experienced severe drought conditions from 2012 through 2016 and again in 2020 through 2022. During these periods, clay soils dried to depths well below normal seasonal variation. When the rains returned, the rehydration was dramatic, and structural engineers across the Westside saw a surge in calls about new cracking, sticking doors, and settling foundations. The mechanism is straightforward: soil volume change acting on structures that were not designed for that magnitude of movement.

The Housing Stock

A significant portion of LA's hillside housing stock was built before modern building codes established the engineering standards that govern construction today. Homes built before the city's 1963 grading ordinance may sit on uncompacted fill with minimal drainage and foundation systems designed to earlier standards. Homes built before the 1971 Sylmar earthquake prompted major code revisions may predate the seismic detailing that is now standard. Current code requirements reflect decades of engineering lessons, and understanding where an older home sits relative to those standards is part of evaluating its structural condition.

Pre-code construction is particularly prevalent in the hillside neighborhoods developed in the 1920s through 1960s: the Bird Streets above the Sunset Strip, the original Bel Air estates, the older sections of Pacific Palisades, and parts of Malibu. These homes were typically built with shallow foundations, minimal drainage systems, no seismic connections between the wood frame and the concrete foundation, and retaining walls designed to the practices of the era. When these homes are purchased for renovation, or when signs of distress appear after decades of soil movement, investigation establishes what the original construction consists of and what upgrades are appropriate.

Common Failure Modes

Foundation settlement is the most common structural problem in LA residential construction. Differential settlement, where one part of the foundation settles more than another, creates the visible distress that homeowners notice: cracks in walls, doors that stick, floors that slope. Settlement is caused by soil consolidation under the foundation's load, erosion of bearing material, changes in soil moisture content, or a combination of these factors. On hillside properties, settlement is often compounded by downhill creep of the surface soils that support the uphill side of the foundation.

Retaining wall failure is the second most common problem on hillside properties. The mechanics of retaining wall failure are covered extensively on our retaining walls page, but in the context of structural remediation, the key point is that a failing retaining wall is rarely an isolated problem. The wall failure indicates that the soil it was retaining is moving, and that movement affects everything above it, including the house foundation, drainage systems, and adjacent structures.

Slope movement and hillside creep is the slow, gravity-driven downhill movement of surface soils on steep slopes. Creep is measured in fractions of an inch per year, but over decades it accumulates. On hillside properties, creep manifests as tilting retaining walls, shifting patios, separating walkways, and progressive foundation movement. Creep is not a sudden event. It is a chronic condition that requires ongoing management or definitive stabilization.

Water intrusion affecting structural elements is both a cause and a consequence of structural distress. Water that enters through waterproofing, drainage systems, or cracks in the building envelope saturates the soil around and beneath the foundation, accelerating settlement and erosion. Simultaneously, structural movement creates new pathways for water entry. Addressing both the water management and the structural condition together is what makes remediation effective, because resolving one while leaving the other in place allows the cycle to continue.

Seismic damage can be sudden and obvious, as after a significant earthquake, or cumulative and subtle. Repetitive small seismic events, which occur regularly throughout the LA basin, create fatigue in structural connections, weaken mortar joints, and gradually reduce the lateral resistance of older structures. A post-earthquake structural evaluation identifies damage that may not be visible to the homeowner, and homes that were evaluated and repaired after events like the 1994 Northridge earthquake are in a better position than those where damage went unidentified.

Post-fire structural damage has become an increasingly relevant consideration following the 2025 Palisades fires and previous fire events in Malibu, Bel Air, and the hillside communities. Fire exposure affects concrete strength, can compromise reinforcing steel, and damages the wood framing that provides lateral resistance. Structures that appear intact after a fire may have hidden heat damage. Concrete exposed to temperatures above 570 degrees Fahrenheit begins to lose compressive strength, and rebar exposed to temperatures above 1,100 degrees Fahrenheit can lose significant yield strength. A post-fire structural evaluation by a licensed engineer establishes the building's actual condition and determines what repairs are needed before rebuilding proceeds. Our fire rebuild page covers the full post-fire evaluation and reconstruction process.

Expansive soil movement is a cyclical condition driven by the wet-dry climate pattern described above. Unlike settlement, which is generally a one-directional downward movement, expansive soil creates both upward heave during wet periods and downward settlement during dry periods. The resulting cyclic loading subjects the foundation and the structure above it to repetitive stress over time.

