Case Study · SB 326 · CSLB #1060736
Balcony Waterproofing Before Framing Damage — 38-Unit HOA, Cupertino
38 covered balconies stripped and recoated after SB 326 findings — the old coating had failed, but moisture readings showed the plywood under it was still dry, so no framing had to be replaced.
WaterproofingProject facts
- Location
- Cupertino, CA
- Service
- Waterproofing
- Property
- Three-story HOA condominium community with covered balconies
- Units
- 38
- Client
- HOA board
- Scope
- 38 balconies stripped and recoated · turned-up base at walls and door sills · railing post bases sealed · moisture readings on every balcony
- Timeline
- 5 weeks · residents in place
- Completed
- Q3 2026
- Budget range
- $70k–$95k
01 The situation
The challenge
The SB 326 report listed the balcony coating as failed. Across the decks it had worn through to the base layer in patches and cracked along the plywood seams, and at the edges it had pulled away completely — along the base of the walls, at the sliding-door sills and around the plates of the railing posts. Those edges are where a coating moves the most and where water reaches the deck first.
The board expected the worst: a failed coating usually means wet plywood, and wet plywood means opening the balconies and replacing framing. Before anyone priced that, the board needed to know whether the water had actually got through. The balconies are covered and set into the building, they are each unit’s only outdoor space, and residents were living there throughout, so the work had to be planned around short closures and cure times.
02 Execution
What we did
We confirmed the condition of the wood first, then replaced the coating:
Took moisture readings across every balcony and opened the coating at the worst spots to confirm the plywood underneath was dry and sound
Ground off the failed coating down to a clean substrate, masked and protected the sliding doors, and repaired the cracks along the plywood seams
Built a continuous turned-up base where the deck meets the walls and the door sills, and sealed around every railing post plate — the places where the old coating had pulled away first
Applied a new fluid-applied coating system with a reinforced base and a textured slip-resistant topcoat, closing each balcony only for its cure time
03 Outcome
The result
Every balcony now has one continuous coating that turns up at the walls and door sills and seals around the railing posts, so the edges that failed first are now the most protected part of the deck. Because the problem was caught while the plywood was still dry, the project stayed a coating job — no balcony had to be opened to the framing. The waterproofing findings were closed with documentation for the next SB 326 cycle, and the moisture readings were recorded as a baseline for the next inspection.
Results at a glance
- 38 balconies stripped and recoated
- Plywood confirmed dry and sound before coating — no framing replaced
- Turned-up base at walls and door sills, sealed railing post bases
- Each balcony closed only for its cure time
What the client received
- Closeout documentation for the SB 326 waterproofing findings
- Moisture readings for every balcony, recorded as a baseline
- Coating manufacturer's warranty plus our workmanship warranty
- Topcoat maintenance schedule for the association's reserve plan
Transformation
Before & After
Balcony deck coating
Wall corner and post base
“We were told the coating had failed and expected to rebuild balconies. The readings showed the wood was still dry, so we paid for a recoat, not new framing.”
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