Where can I find information on mold and mildew of structural wood members?

The USDA Forest Service Wood Handbook pages 17-2 through 17-5 contain material on wood mold and mildew.
Publication link: Forest Service Wood Handbook.

The Build Green: Wood Can Last for Centuries report explains why wood decays, alerts the homeowner to conditions that can result in decay in buildings, and describes measures to prevent moisture-related damage to wood.
Publication link: Build Green: Wood Can Last for Centuries.

Mold and Moisture in Homes

Mold. It’s all around us.  We use mold to make cheese, process wine, and produce helpful drugs such as penicillin.  We also see unwanted mold in places such as damp basements.  Mold even exists on human bodies.  So, one might ask, what’s causing the current questioning about mold?  There’s no easy answer to that question.  However, there are some reasonably straightforward facts about how and when mold might start to grow in or around your home.


FACT: Spores, the dormant form of mold, are in the air we breathe, the soil in our gardens, and in and around virtually every part of our homes.

FACT: Mold spores will not actively colonize, or grow, without adequate supplies of food, air, and moisture.  In typical homes, the normal control of moisture levels prevents colonization of mold spores.

FACT: A properly constructed building envelope is designed to keep the inside of your home dry (including the interior and concealed building spaces) to stop mold spores from becoming active.    This building envelope also insures that wood products quickly achieve and remain at a moisture level that will not support mold growth.

FACT: Except for cases in which moisture is artificially introduced into the structure (for example, by interior water leakage, unusually high interior humidity levels, or penetration of the building envelope), mold will generally not become active in your home.

FACT: All mold spores can not be permanently eradicated by cleaning or disinfecting.  While cleaning can remove spores present at the time, it will generally not protect surfaces against mold spores that arrive after cleaning.

FACT: Conditions that are sufficiently moist to support active mold colonization are also sufficiently moist to degrade the materials in your home.  For example, wood products may start to decay, metal products may begin to rust, and other products may begin to deteriorate.

Techniques to minimize mold problems in your home

Control build-up of moisture within your home.  Install and use ventilating fans in kitchens and bathrooms.  Be sure that fan exhausts are ducted to the outside.  Use dehumidifiers where necessary, but don’t allow the dehumidifier to become a source of mold itself.  Insulate any ducts which pass through unheated attic or crawl spaces.

If mold or mildew begin to grow in or on any part of your home, find the source of moisture intrusion and stop it.  If moisture intrusion has been occurring over time, hire a professional to examine the structure to determine if any permanent damage has occurred.