Commercial Waterproofing · CSLB #1060736
Commercial Deck & Balcony Waterproofing — California
Membrane, coating, drainage, and sealant systems for multifamily, mixed-use, and HOA properties across the Bay Area — the single highest-leverage prevention investment on any deck or balcony.
- CSLB #1060736 Licensed California contractor
- 9+ yrs Building commercial balconies & decks
- SB 721 / 326 Trained — we build to pass
- Commercial Multifamily, HOA & mixed-use only
01 Why it matters
Every wood-rot job we touch traces back to a waterproofing failure
After years of repairing decks and balconies, the pattern is impossible to miss: every wood-rot job we touch traces back to a waterproofing failure no one inspected. A membrane that cracked at a seam, a sealant that wore through at a hardware penetration, flashing that was never tied into the wall — water found the wood, and the rot did the rest, invisibly, for years before anyone saw a soft board. The waterproofing envelope is the one system standing between weather and the structure.
That’s what makes it the single highest-leverage prevention investment on a deck or balcony. A dollar spent keeping the envelope intact prevents many dollars of structural repair down the line — and on California commercial property, it prevents the dry rot that turns an SB 721 or SB 326 inspection into a remediation scope. Deferring waterproofing doesn’t avoid the cost; it just trades a coating job today for a joist replacement tomorrow.
The catch is that waterproofing only works as an integrated system. A coating rolled over the surface does nothing if water is getting in behind it through bad flashing or a failed drain. The envelope — membrane, flashing, drainage, and walking surface — has to be built as one continuous system matched to California’s wet-dry climate cycles, not assembled from a stack of incompatible products.
Waterproofing is the highest-leverage dollar you can spend on a deck — because every structural repair we do started as a leak no one caught.
02 The D&B difference
One continuous envelope, proven systems, warranty in your file
D&B installs and renews waterproofing systems engineered for California climate cycles — integrating membrane, flashing, drainage, and walking surface as one continuous envelope, not a stack of incompatible products.
Integrated envelope, no unowned seams
Membrane, flashing, drainage, and the walking surface are installed as one continuous system by one crew — so there are no seams between products or trades for water to exploit. That integration is the difference between waterproofing that holds and a coating that delaminates at the edges.
Proven systems, no incompatible products
We install proven manufacturer systems — Carlisle, Sika, Westcoat, Mule-Hide, and coating systems like Westcoat, Pli-Dek, and Polycoat — and coordinate the walking surface to the membrane so nothing in the assembly fights anything else. The right system for the substrate, not a one-size coating.
Manufacturer-warranted, documented
We install to manufacturer specification so the system carries its warranty — and that warranty goes into your file. For a commercial property, a documented, warranted waterproofing system is both protection and the proof your compliance and asset file will want.
03 How a project runs
From leak diagnosis to a continuous waterproofing envelope
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01
Assessment & leak diagnosis
We inspect the deck or balcony, trace any active leak to its actual entry point — flashing, penetration, drain, or seam — and assess the substrate and existing waterproofing.
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02
System selection
We specify the right system for the substrate and California exposure — membrane, coating, or both — from proven manufacturers, and identify any drainage or structural issue the surface is hiding.
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03
Prep, flashing & drainage
Our crew preps the substrate, integrates flashing at the ledger, scupper, drain, and wall-tie, and corrects drainage — because a membrane over a bad detail or a clogged drain fails fast.
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04
Membrane, coating & surface
We install the membrane and coating system and coordinate the walking surface to it as one continuous envelope, with sealant renewal at control joints, edge details, and hardware penetrations.
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05
Warranty & handoff
We verify slope to drain and watertightness, and hand over the manufacturer-warranted system documentation for your compliance and asset file.
04 Scope
What’s included in a D&B waterproofing project
A complete deck and balcony waterproofing service — proven manufacturer systems, integrated into one continuous envelope, manufacturer-warranted and documented.
- Membrane systems — TPO, PVC, modified bitumen, liquid-applied polyurea
- Coating systems — Westcoat, Pli-Dek, Polycoat
- Flashing — ledger, scupper, drain, and wall-tie integration
- Drainage — scupper rebuild, internal drain replacement, slope correction
- Sealant renewal — control joints, edge details, hardware penetrations
- Walking surface coordinated with the membrane (no incompatible products)
- Manufacturer-warranted system installation — warranty in your file
Built as one continuous envelope: membrane · integrated flashing · corrected drainage · coordinated walking surface — engineered for California climate cycles, manufacturer-warranted
05 Investment
What commercial waterproofing typically costs
We quote every waterproofing project after an on-site assessment, because cost depends on the substrate, the system, and whether there’s hidden damage under the surface. These ranges reflect typical recent installed work.
