The 2015 collapse of a balcony in Berkeley, California, which killed six people, exposed a systemic problem in the state's building stock: wood-framed balconies and elevated decks were deteriorating from concealed moisture damage, and no regulatory framework required their inspection. The California legislature responded with two landmark laws — Senate Bill 721 (2018) and Senate Bill 326 (2019) — that now impose mandatory inspection and maintenance obligations on owners of multifamily buildings with exterior elevated elements.

These laws have fundamentally changed the risk calculus for building owners across Southern California. Compliance is not optional, the deadlines are firm, and the findings from required inspections frequently reveal waterproofing failures that demand immediate remediation.

What SB 721 and SB 326 Require

SB 721: Apartments and Other Rental Properties

SB 721 applies to buildings with three or more multifamily dwelling units that are not governed by a homeowners association. It requires inspection of exterior elevated elements (EEEs) — including balconies, decks, walkways, and stairways — that are constructed of wood or wood-based materials and elevated more than six feet above grade. The initial inspection deadline was January 1, 2025, with subsequent inspections required every six years. Inspections must be performed by a licensed architect, licensed civil or structural engineer, or a certified building inspector or contractor with relevant experience.

SB 326: Condominiums and HOA-Governed Properties

SB 326 applies to condominium associations and other common interest developments. It requires inspection of the same types of exterior elevated elements but adds an important requirement: the inspector must provide a reasonable estimate of the remaining useful life of the waterproofing system and load-bearing components. The initial inspection deadline was January 1, 2025, with subsequent inspections every nine years. Inspections must be performed by a licensed architect or licensed civil or structural engineer — the qualified inspector pool is narrower than under SB 721.

Both laws require that if the inspection reveals conditions that pose an immediate threat to safety, the local enforcement agency must be notified and emergency repairs must commence.

Why Balcony Waterproofing Fails

The waterproofing systems protecting wood-framed balconies and decks in California have a well-documented history of failure. Several factors contribute to this pattern.

Original Waterproofing Deficiencies

Many balconies constructed during the building booms of the 1990s and 2000s were waterproofed with sheet-applied or liquid-applied membranes that were poorly detailed at critical transitions — deck-to-wall junctions, guardrail post penetrations, scupper and drain connections, and door thresholds. The California Building Code requires a minimum four-inch height differential between the exterior walking surface and the interior floor at door thresholds, but this dimension was routinely reduced or eliminated by builders seeking a flush aesthetic. Inadequate slope to drains compounds the problem by allowing standing water on membrane surfaces.

Guardrail Post Penetrations

Guardrail posts that penetrate the waterproofing membrane are the single most common point of water entry on balconies and decks. Each post creates a hole in the membrane that must be sealed with a compatible flashing system capable of accommodating the lateral loads and movement imposed on the railing. In practice, many guardrail posts are set directly through the membrane with only sealant as protection — a detail that degrades rapidly under load and weathering. For more, see Water Intrusion in LA Condos: What HOAs Need to Know.

Deferred Maintenance

Waterproofing membranes on balconies and decks are wearing surfaces subjected to foot traffic, furniture loads, UV exposure, and standing water. They require periodic maintenance including recoating of traffic coatings, replacement of sealant joints, and clearing of drains. Many building owners and HOAs defer this maintenance until visible damage appears — by which point moisture has typically been reaching the wood framing for years.

What Inspections Typically Reveal

Inspections conducted under SB 326 and SB 721 across Southern California have revealed widespread waterproofing distress. Common findings include:

  • Cracked, delaminated, or worn-through traffic coatings exposing the waterproofing membrane or substrate
  • Failed sealant joints at deck-to-wall transitions and guardrail bases
  • Inadequate or reversed slope causing ponding at the building wall rather than at drains
  • Missing or corroded sheet metal flashings at wall-to-deck junctions
  • Elevated moisture readings in plywood sheathing and framing members indicating active water intrusion
  • Fungal decay (dry rot) in joists, ledger boards, and rim joists that reduces structural capacity

When inspectors determine that the remaining useful life of waterproofing components is near or at zero, the building owner or HOA faces an obligation to fund and execute repairs promptly. For condominium associations, SB 326 findings feed directly into reserve study requirements, creating financial planning obligations as well.

Compliance and Risk Management

Building owners and HOAs who have not yet completed their initial inspections are now past the statutory deadline and face increasing enforcement risk. Beyond regulatory compliance, the practical risk is clear: concealed moisture damage in wood-framed balconies progresses silently and can lead to structural failure. Proper waterproofing assessment, timely repairs, and a funded maintenance program are not just legal obligations — they are essential life safety measures. Engaging a qualified building envelope professional to conduct inspections and develop remediation specifications ensures that the work addresses root causes rather than cosmetic symptoms.