Project Overview
Location: Pacific Palisades, Los Angeles
Project Type: Below-grade basement waterproofing
Structure: Multi-level residential basement built into a hillside
System Used: Voltex bentonite waterproofing membrane
A luxury residential project in Pacific Palisades required a reliable below-grade waterproofing system to protect a multi-level basement structure constructed directly into the hillside.
This project was completed in Pacific Palisades, one of the hillside communities in Los Angeles where basement waterproofing systems must withstand significant hydrostatic pressure and groundwater movement.
Homes built in hillside neighborhoods throughout Los Angeles — including Pacific Palisades, Bel Air, Beverly Hills, and West Hollywood — often feature deep basements partially or fully below grade. These conditions expose the structure to groundwater migration, hydrostatic pressure, and soil movement that can compromise the integrity of the building if not properly waterproofed.
Below-Grade Basement Waterproofing in Pacific Palisades Hillside Homes
Surfacing and Waterproofing was brought in during the construction phase to design and install a durable waterproofing system capable of protecting the basement structure long-term.
The Challenge
The basement structure was positioned directly against hillside soil conditions, creating several critical waterproofing risks.
Primary challenges included:
• Continuous hydrostatic pressure from groundwater moving through hillside soil
• Multiple construction joints and cold joints between foundation pours
• Limited exterior access once the basement walls were backfilled
• Long-term risk of water intrusion into finished basement living areas
Because the foundation walls would be completely backfilled after installation, the waterproofing system needed to perform reliably without future access for exterior repairs.
The system therefore needed to provide:
• long-term resistance to hydrostatic pressure
• reliable sealing around penetrations and construction joints
• the ability to self-seal minor cracks that may develop in concrete over time.
The Waterproofing Solution: Voltex Bentonite System
After evaluating the site conditions and structural design, a bentonite-based waterproofing system was selected.
The project utilized Voltex, a sodium bentonite waterproofing membrane specifically engineered for below-grade structures.
Voltex consists of natural sodium bentonite clay encapsulated between geotextile layers. When exposed to water, the bentonite expands and forms a dense waterproof barrier that blocks water migration.
This self-sealing property makes bentonite membranes particularly effective in demanding below-grade environments where hydrostatic pressure is present.
Typical applications include:
• basement waterproofing systems
• below-grade foundation walls
• retaining walls in hillside construction
• underground parking structures.
Installation Process
Surface Preparation
Before installation, the structural concrete surfaces were carefully inspected and prepared to ensure proper contact between the waterproofing membrane and the structure.
Preparation included:
• removal of debris and sharp projections
• repair of voids or honeycombing in the concrete
• preparation of construction joints and structural transitions.
Proper surface preparation is critical in below-grade waterproofing systems because irregularities in the substrate can compromise membrane performance.
Membrane Installation
Voltex sheets were installed directly against the structural foundation walls, creating a continuous waterproofing barrier.
Key installation procedures included:
• overlapping membrane seams to maintain waterproof continuity
• mechanically securing the membrane before backfilling
• sealing all penetrations, tie-backs, and transitions.
Because sodium bentonite expands when exposed to moisture, the membrane creates a self-sealing barrier around penetrations and small structural cracks.
Protection and Backfill
Once the waterproofing membrane was installed, protection layers were added to prevent damage during backfilling.
Backfill procedures were carefully managed to avoid disturbing the membrane and to maintain proper drainage conditions behind the foundation walls.
These considerations are especially important in hillside neighborhoods such as Pacific Palisades and Bel Air, where groundwater movement and soil pressure can be significant.
Critical Waterproofing Details
In most below-grade waterproofing projects, failures occur at transitions and penetrations rather than in the field membrane.
Special attention was therefore given to:
• foundation wall-to-slab transitions
• construction and cold joints
• pipe penetrations through the foundation walls
• tie-back locations and structural interfaces
• transitions between vertical and horizontal surfaces.
Addressing these details properly helps ensure continuity of the waterproofing system and long-term performance of the basement structure.
Results
The completed waterproofing system provides long-term protection against groundwater infiltration.
Key benefits include:
• durable below-grade waterproofing protection
• resistance to hydrostatic pressure from hillside groundwater
• self-sealing performance around penetrations and minor cracks
• reduced risk of moisture intrusion into basement living spaces.
The basement remains fully protected despite seasonal groundwater movement typical in hillside areas such as Pacific Palisades, Bel Air, and Beverly Hills.
Why Below-Grade Waterproofing Is Critical in Los Angeles Hillside Homes
Luxury homes in hillside areas throughout Los Angeles frequently include large basements constructed below grade.
Without a properly designed waterproofing system, these structures can experience:
• groundwater intrusion
• structural deterioration
• interior moisture damage
• mold and indoor air quality issues.
Professional waterproofing systems such as bentonite membranes help provide long-term protection for basement structures.
Surfacing and Waterproofing provides professional waterproofing services across Los Angeles, including:
Pacific Palisades
Bel Air
Beverly Hills
West Hollywood
Malibu
Our services include:
• basement waterproofing
• below-grade waterproofing systems
• foundation waterproofing
• retaining wall waterproofing
• swimming pool waterproofing
• hillside waterproofing systems.
Need Basement Waterproofing in Bel Air or Pacific Palisades?
If you are planning a hillside construction project or require professional basement waterproofing in Pacific Palisades, Bel Air, or Beverly Hills, our team can help design the right waterproofing solution.
Contact Surfacing and Waterproofing (323) 508-4033 to discuss your project and receive expert guidance on below-grade waterproofing systems.