Skip to content
EMAE & Sons Inc
Quote
Menu

Project · Brentwood hillside

Hillside excavation and
deep foundations,
Brentwood

Civil & Structural

Overview

A custom home built into a hillside in Brentwood, under one contract from the demolition of the house that stood on the lot through to the structure below ground. The slope was cut and the rock in it broken out and exported, the excavation was held under cover and sandbag through the winter, caissons were drilled and grade beams poured, and the basement and pool walls were formed, poured, stripped, waterproofed and drained. The job is under construction.

Location
Brentwood, Los Angeles
Client
Private residential
Setting
Hillside lot, existing residence
Photographed
October 2025 – July 2026
Status
Under construction

Scope of work

  • Demolition of the existing single-story house and haul-off
  • Tree removal and site clearance by a licensed tree contractor
  • Perimeter silt fence, fiber roll and gravel bag controls
  • Hillside excavation, rock breaking and export by truck
  • Slope held under sheet cover and sandbag through the wet season
  • Caissons drilled by a specialist drilling contractor
  • Grade beams formed and poured to the structural drawings
  • Basement and pool walls formed, reinforced and poured
  • Wall waterproofing, drainage board and perimeter drain
  • Structural slab and continuing works

Site challenge and execution

Excavation into rock, held open through the winter

The building footprint was cut into a hillside of rock, and the face of that cut stands above the working platform for the full depth of the basement and pool below. Material came out in stages, and the face was left standing between them.

The sequence was therefore built around the wet season. The excavation was opened in October and the structure below ground was not closed until the following spring, so the open face stood through the winter under cover: sheeted end to end, weighted on a grid of sandbags, and held at the toe and along the boundary with fiber roll and silt fence behind a screened fence.

Export ran throughout and left by truck. Rock was broken down to a size a bucket could load before it went out, the working surface was wetted while machines were on it, and the roadway was swept between loads.

Sequence of work

Site protection preceded demolition. Fiber roll, silt fence and gravel bags were run along the full perimeter behind a screened fence, and tree removal was carried out by a licensed tree contractor before the machines came onto the lot.

The house on the lot was then demolished and the debris loaded directly into bins as it came down, with dust suppressed by hose while the machine worked. Excavation followed, and the rock in the cut was broken out, loaded and exported.

The excavation was closed down for the wet season under cover and sandbag. Caissons were drilled by a specialist drilling contractor, grade beams were cut between them, reinforced and poured, and the basement and pool walls were then formed, reinforced, sleeved for services and placed in lifts. The walls were stripped, waterproofed and faced with drainage board, a perimeter drain was run in gravel outside the footing, and the structural slab followed.

How the job ran

  1. Existing conditions

    15 October 2025

    The lot stood wooded, with mature trees and a stepped path running up the slope, and the surveyor's marks already set. A benchmark lath carries the site elevation.

    The undisturbed Brentwood hillside before work started, a steep wooded slope with mature trees and a stepped timber path running up it
    The slope as found
    Two surveyor's laths flagged in orange ribbon set into the undergrowth on the hillside, one hand-marked BENCHMARK and the other with its elevation
    The surveyed benchmark and its elevation, set before the first cut

  2. Site protection and clearance

    From 20 October 2025

    Fiber roll and silt fence were run along the full perimeter behind a screened site fence, and gravel bags were stockpiled on site. All of it was in place before the first excavation. Tree removal was carried out by a licensed tree contractor.

    Fiber roll and silt fence pinned along the full length of the site perimeter on the Brentwood hillside, weighted with gravel bags behind a screened construction fence
    Perimeter fiber roll and silt fence, run before the first excavation
    The screened site fence running along the boundary of the Brentwood hillside lot with fiber roll and gravel bags set continuously against its base
    Screened fence, fiber roll and gravel bags along the boundary

  3. Demolition and haul-off

    20–27 October 2025

    The single-story house on the lot was stripped and taken down, and the debris was loaded straight into roll-off bins standing alongside. Dust was suppressed by hose throughout, and the chimney was the last element left standing.

    A tracked excavator taking down the wall of a single-story stucco house on the Brentwood lot, with a roll-off bin alongside and broken timber across the ground
    The existing house taken down to the slab
    An excavator loading demolition timber directly into a roll-off bin on the Brentwood site, the remaining half of the house still standing behind it
    Debris loaded straight into the bin rather than stockpiled
    A crew member in a hi-vis vest running a hose across the demolition area on the Brentwood site to suppress dust, with a roll-off bin and the part-demolished house behind
    Dust suppressed by hose while the machine worked
    The brick chimney of the demolished house standing alone against the sky on the Brentwood lot, with the rest of the structure already down
    The chimney, last element standing

  4. Rock excavation and export

    27 October – 7 November 2025

    The material in the cut is rock, and it was broken down before it could be loaded. A hydraulic breaker and a grapple worked the face, the broken material was loaded to truck for export, and the working surface was kept wet while machines were on it.