Pre-code construction conditions are often discovered during renovation work. Opening up walls and ceilings reveals what was actually built: the actual footing sizes, the reinforcement present, the connections between elements, and how closely the original construction matches the drawings (if drawings existed at all). Identifying these conditions early in a renovation allows the structural engineer to design upgrades as part of the renovation scope, which is more efficient than discovering them mid-construction. These discoveries may trigger code-required upgrades under the California Existing Building Code (CEBC).

Signs of Structural Distress

The visible signs of structural distress are the symptoms that prompt investigation. Understanding what these signs indicate, and which ones are cosmetic versus structurally significant, is the first step in the evaluation process.

Cracks: Which Ones Matter

Not all cracks are structural. Hairline cracks in stucco and drywall are common in every home and are usually caused by normal material shrinkage, minor thermal movement, or settling that occurred shortly after construction. These cracks are cosmetic. They are typically less than 1/16 inch wide, stable over time, and not associated with other signs of movement.

The cracks that warrant investigation share certain characteristics. Diagonal cracks radiating from the corners of windows and doors are classic indicators of differential settlement. The foundation has moved unevenly, and the rigid wall framing above is cracking along the stress concentration at opening corners. Horizontal cracks in foundation walls or basement walls indicate lateral pressure from soil or water pushing against the wall beyond its capacity. This is the single most concerning crack pattern in a foundation because it indicates the wall is bending under loads it was not designed to carry. Stair-step cracks in masonry or concrete block walls follow the mortar joints in a diagonal pattern and indicate the wall is racking from differential movement. Vertical cracks in poured concrete foundations can be cosmetic if they are hairline and stable, but widening vertical cracks suggest the foundation is separating, particularly at construction joints or at locations where the footing steps.

Width matters. Cracks less than 1/16 inch are generally cosmetic. Cracks between 1/16 and 1/8 inch should be monitored. Cracks wider than 1/8 inch, or any crack that is actively growing, warrant evaluation by a structural engineer. On hillside properties, even narrow cracks should be taken seriously if they are accompanied by other signs of movement.

Other Indicators

Changes in how doors and windows operate are among the earliest indicators of structural movement. The wood framing around the opening shifts as the structure moves, and the door or window binds in its frame. Seasonal patterns (sticking in winter, operating freely in summer) often correlate with expansive soil movement. Progressive changes that worsen over time regardless of season are more consistent with ongoing settlement.

Floors that slope or feel uneven underfoot indicate differential settlement of the foundation. A marble placed on the floor will roll consistently toward the low point. Floor slope is measurable: a slope of more than 1/4 inch per 4 feet is noticeable and suggests significant differential movement.

Separation between walls and ceilings, gaps opening at the junction of interior walls and exterior walls, or visible gaps between the chimney and the house all indicate that different parts of the structure are moving independently rather than as a single unit.

Water intrusion in new locations, where water was not previously present, can indicate that structural movement has created new pathways. A crack in the foundation allows groundwater to enter. Movement at a window frame breaks the seal and allows rain penetration. In these cases, the waterproofing issue and the structural movement share a common cause.

Exterior stucco cracking patterns are particularly informative on LA homes because stucco is relatively brittle and shows movement clearly. Long diagonal cracks across the face of the building, cracks that follow the line of the foundation, and cracks that align with interior distress all point to the same underlying structural cause.

The Investigation Process

Structural remediation begins with investigation, not construction. The investigation determines what is wrong, why it is happening, and what the repair should be. A thorough investigation produces a remediation design that addresses root causes, which is what makes the repair durable.

Initial Assessment and Site Walk

The investigation typically starts with a joint site walk involving the construction manager and the structural engineer. We walk the entire property, interior and exterior, documenting every visible sign of distress: crack locations, crack widths, crack patterns, door and window operation, floor slope, retaining wall conditions, drainage conditions, and the relationship between the distress and the site's topography. This initial assessment takes 2 to 4 hours on a typical hillside property and costs $2,000 to $5,000 depending on the property size and the engineer's scope.

