Retaining Wall Waterproofing on a Hillside Property in Bel Air
This project involved waterproofing a large retaining wall system on a hillside property in Bel Air, Los Angeles. Hillside retaining walls in areas such as Bel Air, Pacific Palisades, Beverly Hills, and Hollywood Hills are constantly exposed to hydrostatic pressure, soil movement, and moisture intrusion.
This project was completed in Bel Air, where retaining wall waterproofing systems must perform under hillside soil pressure, groundwater exposure, and demanding below-grade conditions.
The objective was to protect the retaining wall structure from long-term water intrusion while ensuring durability under changing soil conditions.
For this reason, we installed a below-grade waterproofing system using Tremco TREMproof 250GC membrane technology.
This hillside project also included a flat roof waterproofing system. See our TPO roofing case study in Los Angeles using GAF systems for additional project details.
Project Overview
Location: Bel Air, Los Angeles
Project Type: Retaining wall waterproofing
Structure: Hillside retaining wall and below-grade foundation areas
Primary Waterproofing System: Tremco TREMproof 250GC
Application Type: Liquid-applied below-grade waterproofing membrane
The Challenge
Retaining walls built into hillside properties face continuous structural and environmental stress.
For example:
• hydrostatic pressure from groundwater
• soil expansion and contraction
• difficult waterproofing transitions
• penetrations and structural joints
• limited access after backfill
Because retaining walls remain exposed to moisture over long periods, the waterproofing system needed to provide flexibility, durability, and continuous protection. Therefore, proper detailing and membrane continuity were critical.
Waterproofing Installation Process
The installation began with preparation of the retaining wall substrate to ensure proper adhesion and long-term waterproofing performance.
The process included:
• cleaning and preparing the concrete wall surface
• repairing voids and surface irregularities
• application of Tremco TREMproof 250GC membrane
• reinforcement of transitions and penetrations
• waterproof detailing at joints and critical areas
In addition, special attention was given to wall transitions and penetrations, since these are common waterproofing failure points in below-grade construction.
Critical Retaining Wall Waterproofing Details
Several areas required precision waterproofing during installation.
These included:
• wall-to-footing transitions
• structural cold joints
• pipe penetrations
• changes in elevation and geometry
• termination and drainage areas
As a result, proper detailing helped create a continuous waterproofing barrier across the retaining wall assembly.
Results
The completed waterproofing system provides durable below-grade protection for the retaining wall structure.
Key outcomes included:
• improved resistance to groundwater intrusion
• flexible waterproofing protection for structural movement
• continuous waterproof membrane coverage
• reduced risk of long-term moisture damage
As a result, the retaining wall system is designed to perform reliably under hillside construction conditions in Los Angeles.
Why Retaining Wall Waterproofing Is Critical in Los Angeles
Retaining walls in hillside neighborhoods such as Bel Air, Beverly Hills, Pacific Palisades, and Hollywood Hills require carefully designed waterproofing systems.
Without proper waterproofing protection, retaining wall structures may experience:
• groundwater intrusion
• concrete deterioration
• moisture migration
• long-term structural damage
Therefore, below grade waterproofing plays a critical role in protecting hillside properties throughout Los Angeles.
Retaining Wall Waterproofing Services in Los Angeles
Surfacing and Waterproofing provides retaining wall and below-grade waterproofing services throughout:
Bel Air
Pacific Palisades
Beverly Hills
Hollywood Hills
Malibu
Services include:
• retaining wall waterproofing
• below-grade waterproofing
• basement waterproofing
• foundation waterproofing
• hillside waterproofing systems
Request a Waterproofing Consultation
If you are planning a retaining wall or below-grade construction project in Bel Air, Pacific Palisades, or Beverly Hills, we can design a waterproofing system tailored to your project.
Contact Surfacing and Waterproofing (323) 508-4033 for guidance on retaining wall waterproofing systems or send plans and specifications.