Deep Foundation Costs in Los Angeles

What caisson-supported hillside foundations actually cost on complex residential projects, and why the number changes between bid day and the last pour.

If you are building on a hillside site in Los Angeles and just received a foundation cost number that seems staggering, this page is for you. Deep foundation work on complex residential projects - CIDH caisson piles drilled to bedrock, grade beams, retaining walls, slope stabilization, staged earthwork - costs dramatically more than conventional flat-lot foundations, and the generic pricing you will find online has almost nothing to do with what these systems actually cost in the field. The numbers below are drawn from competitive bids on real hillside projects we have managed throughout the greater Westside, including Pacific Palisades, Malibu, Bel Air, Beverly Hills, and Brentwood. They are organized as unit costs - cost per linear foot, per square foot, per cubic yard, per hour - so you can scale them to your own project regardless of size.

Last updated: March 2026

About This Page
This page is written by Jeff Benson, Principal of Benson Construction Group, drawing on 24 years managing complex residential construction in Los Angeles, including deep foundation work on hillside sites throughout the greater Westside. All cost data reflects competitive bids from multiple qualified subcontractors on projects we have managed between 2024 and 2026.

1. WHY THIS PAGE EXISTS

Search for "foundation cost" online and you will find numbers like $5-$25 per square foot for residential foundations, or $3,500-$28,000 for foundation repair. Those numbers describe slab-on-grade work on flat lots in markets where the soil is predictable and the footings are 18 inches deep. They have nothing to do with a hillside project in Los Angeles where the structural engineer has specified 42-inch CIDH caissons drilled 60 feet to bedrock, tied together with grade beams supporting a multi-level retaining wall system, with the entire slope behind the house stabilized with soil nails and high-tensile mesh.

There is, as far as we can find, no useful public resource that documents what deep foundation work actually costs on residential hillside projects. The information exists - it lives in subcontractor proposals, bid leveling spreadsheets, and change order logs on projects managed by experienced construction managers. But it does not get published, partly because it is proprietary and partly because the numbers are complex enough that stripping them out of context risks being misleading.

This page attempts to fill that gap responsibly. Every cost below is drawn from competitive bids on projects we have managed - not from databases, not from national averages, not from cost-per-square-foot rules of thumb that collapse when applied to complex sites. We present ranges reflecting multiple qualified bidders, and we explain what drives the range so you can estimate where your project falls within it.

How to Use This Page
This page is organized around unit costs - cost per linear foot, cost per square foot, cost per cubic yard, cost per hour. Unit costs are scalable. An owner with a 2,500 SF hillside house needing three caissons can use these numbers just as effectively as someone building a 15,000 SF estate. Project-level totals appear only as validation that the unit rates produce real numbers when multiplied against actual scopes.

Two audiences will get the most from this page. First, owners in feasibility or active construction who received a foundation cost number that seems enormous and need to understand whether it is real and what is driving it. Second, architects doing early budgeting who need a reality check before design gets too far ahead of budget, and who want a credible resource to send clients when the foundation cost conversation happens. For broader context on how foundation systems are selected and designed, see our companion guide on foundation systems and geotechnical engineering.

Not every hillside project requires a multi-million-dollar foundation. A house on a moderate slope with a single retaining wall and a handful of caissons may have a total below-grade cost of $400K to $800K. The unit costs on this page are designed to be scalable: an owner can multiply their own pile count, wall area, and grading volume against these rates to develop a planning-level number for their specific site. The most complex projects - multiple retaining wall systems, deep piles across difficult geology, extensive slope stabilization - reach into the millions. But the majority of hillside residential projects in Los Angeles fall somewhere in between.

2. CONVENTIONAL FOUNDATIONS: THE BASELINE

Before getting into deep foundation costs, it helps to establish what conventional foundation work costs on a flat-lot residential project. These numbers set the baseline that makes hillside costs comprehensible - without them, the deep foundation numbers have no frame of reference.

The table below reflects bids from four to five concrete subcontractors on flat-lot residential projects in the greater Westside, collected in 2025. These are standard residential foundations: continuous footings, pad footings, slab-on-grade, and shear walls. Nothing exotic.

ComponentUnitCost RangeNotes
Continuous footing, 15"W x 18"DLF$100 - $150Thickened slab edge
Continuous footing, 24"W x 18-24"DLF$175 - $235Standard residential
Continuous footing, 30"W x 24"DLF$200 - $270Heavier loads
Continuous footing, 36"W x 18"DLF$280 - $380Wide residential
Continuous footing, 54"W x 24"DLF$450 - $600Heavy residential
Continuous footing, 84-114"WLF$550 - $750Widest residential footings
Pad footing, 3' SQ x 24"DEA$1,000 - $1,600Point loads
Pad footing, 4' SQ x 24"DEA$1,200 - $1,800Point loads
Pad footing, 5' SQ x 24"DEA$1,500 - $2,200Heavy point loads
Slab on grade, 5"SF$24 - $321,200-5,100 SF scopes
Thickened slab edge, 18"x18"LF$45 - $70At slab perimeter
Concrete shear wall, 12" thickSF of wall face$75 - $100Lateral resistance
Concrete shear wall, 14" thickSF of wall face$85 - $110Heavier lateral
Concrete shear wall, 15" thickSF of wall face$90 - $120Maximum residential
Elevated structural slab, 10" thickSF$50 - $65Includes shoring rental
Concrete headers/corbelsLF$175 - $250Steel-to-concrete transitions
Set steel template + drypackEA$150 - $250Per location
Concrete stairs on gradeEA per flight$3,000 - $6,000Formed and poured
Concrete curbs, 8-12" thickLF$25 - $45Site curbing
Mobilization (flat lot)EA$2,000 - $5,000Per mobilization
Project-Level Reference
On flat-lot residential projects with 2,200-5,100 SF of slab area and conventional footings, total foundation bids from four to five subcontractors have ranged from $150K-$350K per residence depending on scope. This is the cost universe where national average data is roughly relevant. The moment you move to a hillside site with deep foundations, these numbers stop applying.

