Moisture and available nutrients allow growth on or within a surface layer.
Evidence supporting it
No strong confirming clue has been added yet.
Evidence weakening it
No direct contradiction is active yet.
Deterministic building intelligence
Follow the clues.
Follow the clues.
Reduce the uncertainty.
HouseSymptoms ranks likely causes from timing, location, weather and distinguishing evidence. The score is a transparent fit index—not a remote diagnosis.
21 diagnostic profiles31 failure fingerprints32 visual patterns
Active regional intelligenceGlobal baselineNo regional layer is active. Results use the global knowledge graph.
No terminology overrideSelect a regional pack to localize building language.
Open regional pack →Active profile
Black spots around a window
Compare microbial growth, soot deposition and repeated condensation at cold frames or reveals.
See0evidence clues active
Transparent cause ranking
What currently fits—and why
Fit index compares this profile’s evidence. It is not a probability and does not prove a hidden condition.
Framing or a conductive element lowers the interior surface temperature in a repeated pattern.
Evidence supporting it
No strong confirming clue has been added yet.
Evidence weakening it
No direct contradiction is active yet.
Moisture generation exceeds removal for the current temperature and air exchange.
Evidence supporting it
No strong confirming clue has been added yet.
Evidence weakening it
No direct contradiction is active yet.
Most useful missing evidenceYes, windows are often wetRepeated window wetting points to excess indoor vapor.+
Airborne particles collect preferentially at cold or high-airflow patterns.
Evidence supporting it
No strong confirming clue has been added yet.
Evidence weakening it
No direct contradiction is active yet.
Other questions still available
Is condensation also present?
Repeated wetting is the central environmental clue.