When a construction manager is involved during the initial assessment, the role is providing operational context that informs the engineer's evaluation: noting access constraints that will affect remediation methods, identifying areas where destructive investigation will be needed, observing drainage conditions and waterproofing performance that may be contributing to the structural condition, and developing a preliminary understanding of the remediation scope so the owner has realistic expectations about cost before the full investigation is complete.

Geotechnical Investigation

When the initial assessment indicates that soil conditions are contributing to the structural problem, a geotechnical investigation is the next step. The geotechnical engineer drills borings at strategic locations on the property, collects soil samples, conducts laboratory testing to determine soil type, bearing capacity, moisture content, and expansion potential, and evaluates the subsurface conditions that are driving the structural distress.

On hillside properties, the geotechnical investigation may also include evaluation of slope stability, the potential for landslide or debris flow, and the adequacy of existing retaining wall foundations. A typical residential geotechnical investigation with 2 to 4 borings, laboratory testing, and a written report costs $8,000 to $20,000 in the LA market. On complex hillside sites requiring deeper borings, more borings, or slope stability analysis, the cost can reach $25,000 to $40,000. Our foundation systems and geotechnical page covers the geotechnical investigation process in full detail.

Structural Engineering Evaluation

The structural engineer evaluates the building's structural system to determine the current condition, identify what needs repair, and design the remediation. This evaluation may involve non-destructive testing (visual observation, crack mapping, plumb measurements, floor level surveys), destructive testing (opening walls, exposing foundations, coring concrete), or both.

On older homes where original construction documents are unavailable, the structural engineer may need to conduct exploratory demolition to determine what the existing structure actually consists of. What type of foundation is present? What size are the footings? Is there reinforcing steel, and if so, how much? What are the connections between the foundation and the framing above? Answering these questions through selective openings gives the engineer the data needed to design an effective remediation.

Monitoring

In cases where the rate and direction of movement are unclear, the structural engineer may recommend a monitoring program before designing the repair. Monitoring instruments include crack monitors (simple devices that measure crack width change over time), inclinometers (instruments installed in boreholes to measure subsurface soil movement), and settlement markers (survey points that are re-measured periodically to track vertical movement).

Monitoring programs typically run for 3 to 12 months and provide the data needed to distinguish between active movement and historic movement that has stabilized. The distinction matters because the remediation for a foundation that is still settling is different from the remediation for a foundation that settled years ago and is now stable. Monitoring costs $5,000 to $15,000 depending on the number and type of instruments.

The Diagnosis

The investigation converges on a diagnosis: the root cause of the structural distress and the remediation approach. On hillside properties, the diagnosis frequently involves multiple contributing factors: soil movement driving foundation settlement, accelerated by drainage conditions, originally masked by waterproofing that has since deteriorated. Effective remediation addresses all of the contributing factors together, which is why the investigation phase examines the full site rather than focusing only on the most visible symptom.

Remediation Methods

The remediation method is determined by the diagnosis. This section describes the methods that are actually used on residential structural remediation projects in Los Angeles, including when each is appropriate, what it involves, and what drives the engineering decision between alternatives.

Foundation Underpinning

Underpinning is the process of extending a foundation's support to deeper, more stable soil or bedrock. It is the definitive repair for foundation settlement caused by bearing failure or soil movement in the upper soil layers. There are several methods, each suited to different conditions.

Push piers (also called resistance piers or steel piers) are steel tubes hydraulically driven through a bracket attached to the existing foundation until they reach load-bearing soil or bedrock. The structure's own weight provides the reaction force needed to push the piers to depth. Each pier is load-tested during installation, which means the installer verifies bearing capacity in real time. Push piers are effective for heavy residential structures where the foundation provides sufficient reaction weight and where the bearing stratum can be reached at reasonable depth. Typical installation depth in LA ranges from 15 to 40 feet. Push piers are installed from outside the foundation or, in some configurations, from inside a crawl space or basement. Cost per pier typically runs $1,500 to $3,000 installed, with most residential projects requiring 6 to 20 piers depending on the extent of settlement and the perimeter of affected foundation.

Helical piers (also called screw piles) are steel shafts with spiral-shaped plates that are rotated into the ground using hydraulic equipment. The helix plates develop bearing capacity through both end bearing and skin friction as they engage competent soil. Helical piers do not require the structure's weight for installation, making them suitable for lighter structures, porches, additions, and situations where the structure is not heavy enough to drive push piers. Helical piers are particularly useful on hillside properties where they can be installed at angles to resist both vertical and lateral loads. The torque required during installation is correlated with bearing capacity, providing a real-time verification of the pier's performance. Cost per pier is similar to push piers at $1,500 to $3,500 installed.