These costs will look familiar to anyone who has built on a flat lot. The footing widths and depths are dictated by the structural engineer's load calculations, and the slab thickness is standard for residential construction. The cost range at each line reflects differences in subcontractor overhead structures, crew productivity assumptions, and how aggressively each bidder prices to win the work. For a broader view of construction costs across all project phases, see our guide on LA construction costs.

3. WHAT DRIVES THE NUMBER ON HILLSIDE SITES

A hillside foundation does not cost more than a flat-lot foundation because it uses fancier materials or because hillside subcontractors charge higher margins. It costs more because the structural and geotechnical conditions require fundamentally different systems - deeper elements, heavier reinforcing, more complex formwork, specialized equipment, and construction sequences dictated by soil behavior rather than production efficiency. Five variables drive the number, and understanding them is the difference between reading a bid total and actually understanding what you are paying for.

Pile Diameter

CIDH (Cast-in-Drilled-Hole) piles on residential hillside projects range from 18 inches to 42 inches in diameter. The diameter is set by the structural engineer based on the loads the pile must carry and the bearing capacity of the soil or rock at the tip. Diameter affects cost in three ways: the drill rig required gets larger and more expensive, the volume of concrete per linear foot increases geometrically (a 42-inch pile uses more than five times the concrete per foot as an 18-inch pile), and the steel reinforcing cage is heavier and harder to set. Moving from a 24-inch pile to a 42-inch pile roughly triples the installed cost per linear foot.

Pile Depth

Depth is dictated by the geotechnical investigation - the pile must reach bearing material, which on Los Angeles hillside sites can be anywhere from 12 feet to 65 feet or more below the surface. Deeper piles cost more not just because there is more drilling, concrete, and steel, but because deeper holes are more likely to encounter groundwater, caving soils, and obstructions that trigger time-and-materials billing. A pile that the geotechnical report says will be 35 feet deep may end up 50 feet deep if the bearing stratum is not where the borings predicted.

Pile Count

The number of piles is determined by the structural design. A simple hillside house might need 8-12 piles. A large project with multiple retaining wall systems, a pile-supported pool, and below-grade habitable space can require 30-50 piles or more. Pile count affects mobilization efficiency - a project with 40 piles will see lower per-pile costs because the drill rig and crew are on site for weeks rather than days. But more piles also means more opportunities for subsurface surprises to accumulate.

Soil and Rock Conditions

This is the variable that creates the widest cost uncertainty. Soil conditions determine whether the drill rig moves through material at a normal production rate or hits obstructions that slow drilling to a crawl. They determine whether the pile hole stays open long enough to set the steel cage and pour concrete, or whether casing is required at $7,000+ per hole. They determine whether groundwater is present and dewatering is needed. And they determine whether the geotechnical engineer requires drill-set-pour sequencing - meaning each hole must be drilled, caged, and poured the same day - which eliminates the efficiency of batch drilling. The geotechnical investigation provides the best available prediction, but it is based on a handful of borings across a site that may have highly variable subsurface conditions.

Site Access

Hillside sites in Los Angeles are frequently accessed by narrow, steep, winding roads that limit the size of equipment that can reach the site and the rate at which materials can be delivered or spoils exported. A drill rig that needs a level working platform requires the grading contractor to cut a bench into the slope before drilling can begin - and that bench may need to be rebuilt at a different elevation as pile work progresses across the site. Concrete delivery depends on pump trucks reaching the site and maintaining a continuous pour. Export of drill spoils requires haul trucks navigating streets that may have weight limits, turn restrictions, or neighbor-imposed hours of operation. Every one of these access constraints adds cost. For more on how hillside site conditions affect construction, see our guide on hillside construction in Los Angeles.

The Compounding Effect: These five variables do not add cost independently - they multiply. A project with large-diameter piles and deep bearing depths and difficult soil conditions and restricted access will cost far more than the sum of each variable applied separately. The worst-case scenario is a project where the geotechnical report underestimates depth, the soil conditions trigger casing and T&M drilling, and the site access constrains equipment size and concrete delivery rates simultaneously.

4. DEEP FOUNDATION UNIT COSTS: PILES

The table below is the core cost reference for CIDH pile work on hillside residential projects. These rates are drawn from three to five concrete subcontractor bids on projects in the greater Westside, collected between 2024 and 2026. "Installed cost" means the price includes drilling the hole, fabricating and setting the steel reinforcing cage, placing concrete, and staging drill spoils on site for later export.

Pile DiameterCost/LF (Installed)Concrete Vol/LFTypical DepthNotes
18" CIDH$120 - $200~0.13 CY12'-25'Temporary piles, light shoring
24" CIDH$150 - $280~0.23 CY15'-40'Most common residential pile
30" CIDH$220 - $380~0.36 CY20'-50'Heavier retaining walls
36" CIDH$300 - $500~0.51 CY25'-55'Major retaining wall systems
42" CIDH$400 - $650~0.69 CY30'-65'Maximum residential capacity
What Is Excluded: These installed rates exclude casing, tremie placement, dewatering, drill-set-pour sequencing, and additional footage beyond the contract depth. On many hillside sites, one or more of these exclusions will be triggered. Casing alone adds $2,500 mobilization plus $1,200 per hole plus $10 per foot per inch of diameter. A 24-inch cased pile at 30 feet adds roughly $7,200 per hole to the base cost. Budget 15-40% above the base installed rate to account for these standard exclusions.
Casing Cost Calculation
Formula: $2,500 mob + $1,200/hole + ($10/ft x diameter in inches x depth in feet)

Example: 24" pile, 30' deep
$2,500 + $1,200 + ($10 x 24 x 30) = $2,500 + $1,200 + $7,200 = $10,900 per hole

Note: The $2,500 mobilization is a one-time charge per project. Per-hole cost at this diameter and depth is approximately $8,400.

The concrete volume column matters because concrete is a significant component of the installed cost, and overbreak - where the hole diameter enlarges beyond the nominal size due to soil conditions - is billed as additional concrete. Standard contract provisions allow the subcontractor to bill for concrete exceeding 10% overbreak at $245-$275 per cubic yard plus pumping. On sites with soft or caving soils, overbreak can add 15-30% to the concrete volume.

