Deck & Balcony Rot Repair · CSLB #1060736
Commercial Deck & Balcony Rot Repair in California
We repair rot in decks, balconies, walkways, and stairs across the Bay Area, Central Valley, and Sacramento. Deck rot and balcony rot are the same fungus in different structures, and cutting out decayed timber is the visible half of this work. The half that decides whether you do it again is water — because rot doesn’t stop when you replace the wood, it stops when the wood stays dry.
- CSLB #1060736 Licensed California contractor
- 9+ yrs Repairing rot in decks & balconies
- Water first Source corrected before the timber goes back
- Commercial & HOA Apartments, condominiums, HOAs & hotels
Where to start
Rot Repair by Structure
A deck loses section with posts still sharing the load; a cantilevered balcony has nothing behind the wall line. Pick the page for your structure.
CSLB #1060736SB 721 / SB 326 documentedCommercial, multifamily & HOA
Free quote · no obligation
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01 Why it matters
You stop rot with water, not with chemistry
Wood-destroying fungi need moisture in the timber itself — above roughly twenty percent moisture content they grow, and below it they don’t. That single fact is the whole of rot control, and it explains why most attempts to stop it fail. Treatments get applied to wood that is still wet and still being wetted, and the fungus carries on because the condition it depends on hasn’t changed. Borate and similar products have a real role as a preventive in dry timber; they are not a cure for a member that water is still reaching.
Which means stopping rot is a plumbing problem rather than a chemistry problem. Find where the water is arriving — an unflashed ledger, a threshold draining toward the building, a coating that stopped working, a post base sitting in a puddle — and remove it. Let the timber dry below the threshold. Give it a way to stay there: drainage that leaves, joist tops that shed, ventilation where the assembly allows it. Do that and the fungus stops, whether or not anything was ever brushed onto the wood.
Two honest qualifications on that. Drying arrests growth but does not restore what has already been lost — timber that has given up section stays weak whether it’s wet or dry, which is why arresting rot and repairing it are separate jobs. And the same logic explains why an identical detail produces identical results across a property: the buildings in these photographs have decay on the upper balconies and the ground-floor decks alike, because the same water was arriving at both for the same reason.
Treating wet wood and leaving the leak is paying for chemistry to lose an argument with a plumbing problem.
02 The D&B difference
What proper rot repair involves
The water is found before the wood is replaced
Every repair starts with where the moisture is arriving. New timber into unchanged conditions restarts the same clock, which is the single most common reason this work gets paid for twice.
Cut back past the visible edge
Decay extends into timber that still looks and sounds sound. We probe out to material that resists a probe and cut past it rather than stopping where the damage stops being obvious.
Structural repair, not filler
Consolidants and epoxy have legitimate uses on trim. They do not restore the capacity of a joist, a beam, or a post, and we won’t use them where structure carries people at height.
03 · Service Areas
Where We Work in California
Every city links to a dedicated local page — crews, recent projects and compliance details for that area.
Sacramento Metro
11 cities
East Bay
18 cities
Don’t see your city? We likely still cover it — call (916) 848-2728.
04 How a project runs
How we repair deck rot and balcony rot
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01
Assessment
Probe testing across joists, beams, ledgers, and post bases, with moisture readings, and openings where the critical section is enclosed.
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02
Source identification
Where water is arriving at each affected point, because that determines what has to change beyond the timber.
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03
Scope & estimate
Written extent with a stated allowance for what opening up may add, and a clear recommendation where rebuilding is the better value.
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04
Support
Element taken out of service and shored where the loss of section requires it.
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05
Removal & replacement
Decay cut back to sound material; joists, beams, rims, and posts replaced or sistered with rated connectors.
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06
Cause correction
Ledgers flashed, thresholds redetailed, joist tops taped, drainage corrected, waterproofing reinstated.
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07
Handover
Photographs of what was found and what went back, plus SB 721 / SB 326 compliance file material.
05 Scope
What we repair
Rot repair across decks, balconies, walkways, and stairs, from one CSLB-licensed crew.
- Probe testing and moisture readings across the framing
- Identification of the water source at each affected point
- Openings where the critical section is enclosed behind stucco or soffit
- Temporary shoring and removal from service where section loss requires it
- Deck rot repair — joists, beams, rims, ledgers, posts, and stair stringers; dry rot deck repair included
- Balcony rot repair including cantilever joists at the wall line
- Dry rot on deck and balcony framing, and wet rot, cut back to sound material
- Members replaced or sistered with rated connectors
- Building framing repaired where water has reached it
- Ledger connections rebuilt and flashed per CBC 1604.8.1
- Joist tape and flashing over joist tops before surfaces go back
- Threshold and drainage detailing corrected so water leaves
- Waterproofing reinstated as a continuous system
- Preventive treatment where timber is dry and staying dry
- Honest assessment when the extent makes rebuilding the better value
- Documentation for the SB 721 / SB 326 compliance file
Built to current code: CBC 1604.8.1 ledger connections · ASCE 7 load criteria · rated connectors and structural fasteners
06 Investment
What rot repair costs
The cost to repair wood rot on a deck or balcony is quoted after probing, and the estimate has to account for what probing can’t fully reach.
What drives the number
- How many members are affected, and whether they’re joists, beams, ledgers, or posts
- Where the damage sits — a ledger or a cantilever connection costs more than a joist mid-span because of what has to be supported while it’s out
- Whether members can be sistered or must be fully replaced
- Whether the building’s own framing has been reached
- The cause corrections needed at each location
- Temporary shoring and time out of service
- How many elements on the property share the same detail and condition
Why the number can move, and how we handle it: decay reaches beyond what a probe finds, and the type that travels reaches further again. We state an allowance in the estimate rather than presenting it later as a change order — and where the assessment suggests the damage is likely extensive, we say so before you commit.