What drives the number
- Substrate type and condition — plywood, concrete, or existing deck
- System selected — TPO, PVC, modified bitumen, polyurea, or coating
- Flashing integration required at ledger, scupper, drain, and wall-tie
- Drainage work — scupper rebuild, internal drain replacement, slope correction
- Square footage and number of balconies across the property
- Site access and phasing around occupied units
Ranges reflect typical recent commercial installed work. Because cost depends on the substrate and what’s beneath the existing surface, final pricing follows an on-site assessment — no obligation.
06 Project example
A recent balcony waterproofing project in Santa Rosa
A multifamily property in Santa Rosa had water staining the ceilings below a row of balconies after every storm. Two prior coating jobs had been rolled over the decks and both failed within a season — because nobody had found the actual leak. We traced it to a flashing detail at the door threshold where the membrane had never been tied into the wall, so the surface coating was irrelevant: water was getting in behind it. We rebuilt the flashing and threshold, corrected the drainage slope and a failed scupper, installed a manufacturer-proven liquid membrane integrated with the wall-tie, and coordinated a Westcoat walking surface to the membrane as one continuous envelope. We treated all nine balconies the same way and filed the manufacturer warranty for the owner’s records. The leaks haven’t returned through two rainy seasons.
Two contractors had already “waterproofed” these balconies and they kept leaking. D&B found where the water was actually getting in, installed a real warranted system, and put the warranty in our file. Night and day. Property Manager · Santa Rosa multifamily property
07 Client feedback
What property owners say
We’d recoated these balconies twice and they kept leaking. D&B diagnosed the actual entry point and rebuilt the whole envelope — membrane, flashing, drainage — as one system. The leaks stopped. That’s the difference between a coating and real waterproofing.
Our SB 326 inspection flagged failed waterproofing on a dozen balconies. They installed a proven manufacturer system matched to our concrete substrate and filed the warranty for our compliance records.
They were straight about what the substrate needed — a real warranted system, not a cheap coating that peels in a year. Highest-leverage money we’ve spent on the property.
08 FAQ
Deck & balcony waterproofing questions
How much does it cost to waterproof a deck or balcony?
Commercial waterproofing typically runs $25–$60 per square foot installed, depending on the substrate, the system selected, and whether there’s hidden flashing or structural damage to repair first. We give you a firm number after an on-site assessment — and we won’t quote a cheap coating that fails in a year.
My balcony keeps leaking even after it was “waterproofed.” Why?
Almost always because the actual leak was never found. Water usually enters at flashing, thresholds, drains, penetrations, or seams — not through the open field of the deck. A coating rolled over the surface does nothing if water is getting in behind it. We diagnose the real entry point first, then build the envelope as one integrated system.
What’s the difference between a coating and a waterproofing system?
A coating is the visible top layer. A waterproofing system is the membrane, flashing, drainage, and coordinated walking surface working together as one continuous envelope. A coating alone, over bad flashing or a failed drain, is a countdown to the next leak. We install integrated, manufacturer-warranted systems — not standalone coatings.
What systems and manufacturers do you install?
Proven systems matched to the substrate and California climate — Carlisle, Sika, Westcoat, and Mule-Hide membranes, and coating systems including Westcoat, Pli-Dek, and Polycoat. Membrane options range across TPO, PVC, modified bitumen, and liquid-applied polyurea. We specify what performs on your assembly rather than defaulting to one product.
Why does it matter that the system is “one continuous envelope”?
Because water exploits seams — between products, between trades, between the membrane and the wall. When membrane, flashing, drainage, and walking surface are coordinated as one system with no incompatible products, there’s no unowned interface for water to find. A stack of mismatched products fails at the joints between them.
Do you repair active leaks, or only install new waterproofing?
Both. A large share of our work is leak diagnosis and repair — finding where water is getting in and rebuilding the membrane, flashing, or drainage so it stops. We then waterproof the full assembly so it doesn’t reappear elsewhere.
Does the system come with a warranty?
Yes. We install to manufacturer specification so the system carries its manufacturer warranty — and we put that warranty in your file. On a commercial property, a documented, warranted waterproofing system is both your protection and the proof your compliance and asset records need.
09 Start here
Start with a waterproofing assessment
Seeing stains, leaks, or a coating that’s failing? It’s the highest-leverage problem to fix before it becomes a structural repair. Tell us what’s happening and we’ll assess the assembly, trace any active leak to its source, and specify a proven, manufacturer-warranted system for your substrate and California exposure. No obligation.
CSLB #1060736 · 9+ years · Insured & Bonded · Serving the Bay Area, Central Valley & Sacramento