A moderate hillside project requiring eight 24-inch piles at 25 feet average depth represents approximately 200 linear feet of drilling. At $150 to $280 per linear foot, the pile cost alone is $30K to $56K. Add grade beams, a single retaining wall, and grading, and the total below-grade scope for this type of project typically falls in the $350K to $700K range.

Concrete Material Costs

Concrete pricing varies by mix design, and the structural engineer's specifications will dictate which mix is required for each element. On deep foundation work, 6000 PSI is the standard structural mix for piles and grade beams, with 7000 PSI sometimes specified for heavily loaded elements.

Mix Design$/CY DeliveredNotes
4000 PSI$180 - $220Non-structural applications
6000 PSI$220 - $270Standard structural
7000 PSI$250 - $310High-strength elements
Upcharge 6000 to 7000 PSI$25 - $35/CYCommon field decision
Slurry$225/CY + pump/laborFor wet pile holes
Additional concrete (>10% overbreak)$245 - $275/CY + pumpStandard contract provision
Budget Tip: When estimating total concrete cost for a pile program, multiply the nominal volume (from the concrete volume per LF column above) by 1.15-1.30 to account for overbreak before applying the per-CY concrete price. On a 40-pile program at an average of 0.40 CY/LF and 40 feet average depth, that overbreak adjustment can represent $30K-$75K in additional concrete alone.

5. GRADE BEAMS, RETAINING WALLS, AND ASSOCIATED CONCRETE

Piles are only the starting point. The structural system that connects piles to each other and to the building above includes grade beams, retaining walls, lagging, and various concrete elements that together often cost as much as or more than the piles themselves. These costs are drawn from three to five concrete subcontractor bids on hillside projects we have managed. For a deeper discussion of retaining wall types and design considerations, see our guide on retaining walls in Los Angeles.

ComponentUnitCost RangeNotes
Grade beam (standard residential)LF$250 - $400Varies with cross-section and reinforcing
Grade beam (heavy, 36"+ deep)LF$400 - $600Major retaining wall systems
CIP/shotcrete retaining wall, 8" thickSF of wall face$70 - $95Low walls, light earth pressure
CIP/shotcrete retaining wall, 10-12" thickSF of wall face$80 - $120Standard hillside retaining
CIP/shotcrete retaining wall, 16" thickSF of wall face$100 - $150Heavy earth pressure
CIP/shotcrete retaining wall, 22" thickSF of wall face$130 - $200Maximum section
Concrete lagging (permanent, shotcrete)SF of face$30 - $60Between soldier piles, includes dowels
Epoxied rebar dowelsEA$20 - $30Connection between elements
Starter beam for lagging wallLF$85 - $12018"x18" at top of wall
Pile-supported pool shellLS$80K - $250KVaries with size and structure
Sub-slabs (with vapor barrier)SF$18 - $28Below-grade flatwork

The retaining wall costs above are per square foot of wall face, which is the standard measurement for pricing walls. To estimate a wall's cost, multiply the exposed height by the length to get the face area in square feet, then apply the rate for the appropriate thickness. Wall thickness is determined by the structural engineer based on the earth pressure and surcharge loads the wall must resist - thicker walls indicate more load, heavier reinforcing, and higher cost per square foot.

Retaining Wall Cost Example
Example: 80 LF retaining wall, 12' exposed height, 12" thick
80 LF x 12' = 960 SF of wall face
960 SF x $80-$120/SF = $76,800 - $115,200

Add grade beam at top: 80 LF x $250-$400/LF = $20,000 - $32,000
Add supporting piles (8 piles at 30" dia, 35' avg depth): 8 x 35 x $220-$380/LF = $61,600 - $106,400

Total system (wall + beam + piles): $158,400 - $253,600 for a single 80-foot wall line

A complex hillside project may have three to six separate retaining wall systems at different elevations, each with its own pile support. The aggregate cost of retaining wall systems - walls, grade beams, and their supporting piles combined - frequently exceeds the cost of the building's own foundation.

On a moderate hillside project, the retaining wall scope is often a single wall line - perhaps 60-100 linear feet at 8-12 feet of exposed height. That single system, including its supporting piles and grade beam, typically costs $120K to $250K. The cost calculation above illustrates how to build that number from unit rates. Projects with multiple wall systems stacking up a slope are where the retaining wall budget reaches into the hundreds of thousands or millions.

6. EARTHWORK AND GRADING UNIT COSTS

Earthwork on a hillside site is a fundamentally different operation than grading a flat lot. The work happens in stages coordinated with shoring and structural work, the material must often be exported rather than redistributed on site, and the equipment access limitations that affect all hillside work are most acute during grading when the largest equipment is needed. These rates reflect bids from qualified grading contractors on hillside projects we have managed, supplemented by general market data.

ComponentUnitCost RangeNotes
Mass excavation (accessible hillside)CY$20 - $35Equipment can reach, spoils staged on site
Mass excavation (restricted access)CY$35 - $55Steep terrain, limited equipment access
Below-grade excavation (staged with shoring)CY$45 - $75Excavated in lifts with shoring/soil nail work
Footing/trench excavationCY$30 - $50Sometimes included in concrete bid
Spoils export (structural, pile/footing work)CY$35 - $55Loaded, hauled, disposed; hillside haul routes
Spoils export (mass, site grading)CY$25 - $45Higher volume, somewhat more efficient
Haul truck (Super 10, 10 CY capacity)HR$110 - $155Standard for hillside haul routes
Structural backfill (compacted)CY$30 - $50Behind retaining walls, on-site material
Pea gravel backfill (air-pumped)CY$60 - $90Behind shoring walls per engineer spec
Import fillCY$35 - $55Delivered, placed, compacted
Subdrain (furnish + install)LF$35 - $60Continuous behind each wall line
Keyway excavation and backdrainLS per keyway$20K - $50KAt base of remedial slopes
Site drainage systemLS$75K - $200KDrain lines, catch basins, sump vault, discharge
LID compliance systemLS$75K - $100KPermavoid or equivalent
Erosion control (per rainy season)Season$25K - $40KFurnish, place, maintain, remove
Drill bench grading (for rig access)LS per bench$15K - $40KLevel working platform for drill rig
Stabilized construction entranceLS$15K - $20KRock plates, crushed material; haul route compliance
Earthwork Budget Rule of Thumb
On hillside sites with significant cut-and-fill requirements, the earthwork scope frequently approaches the structural concrete scope in total cost. If the concrete budget for piles, grade beams, and retaining walls is $500K, expect the earthwork budget to be in a similar range. This relationship holds across a wide range of project sizes because both scopes are driven by the same underlying site conditions.

