Below-grade waterproofing protects foundations, basements, and subgrade structures from moisture, groundwater pressure, and long-term deterioration. However, even the most advanced waterproofing system can fail if installed improperly. Across Los Angeles and neighboring regions like Malibu and Pacific Palisades, many projects suffer from recurring leaks or failures due to overlooked details.
Below-Grade Waterproofing Failure Points That Lead to Leaks
Some of the most common problem areas include:
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- Cold Joints: These are unavoidable in any multi-stage pour but must be treated with waterstops or bonding membranes. Ignoring cold joints creates a weak point where water finds a path.
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- Pipe Penetrations: Every pipe or conduit that goes through a wall or slab is a potential leak path. Boots, collars, or sealant systems must be installed to prevent intrusion.
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- Improper Termination Points: Where a membrane stops — such as at grade level or a wall transition — the detailing must be precise. Sloppy terminations result in peeling, delamination, or bypassing.
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- Underslab to Wall Overlap Failures: Membranes below the slab must tie into vertical walls. Failing to overlap or protect this junction leads to trapped water and interior leaks.
Best Practices to Prevent Waterproofing Failures in Foundations
To avoid costly repairs and callbacks, contractors should:
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- Hold Pre-Construction Coordination Meetings: Bring together the structural, waterproofing, and shoring teams before waterproofing begins.
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- Use Manufacturer-Compatible Systems: Mixing different brands for primer, membrane, and sealants often voids warranties and creates adhesion issues.
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- Include Details in Drawings: Generic notes won’t cut it. Each penetration, joint, and termination needs a detail. Review these during submittals.
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- Conduct Quality Control and Inspections: Before backfilling, membranes should be inspected for cuts, punctures, and adhesion issues.
Why These Mistakes Happen in Los Angeles Projects
Los Angeles is home to complex job sites, from hillside homes in Pacific Palisades to underground builds in Beverly Hills and commercial basements in West LA. Many projects are rushed to meet schedules, or subcontractors are not properly briefed. In high-pressure areas with slope runoff and rising water tables, poor detailing becomes a costly liability.
Final Thoughts
Waterproofing is a system — and systems are only as good as their weakest point. A premium membrane won’t perform if transitions are ignored or improperly sealed. By emphasizing detailing, pre-construction planning, and quality control, you significantly reduce the risk of failure.
If you’re planning a waterproofing project in Los Angeles, Malibu, or Pacific Palisades, IHC Construction Group (818) 540-5235 offers consultation and expert installation that ensures each layer, seam, and transition performs as designed.
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