Compare repair decisions
Water Damage Below a Kitchen Sink: Cabinet Base, Floor or Both?
Separate the active plumbing leak, the cabinet base and the floor beneath a kitchen sink into three repair scopes before comparing proposals or approving work.
A damp or swollen area below a kitchen sink can raise three different questions at once: whether the water is still active, what has happened to the cabinet itself, and whether the floor nearby is affected. These are not the same question, and a single company walking through your kitchen does not automatically mean a single scope of work. This guide separates the plumbing, the cabinet, and the floor so you can read a repair proposal with the right questions in hand. It does not identify the cause of any particular case; a local review of the actual cabinet, plumbing and flooring settles that.
What you can see, and what the cabinet still hides
From outside the cabinet you can safely note a swollen or delaminated toe-kick, a stained or swollen cabinet floor, a door or drawer that no longer closes the way it used to, or a faint odor when the cabinet is opened for normal use. Write these down, and photograph the cabinet interior and the floor in front of it as it sits. That is the limit of a safe look: do not pry up the cabinet floor, pull the drain trap apart, or lift flooring to see farther in.
A visual check cannot tell you what is happening behind the cabinet's back panel, under its base, or beneath the floor covering itself. That is established once the area is opened and documented using recognized wood-condition assessment methods such as visual inspection, ultrasound or probing, not a guess from the outside. How far any affected material extends past what you can see is exactly the kind of detail that belongs in a written scope rather than an assumption.
Three different providers, three different jobs
An active supply line, drain trap, disposal connection, or dishwasher line is plumbing work; EPA's mold house tour says leaking pipes should be fixed by a plumber or other qualified professional. That correction is separate from the cabinet and floor repair. Fixing the leak does not by itself tell you whether the cabinet base or the floor needs anything beyond ordinary cleaning.
The cabinet box itself — the base, toe-kick, shelf and back panel — is a separate scope. Depending on how your kitchen was built, the wood-repair trade or a cabinet specialist may be the right fit; ask which one applies to your cabinet rather than assuming either way.
The floor covering under and around the cabinet toe-kick, and the subfloor beneath it, is a third scope again. Soft floor: when does the repair involve the subfloor? walks through that question in more depth. Once the plumbing source is confirmed corrected, the next question is whether the wood is ready to be closed back up; what to ask after a leak is fixed covers that handoff. A commercial kitchen or break room has the same three scopes, plus a fourth question about who can authorize access while the space is in use.
Compare the three scopes before comparing bids
| Component | What a written scope should state | Who addresses it |
|---|---|---|
| Active leak (supply, drain, disposal or dishwasher line) | Source found, corrected, and confirmed by the plumber | Plumber |
| Cabinet base, toe-kick, shelf, back panel | Which material is affected, the removal boundary, and the finish match | Cabinetry or wood-repair trade |
| Floor covering and subfloor near the cabinet | Whether the covering is reused or replaced, and whether the subfloor is reviewed separately | Flooring trade, with the wood-repair trade for the subfloor |
| A commercial kitchen or break room | Who authorizes access, and whether the area is taken out of use during the work | Property manager, coordinating each trade above |
Put the opening and the stopping point in writing
Before work begins, ask for a scope that states exactly what will be opened — the cabinet base alone, or also the flooring edge beneath it — and what the finish includes: a new toe-kick, a matched cabinet finish, replaced shelf liner, or the wood repair only, with finish left to you.
Ask what happens if the opened area shows more than expected, such as subfloor damage extending past the cabinet's footprint. A workable scope states that this kind of discovery pauses the job for a written update and your approval, rather than assuming the original boundary still applies. What should a revised scope explain? covers what that update should include.
Close the file the way you opened it
When the work is finished, ask for a short written closeout: what material was removed and replaced versus cleaned and reinstalled, confirmation from the plumber that the water source was corrected and tested, and dated photos of the opened cabinet base and floor before everything was closed back up. If the floor covering trade provided separate finish or matching documentation, keep that with the rest of the file rather than assuming one document covers all of it. A practical closeout checklist walks through what else to keep.
Questions before you approve the work
Does fixing the leak mean the cabinet is fine now? Not necessarily. A corrected leak stops new water from arriving; it does not tell you whether the cabinet base, back panel or subfloor already absorbed enough to need repair. Those are separate questions for the relevant trade to answer.
Can one proposal cover the plumbing, the cabinet and the floor? Some companies coordinate more than one trade, and some do not. Either way, ask for the scope to name each piece separately — source, cabinet material, floor covering and subfloor — so you can tell what each part actually includes.
What if the cabinet looks fine but the floor nearby looks swollen or stained? Treat that as its own question rather than assuming the cabinet is the cause; the floor covering and the subfloor underneath it have their own separate review.
Every kitchen, cabinet and plumbing layout is different, and the right next step depends on the actual property, the cabinet construction, plumbing access and who is available to look at it. Find your local Steady Craftsman team to confirm property fit, the affected component, access and availability before you commit to a repair.
Sources
- EPA: Text Version of the Mold House Tour. Names a leaking kitchen-sink pipe as a plumber's repair; it does not address cabinet, subfloor or flooring repair scopes.
- USDA Forest Products Laboratory: Wood and Timber Condition Assessment Manual. Describes visual inspection together with other examination techniques for assessing in-service wood; it is a general technical reference, not a kitchen-specific guide.