On a moderate hillside project with 1,500 to 3,000 cubic yards of excavation and export, the earthwork and grading scope typically runs $75K to $200K - a fraction of the $2M+ earthwork costs associated with major hillside projects requiring tens of thousands of cubic yards of material movement. Most of the line items in the table above still apply to moderate projects, but the quantities are smaller and the access is often less constrained.

Two items on this table deserve special attention. Drill bench grading is the cost of creating a level working platform on a slope so the drill rig can operate safely. This is pure access cost - it does not produce any permanent work. On a site where pile locations span multiple elevations, the bench may need to be cut, used, backfilled, and recut at a different elevation multiple times. LID compliance (Low Impact Development) is a regulatory requirement under the Los Angeles permitting framework - the site must manage stormwater on-site through infiltration, capture, or treatment systems. The $75K-$100K range covers manufactured systems like Permavoid; custom-designed bioretention systems can cost more.

Haul Route Cost Tip: Spoils export is priced per cubic yard, but the real driver is haul time per load. A site accessed by a steep, narrow road with a 10-minute round trip to the staging area will see export costs at the high end of the range. A site with direct street access and a short run to the dump truck will price at the low end. Ask your grading contractor how many loads per day they are assuming - that single number explains most of the pricing variation on export.

7. SLOPE STABILIZATION UNIT COSTS

Slope stabilization is one of the most volatile cost elements on a hillside project. The scope is driven by the geotechnical engineer's assessment of slope stability, which is refined through design development as additional subsurface data becomes available. It is common for slope stabilization scope to increase 30-45% between the preliminary estimate and the final engineered design. The rates below come from a specialty drilling subcontractor, across three proposals on two plan revisions for a single project, supplemented by general market data.

ComponentUnitCost RangeNotes
Soil nail (drill, install, grout)LF of drilling$50 - $964" diameter; varies with length and conditions
Additional soil nails beyond contractLF$62 - $88Contract overrun rate
Drilled anchor (pinned mesh system)LF$138 - $15415'-20' anchors; includes all equipment and materials
Tecco net barrierSF of slope face$15 - $20High-tensile mesh, spike plates, rope anchors
Additional netting beyond contractSF$17 - $20Contract overrun rate
Combined system (nails + net, all-in)SF of slope face$45 - $55Total system cost per SF of stabilized slope
Shotcrete-faced soil nail wallSF of wall face$25 - $60Alternative to Tecco net
Shotcrete overbreak (above theoretical)CY$675Volume beyond plan quantity + 10%
Clear and grub (slope preparation)SF$4.50 - $6.00Vegetation removal before nail/mesh installation
Mobilization (specialty drilling, local)EA$5K - $15KPer mobilization, local contractors
Mobilization (specialty, out-of-state)EA$40K - $65KIncludes mob + demob, lodging, travel

The table above includes two distinct anchor systems. Standard soil nails at $50-$96 per linear foot are 4-inch diameter holes drilled into the slope, fitted with a steel bar, and grouted in place. This is the most common system on Los Angeles hillside residential projects and is typically installed by local specialty drilling contractors. Pinned mesh (drilled anchor) systems at $138-$154 per linear foot use a different installation approach with shorter, more closely spaced anchors and a high-tensile mesh pinned to the slope face. The higher per-foot rate reflects the anchor methodology and, in some cases, out-of-state specialty contractors whose pricing includes travel, lodging, and equipment transport. Both systems achieve the same objective - stabilizing the slope face - but the unit economics are different enough that the choice of system materially affects the budget.

Slope Stabilization Bid Spread
On a recent project, three specialty contractors bid the same slope stabilization scope. The apparent spread was nearly 40%. Two bidders used standard Tecco net with soil nails; the third used a pinned mesh anchor system with higher per-foot anchor costs but different mesh coverage. After normalizing to the same technical approach, the two comparable bids were within 8%. The lesson: bid leveling on slope stabilization work requires careful attention to the technical approach, not just the bottom line.
Design Development Adds Scope: Slope stabilization scope routinely increases 30-45% between the preliminary geotechnical recommendation and the final engineered design. This happens because preliminary estimates are based on limited boring data. As the engineer develops the design with additional subsurface information, nail counts increase, drilling footage grows, and mesh coverage expands. Treat any preliminary slope stabilization number as a starting point, not a budget.

The combined system rate of $45-$55 per square foot of slope face is the most useful number for early budgeting. Measure the slope area that the geotechnical engineer has flagged for stabilization, apply this rate, and add contingency. On a slope with 5,000 SF of face area, that produces a working estimate of $225K-$275K before contingency - a number that can double if design development adds area or the engineer specifies deeper or more closely spaced nails.

Slope Stabilization Quick Estimate
Formula: Slope face area (SF) x $45-$55/SF x 1.30 design development factor

Example: 5,000 SF slope face
5,000 x $50 = $250,000 base
$250,000 x 1.30 = $325,000 working budget

Note: The 1.30 factor accounts for the scope growth that typically occurs between the preliminary geotechnical recommendation and the final engineered design.

8. EQUIPMENT AND LABOR RATES

When deep foundation work moves to time-and-materials billing - and on most complex hillside projects, some portion of the work will - the cost is driven by equipment and labor rates. Understanding these rates lets you evaluate T&M invoices, estimate the cost of scope additions, and make informed decisions about change order negotiations. These rates are compiled from five to seven subcontractor proposals across multiple projects between 2024 and 2026.

