Each year, wood-decaying fungi can cause as much damage to structures as termites do. In fact, some damage attributed to termites was actually caused by wood-decay fungi because the moisture conditions favorable for fungi growth were not corrected.
Groups of Wood-Decay Fungi include:
- • Brown Rot The wood will usually become a brownish color and upon drying will shrink into small cubical pieces with cracks that run against the wood grain. The cubes are easily crushed into powder.
- • Water-Conducting Rot More commonly known as dry rot, this fungus produces papery yellowish-white fans and root-like cords which may be whitish to brownish to black. This fungus produces a brown-rot type of decay.
- • White Rot This fungus gives wood a bleached appearance, usually with black lines. Unlike the previous two fungi, white rot become stringy and spongy.
Wood-decay fungi require the proper combination of food, moisture, temperature and oxygen for growth.
- 1. Food – the fungi use the cellulose and lignin of plant cell walls as their food. As they break down the cell’s structure, they also decrease its strength, thus decreasing the wood’s strength as well.
- 2) Moisture – in order to grow, wood-decay fungi require the wood moisture content (or moisture in cell walls) to be at or about the fiber saturation point. This saturation point varies for most U.S. wood species, but is usually between 28-32%. If the saturation is below this point, the fungus is not dead, but it is inactive. Once the saturation level reaches its optimal percentage, the fungus will start to grow again.
- 3) Temperature – at cool temperatures, fungi are inactive or dormant. Most fungi attain optimum growth rates between 75-85˚F and are killed by brief exposures to temperatures between 105-150˚F.
- 4) Oxygen – decay fungi require as little as 0.05% of the oxygen found in air, therefore it is rarely a limiting factor. Fungal growth can be stopped by submersion in water or burial several feet deep in soil because of the lack of oxygen.
Fungi usually enter a structure as airborne spores. Another source would be through wood-to-ground contact and it is possible to bring in infested lumber during the time of construction or later. Regardless of the source, the optimal combination of these factors must exist before fungal growth can occur. Return to Top
The presence of non-decay fungi is a good indicator that conditions exist which may soon be favorable for wood-decay fungi.
Groups of Non-Decay Fungi include:
- • Sap-staining fungi (blue-stain fungi) These fungi produce colored thread-like strands deep within the wood. The stain is usually bluish, bluish black, gray or brown.
- • Surface-staining fungi This group is the molds and mildews. These fungi produce colorless threads within the wood and form colored spores at the wood surface which give a powdery or fuzzy appearance. The spores may be an array of colors.
- • White pocket rot (pock rot, white pocket, white spec) This fungus produces numerous small pits filled with white threads in the wood of living evergreen trees, usually Douglas firs. White pocket rot does not survive in wood products.
Identification of the type of fungus present in your home is the first step to a successful remediation and treatment. Inside the house you should check for settling or buckling of the floors, plumbing leaks, condensation from the AC unit and adequate attic ventilation. Outside look for proper ventilation, land gradation (away from the house), proper downspout locations and peeling or blistering paint. Underneath the house you should check for wet soil, standing water and damp foundation walls. Return to Top
Through our free inspection we will identify the type of fungus that is present, educate you on the type and course of action and eliminate all traces of the fungus.