Drilled micro-piles are small-diameter (typically 4 to 12 inches) drilled and grouted piles that can be installed in confined spaces and through difficult soil conditions. They are reinforced with steel bar or steel casing and grouted under pressure to develop bearing and friction capacity. Micro-piles are well suited to residential remediation projects with tight access, challenging soil conditions, or loads that require a drilled solution. They are more expensive than push or helical piers, typically $3,000 to $8,000 per pile installed, but they offer versatility that other methods do not.

Drilled caissons are the traditional deep foundation system for hillside residential construction in LA. A caisson is a reinforced concrete shaft drilled to bedrock or competent bearing material. Typical residential caissons are 18 to 36 inches in diameter and can reach depths of 30 to 60 feet or more on steep hillside sites. When existing foundations on hillside properties need additional support because the original caissons were undersized or did not reach adequate bearing, the remediation may involve supplemental caissons drilled to proper depth and connected to the existing foundation through new grade beams. Caisson remediation is the most expensive underpinning method, with individual caissons costing $10,000 to $50,000 depending on diameter, depth, and access conditions.

The engineering decision between these methods depends on the soil conditions revealed by the geotechnical investigation, the structural loads, the access constraints of the site, and the budget. There is no universally "best" method. On many remediation projects, multiple methods are used: push piers under the main foundation perimeter, helical piers under a lighter wing or addition, and caissons where the loads or soil conditions require them.

Concrete Repair

Epoxy injection is the standard repair method for structural cracks in poured concrete foundations and walls. The process involves sealing the surface of the crack, installing injection ports at regular intervals, and injecting structural epoxy under pressure to fill the crack and restore the concrete's structural continuity. Epoxy injection bonds the cracked concrete with a material that is stronger than the concrete itself, restoring the original structural capacity. It is most effective on cracks that have stabilized - that is, the movement that caused the crack has been arrested by underpinning or other stabilization. Stabilizing the movement first ensures the epoxy repair is durable, because the repaired section can then carry the loads it was designed for.

Carbon fiber reinforcement uses high-strength carbon fiber fabric bonded to the concrete surface with structural epoxy to add tensile and flexural capacity. Carbon fiber strips applied to the interior face of a bowing basement wall or foundation wall can arrest inward movement and maintain the wall's position. Carbon fiber is also used to strengthen concrete beams, columns, and slabs where additional reinforcement capacity is needed. The material is thin, lightweight, and can be installed with minimal concrete removal compared to conventional reinforcement methods. Cost for carbon fiber wall reinforcement typically runs $100 to $200 per linear foot of wall, installed.

Shotcrete reinforcement involves applying reinforced shotcrete (pneumatically placed concrete) over existing concrete surfaces to add structural capacity. On foundation walls and retaining walls that are too deteriorated for injection repair, a new layer of reinforced shotcrete can be applied to the inside or outside face to create a composite section with increased capacity. This method requires excavation to expose the surface, surface preparation, rebar installation, and shotcrete placement by licensed nozzlemen.

Retaining Wall Remediation

Retaining wall remediation on residential hillside properties involves a threshold decision: repair the existing wall or replace it. The decision depends on the wall's condition, the cause of the distress, the original construction quality, and the cost comparison between repair and replacement.

Repair is appropriate when the wall is structurally sound and has experienced localized issues: minor cracking, drainage system problems that caused localized movement, or erosion at the base. Repair typically involves restoring the drainage system, patching or injecting cracks, and addressing the root cause. Repair costs are a fraction of replacement costs and are a good investment when the underlying wall has sound structural capacity.

Replacement is appropriate when the wall has experienced structural changes beyond what repair can address: significant rotation, horizontal cracking through the stem, footing displacement, or reinforcement corrosion. On hillside properties, wall replacement includes provisions for supporting the retained soil during demolition and new construction. This may involve temporary shoring, slot-cut construction sequences, or in some cases, building a new wall in front of the existing wall (a "sister wall") while leaving the original in place. Our retaining walls page covers the repair-versus-replacement decision framework, wall types, and construction methods in full detail.