Equipment Rates

EquipmentHourly RateMinimumNotes
Lo Drill Rig (CAT 120 class)$325 - $3958 hrLight residential
Mid-Range Drill Rig (Soilmec R208/R312)$430 - $5408 hrStandard hillside
Heavy Drill Rig (Soilmec R516)$480 - $6308 hrDeep/large piles
Heavy Drill Rig with CFA$580 - $7308 hrProduction drilling
KRUPP Drill Rig$3308 hrSpecialty applications
Drill Rig Oiler$55 - $65With rigAlways required with drill rig
Drill Rig Operator$125With rigSometimes bundled in rig rate
Mobile Crane, 40-75 ton$550 - $9508 hrCage setting, material handling
Mobile Crane, 90-150 ton$1,2508 hrHeavy lifts
Crane Support Truck$2558 hrRequired with crane
Concrete Pump$550 - $1,200 setup + $20/CYPer mobSetup plus volume charge
Tremie Pipe$2,500 - $4,000Per mobWhen water present in hole
Bobcat/Skid Steer$110 - $1904 hrSite support
Mini Excavator$110 - $1854 hrTight access work
Full-Size Excavator$230 - $2754 hrMass excavation
Excavator with Breaker$178 - $2304 hrRock or obstruction removal
Super 10 End Dump$110 - $155Per loadHaul truck
Air Compressor with attachments$950/dayPer dayPneumatic tools support

Labor Rates

All labor rates below are T&M billing rates including burden (taxes, insurance, benefits). These are what the subcontractor bills you, not what the worker takes home. Standard markup on T&M work is 10-15% overhead and profit on top of these rates.

ClassificationStraight TimeOT/SaturdayNotes
Superintendent/Supervisor$80 - $150$120 - $225Wide range reflects different overhead structures
Foreman$72 - $95$108 - $142On-site crew leadership
Leadman/Skilled$72 - $82$108 - $123Experienced trade worker
Carpenter/Iron Worker$55 - $67$83 - $101Formwork, rebar
Laborer$45 - $75$68 - $113Widest range across subcontractors
Equipment Operator$85 - $125$128 - $188Rig, crane, excavator
Welder$108 - $150$162 - $225Specialty; certified structural
Rate Variation Context
The wide ranges on some classifications - particularly Superintendent ($80-$150) and Laborer ($45-$75) - reflect differences in how subcontractors structure their overhead. Some build more burden into the labor rate and charge lower markup. Others keep rates lean and recover overhead through higher OH&P percentages. When comparing T&M bids, compare the total loaded cost (rate x hours x markup), not the hourly rates alone.

9. DRILLING CONDITIONS: WHERE THE CONTRACT ENDS AND T&M BEGINS

Every deep foundation subcontract includes a set of standard exclusions - conditions that, if encountered, take the affected work out of the lump-sum price and into time-and-materials billing. These exclusions are not buried in fine print; they are standard in the industry and present in every bid we have reviewed. Understanding them before you sign the contract is the difference between a budget surprise and a managed risk. For context on how contract structures work in construction management, see our guide on budget and cost control.

Drill-Set-Pour Sequencing

This is the single most impactful exclusion. Under normal drilling operations, the subcontractor drills multiple holes in sequence, then comes back to set steel cages and pour concrete. This is efficient because each task uses different equipment. Drill-set-pour sequencing means the geotechnical engineer requires that each hole be drilled, the cage set, and concrete placed on the same day - the hole cannot sit open overnight. This requirement is triggered when the geotechnical report identifies caving soils, high water table, or unstable hole conditions.

When drill-set-pour sequencing is required, the drill rig cannot move to the next hole until the current hole is fully poured. The crane must be on site for cage setting. The concrete pump must be standing by. The crew is larger. A day that might have produced four drilled holes under normal sequencing produces one or two completed piles instead. The cost difference is significant: a full production day under drill-set-pour sequencing runs $15,000-$25,000, and it is billed as T&M regardless of the lump-sum contract price.

Casing

Casing is a steel tube inserted into the pile hole to prevent the walls from collapsing during drilling and concrete placement. It is excluded from base bids because it is a response to soil conditions that may or may not be present across all pile locations. When required, casing adds $2,500 mobilization (one-time) plus $1,200 per hole plus $10 per foot per inch of diameter. On a project where half the piles need casing, this exclusion alone can add $100K-$200K to the foundation cost.

Obstruction Rates

Obstructions are defined as material that cannot be drilled at a rate of 1-2 feet per 5 minutes. When the drill rig hits an obstruction - rock, old foundations, cemented soils, boulders - the work shifts to T&M at $450-$750 per hour. An obstruction that takes four hours to drill through costs $1,800-$3,000 on a single pile. Multiply that across 30-40 piles and the exposure is real.

Other Standard Exclusions

  • Dewatering: Must be provided by others. If groundwater is present, the owner or GC is responsible for dewatering the pile holes before concrete can be placed. Dewatering pump setups run $5K-$15K per mobilization plus ongoing pumping costs.
  • Additional footage: Billed at the contract $/LF rate per pile diameter. If the geotechnical engineer calls for a pile to go deeper than the contract depth, the additional footage is billed at the same per-linear-foot rate specified in the contract for that diameter.
  • Hard rock / caving conditions: Shifts to T&M at obstruction rates. Any condition that reduces drilling production below the assumed rate triggers the contractual hourly rate rather than the per-linear-foot rate.
  • Tremie placement: Required when water is present in the hole and cannot be dewatered. Tremie pipe mobilization runs $2,500-$4,000 per mobilization. Concrete placed by tremie is slower and uses more material (slurry displacement).
The Takeaway on Exclusions
Every exclusion listed above is a known risk, not a surprise. They appear in every deep foundation bid. The question is not whether you will encounter them - it is how many piles they will affect. A thorough geotechnical investigation with borings at or near pile locations reduces the uncertainty. But even the best geotechnical report cannot eliminate it. Budget 15-25% above the lump-sum bid to cover exclusion-triggered costs.

10. WHY BIDS DIVERGE

If you receive three bids for deep foundation work and the totals are $2.2M, $2.25M, and $2.55M, your first instinct may be that the high bidder is expensive and the low bidder is the best value. That instinct is almost always wrong. Wide apparent spreads on deep foundation bids are common, but most of the variance comes from scope differences rather than real pricing differences. Bid leveling - the process of normalizing bids to a common scope - is one of the most valuable functions a construction manager performs. For a broader discussion of how delivery methods affect bid analysis, see our guide on construction contracts.

