Cladosporium species in Washington homes
The most common mold on earth, indoors and out
What this species signals about a building
Cladosporium dominates outdoor air in most climates, so its indoor presence is expected at background levels. The signal is pattern: concentrated growth on condensation surfaces — windows, registers, cold corners — points to humidity and thermal-bridge issues rather than bulk leaks.
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
Surface cleaning plus environmental correction: improve ventilation, address thermal bridging and window condensation, and control humidity. Recurring growth after cleaning means the condensation driver was not fixed.
Olive-green to brown-black colonies with a suede-like texture, common on surfaces as spotty growth rather than large mats.
- Months of rain with minimal drying windows
- Crawl space moisture
- Window and siding envelope leaks
Washington questions
Where does Cladosporium species 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 Cladosporium species mean something different in WA?
As a predominantly outdoor genus, Cladosporium contributes to the outdoor-species side of indices like ERMI. Elevated indoor growth matters more as a humidity diagnostic than as a water-damage marker, though heavy indoor amplification is still a condition to correct. 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 Cladosporium species contamination in Washington?
Remediation requirements are set by the contamination, not the species name: surface cleaning plus environmental correction: improve ventilation, address thermal bridging and window condensation, and control humidity. We match Washington households with providers vetted on containment discipline, fine-particle competence, and independent verification — matching is free for households.
FULL SPECIES FILE → Cladosporium species · DUST TESTING IN WA → ERMI & HERTSMI-2 in Washington
THIS SPECIES IN OTHER PRIORITY MARKETS → California · Colorado · Florida · Nevada · Texas
NEXT SPECIES IN WA → Alternaria alternata in Washington