LA’s older homes hide something most of SoCal lacks: real basements. Cellars, below-grade rooms, subterranean garages. After 80 years, most of them leak. We make them dry enough to actually use.
The LA basement problem nobody built for
Ask around, and people will say LA homes have no basements. Tell that to anyone who owns a pre-war house here. Craftsman, Spanish Revival, and Victorian homes went up from the 1900s through the 1940s. Builders dug cellars for furnaces, storage, and cool air.
Here is the catch. Those basements came before modern waterproofing existed. Unsealed concrete or brick walls. No exterior membrane. No perimeter drain. Just wall against soil.
For dry years, that was fine. Then a wet winter arrives. The soil saturates. Pressure builds against the walls. Water finds every unsealed path in.
The result is the classic LA basement. Musty. Damp. White mineral bloom on the walls. Maybe a puddle every February. Usable only as reluctant storage. And that is a real waste — because in this city, dry below-grade space is worth a small fortune.
Why LA basements are suddenly worth fixing
Two things changed. Both of them make the water the first problem to solve, not the last.
A dry basement is livable square footage. In LA, square footage is the whole game. Home office. Gym. Studio. Storage that does not ruin what is stored.
LA homeowners are converting every space that can hold a rental unit. Basements and subterranean rooms are on that list. But no conversion survives a wet wall. Waterproofing is not a step in that project. It is the first step — before a single stud goes in.
Thinking about finishing or converting below-grade space? Then the order matters more than the budget. Handle the water first. Everything built after it stays built.
Waterproofing services available in Los Angeles
Each service starts from where the water actually enters, not from where the stain appears.
No excavation
Perimeter drainage, wall membranes, and sump systems, installed from inside. No excavation. No ruined landscaping.
For a tight LA lot with no side-yard access, this is often the only practical route. See the method on our interior and exterior waterproofing page.
Their own physics
Below-grade garages, cellars, and rooms cut into slopes have their own physics. More soil pressure. Less airflow.
A room that is mostly or fully underground behaves differently from a standard basement. The drainage and sealing plan has to match that, not a template.
Through the wall
Is water coming through the foundation walls themselves? Then the wall system needs sealing.
It is the most common question we get about an old cellar wall, and the answer changes the scope. Our foundation waterproofing page explains.
Water already inside
Active leaks, seepage at the wall-floor joint, standing water. The entry path gets found before anything gets sealed over it.
Sealing first and looking later is how the same leak comes back in a different spot. The steps are on our wet basement repair page.
Under the floor
Plenty of LA homes have crawl spaces too. A wet one damages the floor structure above it for years before anyone notices.
Some homes have basement and crawl space zones under a single footprint. See what turns up on our crawl space waterproofing page.
Storm protection
Does your basement sit below the water line during storms? A pump system turns a wet week into a non-event.
Sizing and backup options are on our sump pump installation page.
Before it reaches the wall
Sometimes the wall is not the problem. The yard is. The water just arrives at the wall.
Cutting water off before it reaches the structure costs less than managing it afterwards: French drain installation.
Planning to finish or convert your basement?
The waterproofing scope changes when living space goes on top of it. Knowing early saves you from paying for the wrong version.
Serving Los Angeles from the San Gabriel Valley
We serve homeowners across Los Angeles and nearby areas, alongside our core Pasadena service area. Service depends on the address, site conditions, access, and the requested work. Closer to the San Gabriel Valley? Our home turf is mapped on the Pasadena service area page.
Los Angeles FAQs
Most of them start the same way: does my LA home even have a basement worth saving?
Ask about your property →The older ones often do. Homes built from the 1900s to the 1940s were often built with cellars or partial basements. Many pre-war and hillside properties include subterranean rooms or below-grade garages. Does your home predate World War II? Then there is a real chance usable space sits under it.
Because LA’s rain arrives all at once. Dry months keep the soil low on moisture. Then storms saturate it fast. Pressure builds against below-grade walls, and water finds every unsealed path. A basement that is dry ten months a year is still a wet basement.
Very likely — but waterproof it first. Before framing, insulation, or drywall. Sealing and drainage planned around the conversion is the difference between an asset and mold behind new walls. Your ADU professional handles permits. We make the space dry enough to build in.
It depends on the entry path and the wall condition. Drainage, sealing, a pump, or a mix — each is a different scope. You get a written, itemized price after inspection. Not a guess over the phone.
Waterproofing for spaces mostly or fully below ground. Subterranean garages, cellars, and rooms cut into slopes. These carry more soil pressure and less airflow than a standard basement. The drainage and sealing plan matches that.
Both. Many LA homes have crawl spaces. Some have basement and crawl space zones under one footprint. The inspection covers whatever sits under your home.
Interior perimeter systems usually run a few days. Small sealing jobs are shorter. Full drainage-plus-pump systems take longer. Your written scope includes the timeline before you commit.
Call +1 (626) 898-6249 or use the contact form. Send your address and where the moisture shows up. We confirm coverage, inspect, and put everything in writing.
Get started
In Los Angeles, square footage is everything. Yours should not be growing mold in the dark.