Concrete Bid Example

On a hillside project we managed, three qualified concrete subcontractors bid the same pile and retaining wall scope. The raw totals were approximately $2.23M, $2.24M, and $2.55M - an apparent spread of about $300K or 14%. After scope normalization, the picture changed significantly. One bidder had included roughly $146K of flatwork that the others excluded. Another had included approximately $177K of slope stabilization that the others either excluded or priced as a separate line item. Grade beam pricing was bundled differently by all three. After normalizing to a common scope, the real pricing spread was approximately $100K - about 4-5% between the three bidders.

Flat-Lot Example

Even on simpler projects, bid divergence can be misleading. On a flat-lot residential foundation, four subcontractors bid the same scope. Raw totals: $167K, $175K, $253K, and $295K - an apparent spread of 77%. One bidder had included a water feature valued at roughly $56K that the others excluded entirely. After normalization, the real spread was approximately 20%. Still meaningful, but a fraction of what the raw numbers suggested.

Earthwork Example

Two grading contractors bid the same hillside earthwork scope. Their totals were $2.14M and $2.24M - within 5% of each other and suggesting a straightforward comparison. But the internal allocations told a different story. Below-grade excavation was priced at $275K by one bidder and $547K by the other. Spoils export was bundled into the grading line item by one and broken out at $450K by the other. The totals were close, but the risk profiles were completely different depending on which scope elements actually materialized at the assumed quantities.

Slope Stabilization Example

Three specialty contractors bid the same hillside slope stabilization scope. The apparent spread was nearly 40%. After analysis, the spread was driven primarily by different technical approaches, not pure pricing differences. Two bidders used standard soil nails with Tecco net; the third used a drilled anchor pinned mesh system with higher per-foot costs ($138-$154/LF vs. $61-$79/LF) but a different mesh specification. The mesh coverage also varied significantly between bidders for what all three described as the same plan set. After normalizing to the same technical approach, the two comparable bids were within 8%.

The Bid Leveling Lesson: Never award a deep foundation contract based on raw bid totals. The scope inclusions and exclusions across bidders vary so much that the lowest total is often not the lowest real price. A qualified construction manager will normalize bids to a common scope, identify the actual pricing spread, and evaluate which bidder's assumptions about conditions and quantities carry the least risk. This analysis typically takes 20-40 hours of detailed work and saves multiples of that cost in avoided change orders.

11. HOW BUDGETS EVOLVE

Deep foundation budgets do not hold still from feasibility through construction. They move - sometimes significantly - as the design develops, the geotechnical understanding improves, and field conditions reveal what the borings could not. Understanding why budgets evolve, and in which direction, helps owners and architects set realistic expectations and make informed decisions about contingency. For a comprehensive look at how construction budgets develop, see our guide on budget and cost control.

Design Development Drives Scope

On one project we managed, the structural concrete scope was originally budgeted at approximately $3.6M including contingency during early design. Eighteen months later, after the design had been phased and repriced against developed structural drawings, the scope was broken into site work at approximately $1.5M and house foundation at approximately $1.26M. The total was in the same range, but the allocation was completely different - and that allocation matters because different elements carry different risk profiles.

Slope stabilization scope is particularly prone to growth during design development. It is common for the final engineered design to include 30-45% more drilling footage and mesh area than the preliminary estimate, simply because the geotechnical engineer refines the design as subsurface data improves. This growth happens before any field conditions are encountered. It is a function of engineering thoroughness, not surprises.

Budget Evolution Pattern
Deep foundation budgets typically evolve through three phases:

Feasibility (ROM): Unit cost x estimated quantity, plus 25-35% contingency. This is the number used to evaluate whether the project is financially viable.

Design Development: Updated quantities from structural drawings, repriced against current bids. Contingency tightens to 15-25%. This is when slope stabilization scope typically increases 30-45%.

Construction: Lump-sum contracts with defined exclusions. Contingency covers exclusion triggers and field conditions. Final cost depends on how many exclusions are triggered during drilling.

Field Conditions Drive Change

Even after design is complete and contracts are signed, below-grade work is uniquely exposed to conditions that cannot be fully known in advance. The geotechnical report is based on a limited number of borings that sample a fraction of the subsurface. Between borings, the soil profile is interpolated - and those interpolations can be wrong. A pile specified at 35 feet may need to go to 50 feet. A hole expected to stand open may cave and require casing. A bearing stratum that appeared continuous in the borings may be absent at certain pile locations.

None of this is unusual or indicative of poor engineering. It is the nature of building on hillside sites where the subsurface is complex and variable. The appropriate response is not to demand a fixed price that pushes this risk onto the subcontractor (who will simply add a premium for the risk transfer) but to budget adequate contingency and manage the risk actively through field verification and real-time decision-making. This is one of the core functions of pre-construction management in a CMAR delivery structure.

12. T&M WORK ON DEEP FOUNDATIONS

Time-and-materials work on deep foundation projects is not a sign that something has gone wrong. On most complex hillside projects, some portion of the pile work will transition to T&M when drilling conditions trigger contract exclusions. Understanding the daily cost structure helps you budget for this exposure and evaluate T&M invoices as they come in.

The data below is drawn from verified daily logs on a hillside project where seven days of T&M work totaled approximately $121K before the 15% overhead and profit markup. That markup is standard and reflects the subcontractor's cost of managing T&M operations, which require more supervisory time and documentation than lump-sum work.

Day TypeTypical EquipmentTypical CrewConcreteDaily Cost
Light (drill only)Rig + oiler, 8 hrsRig crew onlyNone$4,000 - $6,000
Medium (drill + set)Rig + oiler + crane, 7-12 hrs2 laborersNone or partial$10,000 - $17,000
Full productionRig + oiler + crane + pump, 8-14 hrs6 laborers + foreman70-90 CY$15,000 - $25,000
T&M Budget Planning: On most hillside projects, a few days of T&M work during the pile program is normal. The daily cost table above lets you estimate the exposure: multiply the expected day type by the number of days your geotechnical consultant considers likely based on the boring data. A project with favorable soil conditions may see one or two T&M days total. A project with variable subsurface conditions may see a week or more. The 15-25% contingency on the lump-sum bid is designed to cover this range.

