Serpula lacrymans (Dry Rot)
Pest Instructor Solomon Hess
11/12/2025
Biology & Lifecycle:
Brown rot fungi, such as Serpula lacrymans (dry rot), decompose wood by breaking down cellulose while leaving behind brown, crumbly lignin. These fungi reproduce via spores and spread through thread-like hyphae. Growth accelerates in wood with a moisture content above 20%.
The Brown rot, Serpula lacrymans (aka Dry rot) causes wood to shrink, darken, and crack into small, cubical-shaped pieces known as “cubical fractures”
Habitat & Habits:
Serpula lacrymans thrives in damp, poorly ventilated spaces like crawl spaces, basements, around plumbing leaks, and areas with inadequate drainage. Infected wood becomes darkened, cracked in a cube-like pattern, and loses structural strength. Advanced decay can cause floors to sag and beams to fail.
Food Sources:
Brown rot fungi feed primarily on cellulose in wood, attacking structural timbers, floor joists, sill plates, and subflooring.
Entry Points:
Fungal spores are ubiquitous in the environment and colonize wood when moisture levels remain consistently high due to leaks, condensation, poor ventilation, or ground contact.
Control & Exclusion Tips:
- Repair leaks and improve foundation drainage
- Install vapor barriers in crawl spaces
- Ensure adequate ventilation to reduce humidity
- Replace damaged wood and treat surrounding areas with fungicide
- Four Seasons Pest Solutions can assess moisture issues and recommend solutions to prevent brown rot and preserve your home’s structural integrity
And remember, it’s okay to live among pests… but you don’t have to live with them!
Four Seasons Pest Solutions, Inc.