Drainage Remediation

Drainage is frequently a contributing factor in structural problems on hillside properties. Water saturating the soil behind retaining walls increases lateral pressure. Water beneath foundations erodes bearing material. Water in expansive clay soils drives the cyclical swell-shrink movement that affects foundations over time. Many remediation projects include drainage remediation as part of the scope because the structural fix alone does not address the mechanism that caused the problem.

Drainage remediation typically involves installing or replacing subdrains (French drains) behind retaining walls and alongside foundations, installing area drains and catch basins to capture surface water, regrading surfaces to direct water away from structures, and connecting all drainage systems to an appropriate discharge point (typically the street). On hillside properties, drainage remediation can also involve installation of interceptor drains upslope of the structure to capture subsurface water before it reaches the foundation.

Drainage remediation costs vary widely depending on the extent of work and the access conditions. A straightforward subdrain installation behind a retaining wall might cost $15,000 to $40,000. A comprehensive site drainage system on a hillside property with multiple retaining walls and complex topography can cost $50,000 to $150,000 or more.

Slope Stabilization

When the structural problem is caused by slope movement rather than (or in addition to) foundation inadequacy, slope stabilization is required. Methods include tiebacks drilled through the failing mass and anchored in stable material behind the slip plane, soil nails installed in a grid pattern to reinforce the slope, retaining wall construction to buttress the toe of the slope, and dewatering systems to lower the water table within the slope and reduce the pore water pressures that drive instability.

Slope stabilization is typically the largest-scale category of residential remediation because the work extends beyond the building footprint to address the slope itself. Stabilizing a slope on a hillside property can involve work across the full lot width and significant depth, with costs ranging from $100,000 to $500,000 or more depending on the geology, the height of the slope, and the chosen stabilization method. Once completed, a properly stabilized slope provides long-term support for the structures above it.

Shoring and Temporary Support

Before remediation work proceeds on a structure that has experienced movement, temporary support stabilizes the building during the repair. Shoring systems include temporary steel posts and beams to support floors and roofs while foundation work proceeds below, temporary bracing to maintain wall positions, and needle beams that transfer loads from the existing structure to temporary foundations while the permanent foundation is repaired or replaced.

Shoring design for remediation accounts for the structure's current condition, not just its original design capacity. The structural engineer analyzes the actual loads and load paths as they exist today and designs the shoring to maintain the structure safely throughout the repair process. Shoring costs on residential remediation projects typically range from $20,000 to $100,000 depending on the scope.

Seismic Retrofit

Seismic retrofit is the strengthening of an existing structure to better resist earthquake forces. Unlike the remediation work described above, which responds to damage that has already occurred, seismic retrofit addresses vulnerability before an earthquake occurs.

LA's Mandatory Soft-Story Retrofit Ordinance

In 2015, the City of Los Angeles passed Ordinance 183,893, mandating seismic retrofit of certain vulnerable building types. The ordinance targets two categories of structures: wood-frame soft-story buildings and non-ductile concrete buildings, both built before January 1, 1978.

The soft-story program applies to multi-story wood-frame buildings with ground-floor parking or similar open space creating a "soft story," containing four or more dwelling units, permitted or built before 1978. LADBS identified approximately 13,500 buildings in Los Angeles that fall within the scope of the ordinance. Each property owner received an Order to Comply, with compliance timelines based on building priority: 2 years to submit retrofit plans, 3.5 years to obtain permits, and 7 years to complete construction.

The soft-story ordinance does not apply to single-family homes or buildings with three or fewer units. However, the engineering principles behind the ordinance - that pre-1978 wood-frame structures on raised foundations are vulnerable to earthquake damage - apply equally to single-family hillside homes.

Voluntary Retrofit for Single-Family Homes

For single-family homeowners, seismic retrofit is voluntary. The homes most commonly retrofitted are those built before 1980 on raised foundations. The most common retrofit scope for pre-1980 hillside homes includes three elements.

Foundation bolting secures the wood-frame structure to the concrete foundation using anchor bolts or retrofit brackets. Many older homes in LA were built with the wood sill plate resting on the concrete foundation, held in place by gravity and sometimes a few nails. Foundation bolting creates a positive mechanical connection that keeps the house anchored to its foundation during seismic shaking, resisting the lateral forces that would otherwise cause the structure to shift.