The three day types reflect the reality of how T&M work unfolds. A light day is typically exploratory drilling or working through obstructions where no concrete is placed. A medium day involves drilling and setting one or two cages, with the crane on site but concrete delivery limited. A full production day under T&M occurs when drill-set-pour sequencing is in effect and the full spread of equipment and crew is on site completing piles from start to finish. The cost difference between these day types is driven primarily by equipment and crew size, not by the amount of permanent work completed.

Invoice Verification Tip: On T&M days, require the subcontractor to submit daily logs documenting equipment on site (with hours), crew by classification (with hours), concrete delivered (with tickets), and a narrative of work completed. Review these logs daily, not at the end of the month. Discrepancies are much easier to resolve when the work is fresh. A construction manager reviews and approves T&M logs as part of standard field operations.

13. WHAT A REALISTIC BELOW-GRADE BUDGET LOOKS LIKE

The unit costs in the preceding sections are the building blocks. This section assembles them into project-level budgets across three tiers - conventional, moderate hillside, and complex hillside. Most residential hillside projects in Los Angeles fall into the moderate category, not the complex one. The table below is designed so that a reader can identify which tier their project falls into based on the conditions column, then use the unit costs from earlier sections to refine the number for their specific scope.

Project TypeExample ConditionsBelow-Grade Cost RangeTypical % of Total Construction Cost
Conventional (flat to moderate slope)Spread footings, slab-on-grade, pad footings, no piles, no significant retaining$200K - $500K8-15%
Moderate hillsideSingle retaining wall line, 6-15 CIDH piles at moderate depth, standard grading with some export, no slope stabilization$350K - $1.2M15-25%
Complex hillsideMultiple retaining wall systems, 20-50+ deep piles, significant shoring, slope stabilization, below-grade spaces, major earthwork and export$1.5M - $5M+30-55%

The "Typical % of Total Construction Cost" column provides another way to gut-check a below-grade number. On a $5M total construction budget for a moderate hillside project, a below-grade cost of $750K to $1.25M (15-25%) is in the expected range. If the below-grade number is coming in at 40% of total construction cost and the project does not have the conditions described in the complex tier, something in the scope or pricing deserves a closer look.

What Each Tier Looks Like in Practice

Conventional ($200K-$500K): This is a flat-lot or gentle-slope project with standard spread footings, slab-on-grade, and perhaps a few pad footings for point loads. No piles, no significant retaining walls, no slope stabilization. The foundation is straightforward concrete work priced from the conventional foundation table in Section 2. Most of the cost is in footings and slab.

Moderate hillside ($350K-$1.2M): This is the most common hillside residential project in Los Angeles - a house on a slope that requires a single retaining wall, 6-15 CIDH piles at moderate depth (20-35 feet), standard grading with 1,500-3,000 cubic yards of cut and export, and no slope stabilization. The piles might cost $30K-$120K, the retaining wall system (wall + grade beam + supporting piles) $120K-$250K, and the earthwork $75K-$200K, with the remainder covering drainage, LID, and contingency. This is the tier where most readers of this page will find their project.

Complex hillside ($1.5M-$5M+): This is a project with multiple retaining wall systems at different elevations, 20-50+ piles across multiple diameters and depths, slope stabilization with soil nails and netting, below-grade habitable space, and major earthwork requiring tens of thousands of cubic yards of material movement. The below-grade budget on these projects can exceed the cost of the above-grade structure. These projects are real and they exist throughout the greater Westside, but they are not the majority of hillside residential work.

Finding Your Project in These Numbers
The unit costs in Sections 4 through 8 are the same regardless of which tier your project falls into - a linear foot of 24-inch pile costs $150-$280 whether you are drilling 8 piles or 40. The difference between tiers is quantity, not unit price. To build your own planning-level estimate: count your piles and multiply by depth and the per-LF rate for your diameter. Measure your retaining wall area and apply the per-SF rate. Estimate your earthwork volume and apply the per-CY rate. Add drainage, LID, and 15-25% contingency. The result will tell you which tier your project belongs to - and whether the bid you received is in the right range.

For a comprehensive discussion of overall construction costs across all phases - not just below-grade work - see our guide on LA construction costs.

14. PRE-CONSTRUCTION'S ROLE

Everything on this page - the unit costs, the exclusions, the bid divergence, the budget evolution - points to the same conclusion: deep foundation work on hillside sites requires professional management from before the first bid is solicited through the last pour. This is not a scope where choosing the lowest bidder and hoping for the best produces good outcomes. It is a scope where the decisions made during pre-construction directly determine whether the final cost lands at the low end or the high end of the range. For an overview of how a construction manager at risk handles this process, see our CMAR guide.

Geotechnical Investigation

The quality of the geotechnical investigation determines the quality of every cost estimate that follows. A report based on three borings across a hillside site provides a rough picture. A report with borings at or near each planned pile location provides a detailed one. The incremental cost of additional borings - typically $2,000-$5,000 per boring - is trivial compared to the cost of encountering unexpected conditions during drilling. A construction manager evaluates the geotechnical scope and recommends additional investigation where the risk of subsurface variability justifies the cost.

Bid Leveling

As the bid divergence examples in Section 10 illustrate, raw bid totals on deep foundation work are unreliable indicators of relative value. Bid leveling - the process of normalizing bids to a common scope, identifying inclusions and exclusions, and evaluating the assumptions behind each bidder's pricing - is essential. This analysis requires detailed knowledge of what each line item covers, how different bidders bundle or unbundle their scopes, and where the risk lies in each bidder's approach. It typically takes 20-40 hours of detailed work on a complex hillside foundation package.

Contract Structure

Deep foundation contracts need clear definitions of what is included in the lump sum, what triggers T&M, and what the T&M rates are. The standard exclusions discussed in Section 9 - drill-set-pour sequencing, casing, obstructions, additional footage - should each have a defined billing mechanism in the contract. The construction manager negotiates these provisions before the contract is signed, not when the first obstruction is encountered. For the broader context of how CMAR delivery structures these relationships, see our guide.

