We check for moisture behind the surround before demo begins — not after the walls are open. Waterproofing membrane, permitted plumbing, and LADBS-inspected wet areas under CSLB License #1074505.
CSLB License #1074505
Itamar Ben Asulin on every project
Valley · Westside · South Bay
Bathroom remodeling in Los Angeles means permits, waterproofing, and wet area compliance — not just new tile. Every project IBA takes on starts with a substrate assessment before demolition begins.
IBA Builders handles full-scope bathroom renovation under a single CSLB-licensed contract. That includes wet area waterproofing — the material layer behind tile in showers and tub surrounds that California code requires before any tile is set — permitted plumbing modifications, tile installation, fixture replacement, and ventilation upgrades. Our custom bathroom design and remodeling service covers every element from substrate to fixture finish.
This is a permitted renovation. It produces a bathroom with inspected waterproofing, code-compliant plumbing, and a final sign-off from LADBS through the LADBS final inspection and sign-off process. Los Angeles homes built in the 1950s through 1980s frequently have deteriorated backer material behind original tile work — identifying that before demo keeps the project on scope.
The six workstreams managed on every bathroom remodel — substrate through final inspection — under one CSLB-licensed contract.
Applied to all wet areas — shower walls, tub surrounds, shower floors — before tile is set. Meets ASTM C627 tile assembly standards required by LADBS.
Existing backer assessed before demo. Deteriorated greenboard, rotted framing, or compromised cement board is replaced — not tiled over.
Plumbing supply and drain connections confirmed against the specified fixtures before walls close. Rough-in dimensions match the actual fixtures on order, not generic standards.
Layout planned against the room’s actual dimensions. Large-format and pattern layouts mapped to avoid narrow cut pieces at visible edges.
Mechanical exhaust confirmed or upgraded to meet California code before work begins — not flagged as a correction at final inspection.
All applicable building and plumbing permits pulled under CSLB #1074505 and inspected through final sign-off. We file, monitor, and respond to correction notices.
Site visit and substrate assessment. Moisture readings at the base of the shower surround and floor pan. Backer material behind existing tile inspected for water intrusion before demo is scheduled.
Building permit, plumbing permit, or both filed with LADBS based on what moves. Permit applications submitted before demolition begins — not after walls are already open.
Existing tile and substrate removed. Compromised backer replaced where needed. Waterproofing membrane applied to all wet area surfaces, inspected by LADBS before tile is set.
LADBS final inspection covers waterproofing assembly, plumbing work, and ventilation compliance. We schedule and attend the inspection. Documentation confirming finaled permit delivered at close-out.
We focus on neighborhoods where aging plumbing infrastructure is most common. The San Fernando Valley (Van Nuys, North Hollywood, Reseda, Woodland Hills, Tarzana, Sherman Oaks, Studio City, Encino, Chatsworth, Canoga Park) and Central/East LA (Mid-City, Silver Lake, Echo Park, Los Feliz, Highland Park, Glassell Park) hold a significant share of LA’s 1950s–1980s residential housing stock — single-vent bathrooms, cast iron drain lines, single-wall fiberglass surrounds over greenboard, and no waterproofing membrane. We also work the Westside and South Bay (Culver City, West Hollywood, West LA, Inglewood, Hawthorne, Torrance). When a bathroom project reveals broader infrastructure issues, homeowners sometimes pair it with a full house remodel or extend into kitchen remodeling during the same engagement.
Most of the moisture damage we find in older LA bathrooms was never visible from the surface. The homeowner in Van Nuys had a 1972 home with 4-by-4 ceramic tile in the original shower — the kind found in nearly every San Fernando Valley home from that decade. Grout had been resealed a few times. From the surface, the shower looked fine.
“Our substrate assessment showed elevated moisture in the greenboard behind the lower two courses of tile. This shower had no waterproofing membrane — the greenboard near the floor had been wet long enough that the paper facing was separating from the gypsum core. Because we found it before demo, substrate replacement and membrane installation went into the project plan before any wall was opened. The homeowner approved the revised scope. No mid-project surprises.”
— ITAMAR ASSULIN, OWNER, IBA BUILDERS
The permit trigger on a bathroom remodel isn’t the size of the project — it’s what moves. Replacing a toilet in the same rough-in requires no plumbing permit. Moving that toilet three feet relocates a drain line, and that triggers a plumbing permit through LADBS. As a CSLB-licensed contractor serving Los Angeles under License #1074505, we identify which permit types apply before any work begins — you can verify our standing through the California Contractors State License Board portal. California code also requires mechanical exhaust ventilation in bathrooms lacking an operable window — see the bathroom ventilation and energy efficiency guidance for context. We check this at design, not at the end.
Generally no — if nothing moves and the rough-in stays where it is, you typically don’t need a plumbing permit. But the moment a drain line, supply line, or vent stack relocates — even by inches — a plumbing permit is required. We assess your specific scope at the first site visit and tell you exactly which permits apply before any work starts.
Greenboard is moisture-resistant drywall — the standard backer material in bathrooms through the 1990s. It’s moisture-resistant, not waterproof. When the waterproofing membrane is absent or has failed (common in homes built in the 1950s through 1980s), greenboard absorbs moisture over time. The damage isn’t visible from the surface — the paper facing eventually separates from the gypsum core. Our substrate assessment catches it before demo, not after walls are open.
Most permitted bathroom remodels run six to ten weeks from permit issuance to final inspection. The variables are scope (a primary bath with relocated plumbing takes longer than a secondary bath with fixtures in the same place), substrate condition (significant deterioration adds days or a week), and LADBS plan check speed. Cure times on membrane and grout are part of the schedule — we don’t rush them.
If your bathroom has no operable window of sufficient size, California code requires mechanical exhaust ventilation. If you have a window, ventilation may be met naturally. Either way, the inspector checks compliance at the final inspection — we confirm and document the configuration during the design phase so there’s no correction at the end.
ASTM C627 is the tile assembly standard LADBS references for waterproofing in shower and tub installations. The membrane has to be installed to the manufacturer’s specification, with proper overlaps at floor-to-wall transitions, before tile goes on top. We apply it on every wet area — not just where leaks were visible — and the assembly is inspected by LADBS before tile is set.
A bathroom remodel starts with understanding what’s behind the existing tile and which permits your scope requires. Tell us what you’re planning — we’ll confirm the permit requirements and assess the substrate condition before any demolition begins. If you’re still evaluating contractors, review what to verify before hiring a remodeling contractor.