    A Caterpillar 305 mini excavator cutting into the rock face of the Brentwood hillside, the bucket in the cut and broken material banked behind it
    Cutting the footprint into the rock face
    Broken rock stacked across the excavated Brentwood hillside platform in pieces up to boulder size, with an excavator working the face beyond
    Rock broken down to a size a bucket could load
    A compact track loader working the excavated surface on the Brentwood site under a spray of water, with a tracked excavator alongside it
    The surface wetted while machines worked it

  5. Storm-water protection

    12 November – 24 November 2025

    The excavation was closed down for the wet season. Sheet cover was drawn across the whole slope and weighted on a grid of sandbags, with fiber roll and silt fence held continuously along the toe and the perimeter.

    The entire excavated slope on the Brentwood site drawn over with gray sheet cover and weighted down on a regular grid of white sandbags
    The full slope sheeted and weighted on a sandbag grid
    Crew drawing sheet cover across the excavated platform on the Brentwood hillside, the edge of the sheet pinned along the graded surface
    Cover drawn out across the platform
    The cut face of the Brentwood hillside excavation standing unsupported above the working platform, its toe lined with sandbags
    The cut face held at the toe

  6. Caissons and grade beams

    12 December 2025 – 9 February 2026

    Caissons were drilled by a specialist drilling contractor using a tracked mast rig with a rock auger. Grade beams were then cut between them, reinforced to the structural drawings and poured by boom pump.

    A tracked mast drilling rig set up on the Brentwood hillside platform to drill caissons, with the cut face and screened perimeter fence behind it
    The caisson rig on the platform
    The rock auger of the drilling rig lowered towards a drilled caisson hole on the Brentwood site, its carbide teeth and flights in close view against the cut face
    Rock auger over a drilled caisson
    Grade beam trenches cut into the rock across the Brentwood platform with reinforcing steel and dowels set in the bottom of each run and timber laid across them
    Reinforcement set in the grade beam runs
    A concrete boom pump reaching over the excavated Brentwood platform to place the grade beams, the formed runs taped off below it
    The grade beams placed by boom pump

  7. Basement and pool walls

    25 February – 24 March 2026

    The structure below ground was formed in timber against the cut, reinforced through its full height and poured in lifts. Service penetrations were sleeved through the reinforcement before the forms were closed.

    Timber wall forms standing the full depth of the Brentwood basement excavation, braced and laddered, running the length of the cut face
    Wall forms standing against the cut
    Crew setting and bracing the timber basement wall forms on the Brentwood site, walers and kickers run along the outside of the form face
    Forms braced and set to line
    Vertical and horizontal reinforcing steel tied through the full height of the Brentwood basement wall, seen from inside the formed box against the sky
    Reinforcement tied through the full wall height
    Service sleeves run through the reinforcing cage at a corner of the Brentwood basement wall before the forms were closed, with dowels lapped through the junction
    Services sleeved through the cage before the forms closed
    A crew member working a concrete vibrator down the face of the closed basement wall forms on the Brentwood site, form ties and cones visible along the panel
    The wall placed and vibrated in lifts

  8. Waterproofing, drainage and slab

    21 April – 9 July 2026

    The walls were stripped, waterproofed and faced with drainage board, and a drain was run in gravel along the outside of the footing before backfill. The structural slab followed. Work on site is continuing.

    The stripped concrete basement and pool structure on the Brentwood site with its external face covered in black waterproofing membrane and drainage board, wall dowels standing above the pour line
    Walls stripped, waterproofed and faced with drainage board
    A drainage trench excavated along the outside of the waterproofed Brentwood basement wall, the membrane and its termination bar running the full length above it
    The perimeter drain run outside the footing
    The structural slab down over the Brentwood basement structure, waterproofing strips laid across the deck and reinforcing steel stacked ready at the edge
    The structural slab over the basement

Services on this project

Questions about work like this

Does EMAE & Sons build on hillside lots?

Yes. EMAE & Sons Inc carries out hillside excavation, deep foundations and structural concrete on sloping sites in Los Angeles and Ventura counties. On a custom home in Brentwood the firm demolished the existing house, cut the building footprint into rock, and formed and poured the basement and pool structure below ground, with the caissons drilled by a specialist drilling contractor. The firm holds California license #1107216, Class A General Engineering, Class B General Building and C-36.

Why does a hillside foundation need drilled piles?

EMAE & Sons Inc uses drilled piles on hillside foundations where the ground near the surface will not carry the structure, and has them drilled by a specialist drilling contractor. A drilled pile is bored below the surface material so the load is carried lower down, with grade beams spanning between the piles to support the structure above. On a hillside home in Brentwood the firm had caissons drilled and poured the grade beams between them.

How is a basement wall waterproofed and drained?

EMAE & Sons Inc waterproofs a basement wall on its outside face once the forms are stripped, then covers the membrane with drainage board and runs a perimeter drain in gravel along the outside of the footing before backfilling. Water reaching the wall is carried down the board to the drain rather than standing against the concrete. The firm built a basement and pool structure this way on a hillside home in Brentwood.

What erosion control is needed on a hillside site before the rainy season?

EMAE & Sons Inc closes a hillside excavation down for the wet season by sheeting the exposed face end to end and weighting the cover on a grid of sandbags, then holding the toe and the site perimeter with fiber roll and silt fence behind a screened fence. On a Brentwood hillside home the firm kept the cut under cover from November until the structure closed in the spring.

Send us the scope

EMAE & Sons Inc holds California license #1107216, Class A, B and C-36. Tell us what the site is and we will tell you what it needs.

Request a quote(805) 341-6683

All projects →