Field Verification

During construction, the construction manager's role shifts from estimating to verifying. Every T&M day requires documentation: equipment on site with hours, crew by classification with hours, concrete tickets, and a narrative of conditions encountered. This documentation is reviewed daily, not compiled at invoice time. The construction manager also coordinates between the drill subcontractor, the geotechnical engineer (who must inspect each pile hole before concrete is placed), the structural engineer, and the grading contractor whose work is sequenced around the pile program. For a complete picture of how construction timelines work on these projects, see our guide on construction timelines in Los Angeles.

Deep Foundation Pre-Construction Sequence
1. Geotechnical Investigation
2. Structural Design
3. Bid Package Development
4. Competitive Bidding
5. Bid Leveling
6. Contract Negotiation
7. Field Verification Plan

The pre-construction investment on a complex hillside foundation - the geotechnical investigation, the bid process, the contract negotiation, the field verification planning - typically represents 3-5% of the below-grade budget. On a $2.5M below-grade scope, that is $75K-$125K. The return on that investment is measured in avoided change orders, accurate contingency allocation, and a final cost that falls within the established budget range rather than blowing through it.

15. FREQUENTLY ASKED QUESTIONS

How much does a deep foundation cost on a hillside project in Los Angeles?
Below-grade costs on hillside residential projects in Los Angeles range from $350K to $1.2M for moderate hillside projects with a single retaining wall and 6-15 piles, up to $1.5M to $5M or more for complex projects with multiple retaining wall systems, 20-50+ deep piles, and slope stabilization. Most hillside residential projects fall in the moderate range. The cost depends on pile count, depth, retaining wall area, earthwork volume, and site access.
What does a CIDH caisson pile cost per linear foot?
Installed cost for CIDH piles ranges from $120-$200 per linear foot for 18-inch diameter piles up to $400-$650 per linear foot for 42-inch diameter piles. These rates include drilling, steel reinforcing cage, concrete, and spoils staging. They exclude casing, tremie, dewatering, and drill-set-pour sequencing, which can add 15-40% to the base cost.
Why is my hillside foundation so much more expensive than a flat-lot foundation?
A conventional flat-lot foundation with slab-on-grade and continuous footings typically costs $150K-$350K. A hillside foundation with CIDH piles, grade beams, retaining walls, and slope stabilization costs 5 to 15 times more because every element is structurally heavier, deeper, and harder to access. Drill rigs need level benches cut into slopes. Concrete is pumped rather than poured directly. Spoils must be exported on haul routes. The soil conditions themselves add cost through casing, dewatering, and obstruction drilling.
What is drill-set-pour sequencing and why does it cost extra?
Drill-set-pour sequencing means the geotechnical engineer requires that each pile hole be drilled, the steel cage set, and concrete placed on the same day. The hole cannot sit open overnight. This is standard on hillside sites with caving soils or high water tables. It is excluded from every base bid because it locks the drill rig into a pace dictated by concrete delivery and cage-setting logistics rather than pure drilling efficiency. When triggered, it typically converts the affected days to time-and-materials billing at $15,000-$25,000 per day.
How much contingency should I carry on a deep foundation budget?
For a hillside project with deep foundations, carry 15-25% contingency on the total below-grade budget. Slope stabilization may need additional contingency because the scope routinely grows during design development as the geotechnical engineer refines the nail layout. The contingency is not padding. It reflects the reality that subsurface conditions are never fully known until you start drilling, and structural engineering evolves as geotechnical data improves.
Why do foundation bids from different subcontractors vary so much?
Wide apparent bid spreads are common on deep foundation work, but most of the variance comes from scope differences rather than real pricing differences. One bidder includes flatwork another excludes. One bundles slope stabilization into the concrete bid while another prices it separately. One includes a water feature others leave out. After scope normalization during bid leveling, the real pricing spread on qualified bidders is typically 10-20%.
What is the difference between a conventional foundation and a deep foundation?
A conventional foundation uses spread footings and slab-on-grade that bear on soil near the surface. A deep foundation uses CIDH (Cast-in-Drilled-Hole) piles that extend down to bedrock or a bearing stratum, sometimes 30 to 60 feet below grade. Deep foundations are required on hillside sites where the surface soils cannot support the structural loads, where retaining walls need pile support, or where the building straddles a slope and must be anchored to competent material at depth.
How do I estimate deep foundation costs for my specific project?
Count your piles from the structural drawings, multiply each by its depth and the per-linear-foot rate for that diameter. Measure your retaining wall face area and apply the per-square-foot rate for the wall thickness. Estimate your earthwork volume in cubic yards and apply the excavation and export rates. Add drainage, LID compliance, and 15-25% contingency. The unit cost tables on this page are designed for exactly this kind of planning-level math.
What does a geotechnical investigation cost, and is it worth it?
A geotechnical investigation for a hillside residential project typically costs $15,000 to $40,000 depending on the number of borings and the complexity of the site. Additional borings at or near planned pile locations cost $2,000 to $5,000 each. This investment is small relative to a below-grade budget that may run $350K to $2M or more. The quality of the geotechnical data directly determines the accuracy of every cost estimate that follows.
What is the difference between a retaining wall and a shoring wall?
A retaining wall is a permanent structural element designed to hold back earth for the life of the building. A shoring wall is a temporary system that supports earth during construction, typically removed or abandoned after permanent walls are built. Both use similar construction methods (piles, lagging, shotcrete), but shoring walls are designed for shorter service life and different load conditions. Many hillside projects require both: temporary shoring to allow excavation, followed by permanent retaining walls as part of the finished structure.

If you are evaluating a deep foundation scope on a hillside site or trying to make sense of bids you have already received, we can help.

Tell Us About Your Project   |   How Our Engagements Work

The information on this page is provided for educational purposes and reflects the professional experience and perspective of Benson Construction Group. Cost ranges, timelines, and regulatory references reflect current conditions for the greater Los Angeles area and may vary based on project-specific conditions, site complexity, regulatory requirements, and market fluctuations. Building codes and incentive programs are subject to change. Verify current requirements with LADBS and program administrators before making project decisions. This content does not constitute professional advice for any specific project. Consult qualified professionals for project-specific guidance.