Chaetomium globosum
The cellulose specialist that signals chronic saturation
What it tells you about the building
Like Stachybotrys, Chaetomium requires sustained saturation of cellulose materials, making it forensic evidence of long-duration water intrusion — frequently found in the same assemblies as Stachybotrys and often preceding it in succession. It aggressively degrades the materials it colonizes, so its presence often accompanies structurally compromised drywall and soft wood.
Why it matters in assessments
Chaetomium globosum is one of the five HERTSMI-2 marker species, weighted for its strong association with significantly water-damaged buildings. Meaningful levels in dust are a strong argument for envelope investigation rather than surface cleanup.
What remediation requires
Removal of colonized materials is non-negotiable — the substrate is typically degraded beyond salvage. Because it marks chronic moisture, the assessment must identify a long-running water pathway, and verification should confirm that pathway is closed.
Cottony colonies maturing from white to grey to olive-brown, with characteristic lemon-shaped fruiting structures visible under magnification.
- Long-term wet drywall and sheathing
- Chronically damp wood framing
- Paper and cardboard in wet storage
- Behind wallpaper in leak zones
State editions
Where this species shows up depends on where local climate and housing stock meet its moisture requirement. Read the local picture:
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