What the cause correction is worth: it’s usually a small fraction of the repair and it’s the entire difference between doing this once and doing it again. A quote that replaces timber without a line for flashing, thresholds, or drainage is quoting half a job at a competitive price.
Final pricing follows an on-site assessment. Request a free estimate — no obligation.
In the field
Rot repair detail
What the surfaces were covering, across decks and balconies alike.
07 Project example
A recent rot repair
A property had rot reported on two balconies and had been treating it — a contractor had been out twice with a preservative and the timber had carried on deteriorating. The reason was simple once anyone looked: the water hadn’t gone anywhere. Thresholds drained toward the building rather than away, and the ledger detail behind them had never been flashed. Treatment applied to timber that was being wetted continuously was never going to do anything. D&B probed the elevation, found the same detail and the same condition at different stages on every element, cut back to sound material, rebuilt and flashed the connections, redetailed the thresholds so water leaves, and reinstated the waterproofing. The preservative went on afterwards, where it belongs — on dry timber, as prevention.
We’d paid twice for treatment. Nobody had mentioned that the wood was still getting wet. Regional Property Manager · California apartment community
08 Case studies
Recent Projects, Documented
Real commercial properties — what the building needed, what we did, and what it delivered.
WaterproofingElevated Walkway & Balcony Waterproofing — 40-Unit Apartment Community, Rio LindaDry rot had opened holes straight through the walkway decks. We shored the spans, rebuilt the framing underneath,…View case study 
Deck RepairElevated Deck Reconstruction & Waterproofing — 24 Balconies, SacramentoOpen board decks sitting directly over enclosed garages. Every gap between the boards was a route for water…View case study 
WaterproofingBalcony & Exterior Stair Waterproofing — 32-Unit Multifamily Community, SacramentoThe rot wasn't out at the edge — it was where the deck met the wall. We stripped…View case study 09 Client feedback
What property managers say
We’d paid twice for treatment. Nobody had mentioned that the wood was still getting wet.
They explained that drying stops the fungus but doesn’t bring the strength back. That’s why we replaced rather than dried and hoped.
The same detail was wrong on every balcony on that elevation. Once they’d found it on one, they knew where to look on the rest.
10 FAQ
Rot repair questions
How do you stop wood rot on deck framing?
By removing the water, not by treating the wood. Wood-destroying fungi need moisture in the timber above roughly twenty percent to grow, and below that they stop. So stopping wood rot on deck and balcony framing means finding where water is arriving — an unflashed ledger, a threshold draining the wrong way, a failed coating, a post base in standing water — removing it, and giving the timber a way to stay dry. Do that and the fungus stops regardless of what was applied to the surface.
Does treating the wood work?
As prevention on dry timber, yes. As a cure for wood that water is still reaching, no. Preservatives can’t change the condition the fungus depends on, so applying them to a member that stays wet buys nothing but the appearance of action. We use them where they belong — after the source is corrected and the timber is dry.
If the deck dries out, is the rot fixed?
The rot stops. The damage doesn’t reverse. Drying arrests the fungus because it removes what it needs, but timber that has lost section has lost strength permanently — it stays weak whether wet or dry. So arresting rot and repairing it are two separate jobs, and one doesn’t substitute for the other.
What’s the difference between dry rot deck damage and wet rot?
Both need moisture; the names are misleading. Wet rot stays where the water is, so it’s contained and the repair boundary is straightforward once the source is found. The type usually called dry rot can carry water along its own strands and attack timber some distance from the original leak, which is why the affected wood can look dry and why the search has to be wider. The practical difference is how far you cut.
What’s the cost to repair wood rot on deck framing?
It depends on how many members are affected and where. A joist mid-span is straightforward; a ledger, a cantilever connection, or a post is more, because the structure has to be supported while the member is out. On top of the timber comes correcting the cause, which is usually a small fraction of the repair and the whole difference between doing this once and doing it twice.
Can you repair deck joist rot without replacing the whole joist?
Often, by sistering — a new member fixed alongside the sound portion, spanning past the damage to bearings at both ends. It works where the decay is localised and the bearings are sound. It doesn’t work where the loss is at the bearing itself or where the member is compromised along its length, and in that case a sister just transfers the problem.
Is rot on a balcony different from rot on a deck?
Structurally, yes, and it’s worth knowing which you have. A deck losing section at the ledger still has posts and footings sharing the load. A cantilevered balcony carries everything at the line where its joists enter the wall, and there’s nothing behind it — the same loss of section is a repair item on one and a structural condition on the other. We have separate pages covering each in more detail.
Are you rot repair contractors in California?
We’re a CSLB-licensed contractor (#1060736) repairing rot across the Bay Area, Central Valley, and Sacramento, exclusively on commercial, multifamily, and HOA property. Probing, shoring, structural repair, flashing, and the drainage corrections come from one crew — because separating them is exactly why rot repairs come back.
11 Start here
Find the water, then price the repair — free assessment
Tell us what you’re seeing: a soft board, a spongy step, a dark post base, a stain on a ceiling below. We’ll probe the framing, find where the water is arriving, and give you a written scope with the timber and the cause both priced.
CSLB #1060736 · 9+ years · Insured & Bonded · Commercial, multifamily & HOA properties across the Bay Area, Central Valley & Sacramento