Cripple wall bracing reinforces the short wood-stud walls between the foundation and the first floor. In homes with crawl spaces, these cripple walls are the most flexible element in the lateral force path. Bracing them with structural plywood sheathing, specified nailing patterns, and hold-down hardware at the ends creates a rigid connection between the foundation and the floor above, allowing the structure to resist lateral forces as a unified system.

Shear transfer ties connect the floor system, wall system, and foundation to create a continuous load path for lateral forces. This ensures that earthquake forces are transferred smoothly from the roof through the walls, through the floor, and into the foundation, allowing the entire structure to work together as a single unit during seismic events.

More Extensive Retrofit

On hillside homes and larger or more complex structures, additional retrofit measures beyond basic bolt-and-brace may be appropriate. These include adding interior shear walls to provide lateral resistance in both directions, strengthening connections between floors, walls, and roof to create redundant load paths, supplementing existing foundations with new footings, grade beams, or piers, and in some cases, adding steel moment frames at garage openings or other large wall openings to stiffen the ground floor.

The scope and cost of comprehensive retrofit depend on the home's structural system, its age and condition, and the specific seismic hazards at the site. On hillside properties, where the foundation system may include caissons, grade beams, and retaining walls, a comprehensive retrofit can cost $40,000 to $150,000 or more. For homes undergoing major renovation, the incremental cost of incorporating seismic retrofit into the renovation scope is typically much less than performing the retrofit as a standalone project.

Retrofit Combined with Renovation

For homeowners planning a major renovation, combining seismic retrofit with the renovation work is the most cost-effective approach. Walls are already open. The contractor is already on site. The structural engineer is already involved. Adding bolt-and-brace, shear walls, and connection upgrades to an open renovation costs a fraction of what it would cost as a standalone project because the access and demolition costs are already incurred.

This is a common consideration during preconstruction for renovation projects. When a renovation triggers the threshold for seismic upgrades under the California Existing Building Code (CEBC), the retrofit is no longer optional; it is code-required. But even when the renovation scope does not trigger mandatory upgrades, performing retrofit work while the walls are open typically costs 20 to 40 percent of the standalone retrofit cost because the access and demolition costs are already incurred.

Insurance Implications

Standard homeowner's insurance in California covers specific named perils but excludes earthquake damage. Earth movement, including earthquake shaking, settlement, and landslide, falls outside standard policy coverage. Separate earthquake insurance provides this coverage.

The California Earthquake Authority (CEA) is the primary source of residential earthquake insurance in California. CEA policies cover structural damage to the dwelling, personal property, and additional living expenses, subject to deductibles ranging from 5% to 25% of the dwelling coverage limit. A verified seismic retrofit can qualify the homeowner for lower deductibles and premium discounts of up to 25%, which means the retrofit investment has ongoing financial value beyond the structural benefit.

The California Earthquake Brace + Bolt (EBB) program offers grants of up to $3,000 to help homeowners in qualifying ZIP codes pay for foundation bolting and cripple wall bracing. The program is administered by the California Residential Mitigation Program (CRMP) and requires that the work be performed by a FEMA-trained, California-licensed contractor using approved methods.

Permitting and Code Requirements

Remediation work on existing structures in Los Angeles is governed by the California Existing Building Code (CEBC), which has largely replaced Chapter 34 of the California Building Code (CBC) for work on existing buildings. The CEBC establishes requirements for repairs, alterations, additions, and changes of occupancy to existing structures, and its provisions determine how much of the existing building must be brought into compliance with current code when repair or renovation work is performed.

When Permits Are Required

LADBS requires permits for structural repairs to foundations, retaining walls, and the building's lateral force-resisting system. This includes foundation underpinning, foundation replacement, structural concrete repair, retaining wall replacement, shoring installation, and seismic retrofit. The permit application requires engineered drawings stamped by a licensed structural engineer or civil engineer, a geotechnical report (for foundation and retaining wall work), and in many cases a grading permit for associated excavation.

Minor cosmetic crack sealing and routine maintenance are generally exempt from permit requirements. However, any work that affects the structural capacity or load path of the building requires a permit. The line between "maintenance" and "structural repair" is a judgment call made by LADBS, and erring on the side of permitting is the safer approach.

