Substrate and transition review
Confirm the receiving surface, penetrations, walls, edges, drains and terminations before concealed work begins.
Hidden waterproofing that cannot be an afterthought
Under-Tile & Below-Grade Waterproofing in Los Angeles & Orange County
Specialized membrane installations beneath tile and at below-grade structures, foundations, retaining walls and planters throughout Los Angeles and Orange County.
Experienced waterproofing since 1985
Under-tile, foundation & planter waterproofing
Leaks beneath tiled balconies, moisture at foundation or retaining walls and leaking built-in planters often involve a membrane hidden behind finishes or soil. We determine what must be opened to reach the substrate, then review drains, wall-to-floor joints, penetrations and membrane terminations before proposing repairs. Coating tile or grout alone does not replace a failed concealed waterproofing membrane.
For an under-tile deck, the scope may include removal of the affected finish, substrate preparation, a compatible membrane connected at thresholds, walls and drains, protection and testing when specified before tile is replaced. For below-grade walls or planters, the scope must also account for access, drainage, membrane protection and the sequence of excavation, soil removal and backfill. The proposal identifies which removal, structural repairs, tile, landscaping and other trade work are included or separately coordinated.
How the work is approached
A complete scope—not just a surface coating
Membrane installation
Install the specified compatible system with reinforced details at vulnerable changes in plane and penetrations.
Trade coordination
Coordinate protection, flood testing when specified, drainage components and the sequence for tile, backfill or finishes.
Where the waterproofing is needed
A scope matched to the concealed area
Below-grade walls & foundations
We evaluate waterproofing at retaining and foundation walls, basements, subterranean garages and elevator pits. The accessible side of the structure, wall material, leak path and existing conditions determine the repair approach. Exterior membrane work must coordinate with excavation, protection and backfill. When the exterior cannot be accessed, a different investigation and repair specification may be needed.
Understand concealed waterproofing systemsBuilt-in planter waterproofing
Planter repairs begin with access to the lining, substrate, wall junctions and outlets. We review membrane continuity, protection and the sequence for removing and reinstating soil or finishes. The proposal should identify who handles planting and irrigation work so the waterproofing is protected when the planter returns to use.
Planter waterproofing and care guideWaterproofing beneath tile & stone
CIM 1000 is our first system to evaluate for suitable under-tile conditions. The complete assembly includes prepared substrate, compatible wall and threshold details, membrane protection and the specified finish installation. Any required testing is planned before the work is concealed by tile or other finishes.
Compare materials by applicationSpecified for the existing assembly
Waterproofing systems we install
We do not force one product onto every deck. The appropriate system depends on the substrate, existing assembly, exposure, expected traffic and project requirements.
CIM 1000 Waterproofing Membrane
A two-component, liquid-applied urethane membrane considered for compatible horizontal under-tile and stone assemblies, between-slab conditions, planters and other concealed waterproofing applications. CIM 1000 TG may be used at compatible vertical details, joints and transitions when specified.
Waterproofing Underlayments
ALX and MACoat underlayment options considered for compatible assemblies designed to receive tile, stone or another approved wearing surface.
TREMproof 250GC
A single-component, fluid-applied polyurethane membrane for compatible below-grade concrete walls, split slabs and planters. The specified assembly includes transition details, membrane protection and coordinated backfill or covering work.
BG2000
A below-grade waterproofing system considered for compatible concrete and masonry conditions as part of a complete concealed-wall and protection assembly.
Final product selection and specifications are confirmed after the property and existing deck assembly are evaluated.
Common applications
Projects we can evaluate
The final recommendation depends on site conditions, access, the existing assembly and what is uncovered during approved preparation or demolition.
- Tile balconies and decks
- Foundations
- Retaining walls
- Below-grade walls
- Planters
- Buried and concealed surfaces
Questions customers ask before starting
Under-Tile & Below-Grade Waterproofing FAQs
These answers explain the decisions that usually affect scope, scheduling and system selection. The final recommendation is based on the conditions at your property.
Ask about your projectDoes tile itself waterproof a balcony or deck?+
No. Tile, grout and setting materials are finish components; the approved waterproofing membrane below them protects the assembly. The membrane must connect correctly at walls, edges, penetrations and other transitions before it is concealed.
Can an under-tile leak be repaired without removing the tile?+
A localized surface detail may occasionally allow a focused repair, but a failed concealed membrane often cannot be reached or reliably evaluated without removing tile and setting materials in the affected area. The leak pattern and existing assembly should be investigated first.
What is included in below-grade waterproofing planning?+
The review considers the substrate, wall condition, changes in plane, penetrations, terminations, drainage path, protection and the sequence for backfill or adjoining construction. A membrane alone is only one part of that concealed assembly.
When should flood testing and trade coordination occur?+
When specified and appropriate for the assembly, testing occurs after the membrane and critical details are complete but before tile, protection board, backfill or other finishes hide the work. The sequence should be agreed with the tile setter, general contractor and related trades in advance.
Start with a site evaluation