Aureobasidium pullulans in Washington homes
The pink-to-black yeast-like resident of wet surfaces
What this species signals about a building
Aureobasidium thrives on repeatedly wetted non-porous and painted surfaces — the classic organism behind stubborn dark staining on caulk lines and window gaskets. It signals surface-wetting patterns: condensation, splash zones, and ventilation shortfalls.
Where Washington buildings feed it
Marine west coast west of the Cascades: long wet season, low drying potential. Western Washington's wet season punishes marginal flashing details; crawl spaces stay damp for months without intervention.
Read those two paragraphs together and the assessment map draws itself: this organism grows where its moisture requirement is met, and Washington's climate and housing stock determine where that requirement gets met most often. That intersection — not a generic national checklist — is where instruments should go first.
What remediation requires
Clean or replace colonized caulk and gaskets, then change the wetting pattern: ventilation runtime, squeegee habits in showers, and condensation control at windows. Replacing caulk without changing the moisture pattern restarts the clock.
Starts cream or pink and matures to shiny black; commonly the dark growth on bathroom caulk, window gaskets, and painted sills.
- Months of rain with minimal drying windows
- Crawl space moisture
- Window and siding envelope leaks
Washington questions
Where does Aureobasidium pullulans typically show up in Washington homes?
The organism's requirements don't change by state — it grows where its moisture threshold is met. What changes is where Washington buildings meet that threshold: months of rain with minimal drying windows Combined with the local housing stock (western washington's wet season punishes marginal flashing details; crawl spaces stay damp for months without intervention), that's where an assessment should look first.
Does finding Aureobasidium pullulans mean something different in WA?
Mostly a surface and moisture-pattern indicator rather than a hidden-reservoir marker. Persistent recurrence after cleaning is the meaningful finding — it means the wetting pattern continues. In Washington, weigh that signal against the state's dominant moisture drivers — the species tells you about the water, and the local climate tells you where that water most likely came from.
Who handles Aureobasidium pullulans contamination in Washington?
Remediation requirements are set by the contamination, not the species name: clean or replace colonized caulk and gaskets, then change the wetting pattern: ventilation runtime, squeegee habits in showers, and condensation control at windows. We match Washington households with providers vetted on containment discipline, fine-particle competence, and independent verification — matching is free for households.
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