How We Waterproof in Los Angeles
Waterproofing is all about the structural system underneath. In Los Angeles, the sun bakes your deck all summer, and the winter rains find every microscopic gap in your flashing. If the engineering isn’t right, the waterproofing won’t be either. Here’s how we do it at Angel City Development.
Forensic Site Evaluation
We don’t guess. We start by looking for the why behind the leak. Most crews just want to patch the visible damage, but we look deeper.
Identifying the Root Cause
We check the structural integrity of the joists and look for dry rot hidden behind the stucco. We verify if your subfloor is salvageable or if the water has already compromised the bones of the building.
Slope and Drainage Assessment
Water stays where it’s invited. We calculate the pitch of your deck to see if it’s actually directing water toward the drains. If your deck is ponding, no amount of sealant will save it long-term.
Structural Correction & Rebuild
Before a single drop of membrane is applied, the surface has to be right. We fix the structural failures that caused the leak in the first place.
Wood and Metal Replacement
If we find rotted plywood or rusted metal during the teardown, we cut it out. We don’t bridge over rot. We replace it with high-grade materials that meet or exceed current LA building codes.
Correcting the Pitch
If the deck is flat or sloped toward the building, we re-slope it. We ensure the water has a clear, gravity-fed path to the scuppers or drains so it never has a chance to sit and soak into the system.
High-Stakes Flashing & Transitions
95% of waterproofing failures happen at the edges – where the deck meets the wall, the railing posts, or the door thresholds.
Custom Metal Flashing
We use custom-fit metal flashing designed to handle the thermal expansion of the LA sun. Every corner and transition is reinforced to ensure the seal doesn’t crack when the building settles.
Door and Threshold Integration
The door leading to your balcony is the most vulnerable point on the entire deck. We focus on the pan flashing under the door frame to make sure water can’t crawl back into your living room during a wind-driven rainstorm.
System-Specific Armor
Every property has different needs. We don’t push a one-size-fits-all product; we apply the system that fits your specific traffic and aesthetic
Under-Tile Systems
These are specialized, multi-layer membranes that live beneath stone or tile. They have to be bulletproof because once that expensive stone goes down, you don’t want to see that membrane again for thirty years.
Finish-Coated Surfaces
For high-traffic walkways and balconies, we use UV-resistant coatings that can breathe. These are built to take a beating from foot traffic and the sun without cracking, peeling, or delaminating.
Testing & Compliance Sign-Off
We don’t just pack up and leave. We prove the system works before we consider the job done.
Flood Testing
Where necessary, we plug the drains and flood the deck. If it can hold two inches of standing water for 24 hours without a drop leaking through, it’s ready for the final finish.
SB 721 & 326 Documentation
If your project is part of a state-mandated inspection, we ensure every repair meets the specific load-bearing and safety requirements. You get a finished product that isn’t just dry but documented and fully compliant with California law.
Stop Managing the Leak.
If you’re tired of maintenance that doesn’t actually stop the water, let’s get a real plan in place. Reach out to us and we’ll give you a straight answer on what it takes to protect your building for the long haul.