Triggered Improvements

One of the most consequential code provisions for remediation projects is the concept of triggered improvements. When repair work on one element of the building triggers a code threshold, other elements of the building may be required to comply with current code, even though they were not part of the original repair scope.

Under the CEBC, the triggers depend on the scope and cost of the work relative to the building's value. When the cost of structural repairs exceeds certain thresholds, or when the scope of work constitutes a "substantial structural alteration," the building official may require that the entire lateral force-resisting system be evaluated and brought into compliance with current standards. Identifying these thresholds early allows the owner to see the full scope and budget the project realistically from the start, rather than encountering the requirement during plan check.

Understanding these triggers during preconstruction matters for budgeting. When a construction manager and structural engineer evaluate the code implications of the proposed remediation scope before the permit application is submitted, the owner can see the full cost picture before committing to the work.

Special Inspection

Structural remediation work in Seismic Design Categories D through F (which includes all of Los Angeles) requires special inspection by a deputy inspector. The deputy inspector is a licensed or certified inspector retained by the owner (not the contractor) to observe critical construction activities and verify that the work conforms to the approved plans and specifications.

For remediation work, deputy inspection is required during rebar placement, concrete pouring, post-tensioning operations, structural steel connections, and other specified operations. The deputy inspector's reports are submitted to LADBS and become part of the project's permanent record. Deputy inspection costs typically run $150 to $300 per hour, with total inspection costs depending on the scope and duration of the structural work.

For detailed information on the permitting process, plan check timelines, and inspection requirements, see our Los Angeles permitting overview.

Cost Ranges

The following cost ranges reflect the LA luxury residential market, including hillside access constraints, premium subcontractor pricing, and the engineering coordination typical of these projects. These are LA-specific ranges and differ from the national averages published by home improvement websites.

Remediation costs become more precise as investigation progresses. The ranges above are based on project experience and are useful for preliminary planning. Final costs depend on the specific conditions found during investigation and the engineering approach to the remediation design. For broader context on how these costs fit within the LA residential construction market, see our construction costs page.

The Construction Manager's Role in Remediation

Remediation projects have evolving scope by definition. Conditions concealed behind finishes and below grade are confirmed as construction proceeds, and each confirmation refines the scope. The geotechnical engineer observes bearing conditions during pier installation that inform design adjustments. The structural engineer identifies additional conditions during construction that were concealed behind finishes. Each of these observations leads to real-time decisions about scope, budget, and schedule.

This is the environment where a construction manager's coordination role is most relevant. The CM coordinates the structural engineer's field observations with the geotechnical engineer's recommendations and the contractor's operations. The CM prices work as scope develops so the owner has current budget information at decision points. And the CM maintains communication with the owner about what is being found and what it means for the project.

Coordination During Investigation

During the investigation phase, the CM coordinates the scheduling and logistics of geotechnical borings, arranges access for the structural engineer's evaluation, manages the communication between the owner and the engineering team, and develops preliminary cost estimates based on emerging findings. This involvement allows the owner to track the cost implications as the investigation progresses rather than receiving a single number at the end.

Field Coordination During Construction

During remediation construction, the CM manages the daily coordination between the field crew and the engineering team. When the contractor exposes a foundation and finds conditions different from the design assumptions, the CM contacts the structural engineer, arranges for a site visit, facilitates the design revision, prices the scope change, communicates the impact to the owner, and keeps the work moving. This cycle can happen multiple times on a single remediation project.

Change Management

Scope changes on remediation projects are a normal part of the process. They are the result of working on a structure where conditions are confirmed as construction exposes them. Managing these changes involves documenting the condition found, obtaining the engineer's revised direction, pricing the additional work, presenting the owner with clear options, and proceeding with the owner's informed approval. Our CMAR page explains how this delivery model works, and our Why CMAR page explains the rationale for using it on complex projects.

Frequently Asked Questions

This page is published by Benson Construction Group, Inc., CSLB License #1007735. The information provided is based on professional experience managing residential construction projects in Los Angeles and is intended as general guidance. Specific project conditions vary. Code citations reference regulations in effect at the time of publication; verify current requirements with the applicable jurisdiction before making decisions. This page is not a substitute for professional consultation with a licensed contractor, engineer, geologist, or attorney for your specific situation.