To Homeowners, Developers, Contractors, Architects, Engineers and Real Estate Professionals:
If you are involved in the purchase, sale, management, construction or development of real property, you need to know about the issues with a fungus that is capable of destroying entire homes and buildings from the ground up!
This fungi is called Meruliporia Incrassata (“Poria”) and it eats wood like a cancer.
(The above photo shows rear portion of a home destroyed by Poria.)
“Poria” is a brown rot fungus, and as such, the decayed wood will look just like the decayed wood from any other brown rot fungus (the ones that rely on leaks for their required moisture such as window or roof leaks).
There are distinctive characteristics that can be used to identify “Poria” in the field. The first of these is the water conducting rhizomorph. (See Above) The second is the spore producing ‘fruiting body. (See Below)
What Can You Do About Poria Once it Infects Your Building?
Unfortunately, “Poria” is located in soil and once it is allowed to make the transition from the soil beneath the building to the building’s wood members, the only remedy is cut out the effected wood, install new wood and then create a barrier so the “Poria” cannot re-infect the wood in the future.
What Can You Do to Keep Poria From Infecting Your Building?
Fortunately, “Poria”’ is also very sensitive to dehydration (drying out), so the key is to avoid construction details that allow the rhizomorph to reach the structure. Compliance with the building codes with respect to proper clearances between wood and soil conditions are extremely important in preventing infestation by “Poria”. Most of these construction issues listed below are the result of the failure to follow the building code which allows “Poria” to infect buildings by allowing the following conditions to exist:
Soil allowed to come in contact with wood;
Stucco installed below soil grade:
Siding allowed to extend below soil grade;
Inadequately vented crawlspace (not properly vented, inadequate earth-wood clearance);
Cracks in perimeter foundation and slab on grade allowing migration of rhizomorphs to reach wood;
Planters placed against exterior wall with soil contaminated with ”Poria”;
Sprinklers or other water source creating ‘ponding’ near the home (related to poor grading);
Failure to slope the soil away from the building causing excessive moisture and avenues for Poria infestation;
Failure to maintain proper clearance between landscaping and wood members of the structure.
All of these conditions allow “Poria” to enter the structure without experiencing a drying environment. Therefore the key to avoiding “Poria” damage is to avoid (or repair) the construction details that allowed entry in the first place. Although this appears to be a simple solution in principle, it can be expensive and require extraordinary retrofitting of the site conditions to implement for an existing structure.
In order for Homeowners, Developers, Contractors, Architects, Engineers and Real Estate Professionals to determine the existence of “Poria” or the construction details which can lead to “Poria” infestation, a comprehensive inspection by qualified construction and fungus specialists must be undertaken. Therefore, when there is purchase and sale of residential or commerical property or if there is any construction or remodeling of a building which will involve movement of soil, there must be an inspection by knowledgeable construction and fungus inspectors to eliminate the potential for “Poria” infestation.