Aspate of news stories about celebrities whose houses have been damaged by mold have put most home buyers and owners on alert for signs of this moisture-induced problem. But there is a much more damaging house-attacking organism most owners have never heard of — Meruliaporia incrassatta or “Poria,” a voracious wood eating fungus some scientists believe is making significant inroads in Southern California. In addition to the structural threat Poria poses to a home, it can be financially devastating if not promptly identified and remedied, because most residential insurance policies do not cover the damage it causes.

Poria lives naturally in the forest. There it plays a vital role transforming dead trees into compost that nourishes the next generation of growth. Poria is uniquely adapted to do this: it sprouts water-conducting tentacles, known as rhizomorphs, that allow the fungus to transfer water from as much as 30 to 60 feet from a source to the wood Poria consumes. Rhizomorphs can be as thick as a tree root or as flat as paper — otherworldly capabilities that make Poria a miracle in the forest but a nightmare in residential settings. There, Poria can eat wooden foundation supports and walls out from under a home in several months, often undetected. Wood beams that appear intact can actually be hollow and paper thin, eaten from the inside up to the surface by Poria’s rhizomorphs.

Few legal remedies are available to the homeowner who discovers Poria underfoot. Most home insurance policies exclude coverage for mold and fungus, which includes Poria. As fast as attorneys have found legal arguments around these exclusions, insurers have amended policy terms to plug these gaps. Recent standard policy terms allow insurers to avoid paying the hundreds of thousands of dollars it can cost to remedy Poria’s damage and leave homeowners liable for costly repairs. Most insured California homeowners are not covered for the expensive rebuilding necessary when Poria invades a home.

In the published case of Jordan v. Allstate Insurance Co. (2004) 116 Cal.App.4th 1206, the appeal court reversed a trial court decision denying homeowner Mary Jordan the right to go to trial on her claim to recoup damages caused by Poria. Jordan contended the loss was covered under her home insurance policy’s additional coverage for entire collapse caused by “hidden decay.” The appeal court held Jordan was entitled to go to trial on her claim her loss was covered under the policy. But the result in the case of Sapiro v. Encompass Ins., 221 F.R.D. 513 (N.D. Cal. 2004) is more typical. There, the federal court held that damage caused by moisture, fungi, and poor workmanship was excluded under the homeowner’s policy.

Home buyers may have a legal recourse if Poria is discovered within the deadline for filing a lawsuit against sellers and the professionals involved in a home purchase. However, to hold a seller liable the buyer usually must prove the seller had actual knowledge of the Poria infestation. Other possible defendants include real estate agents, pest inspectors and home inspectors, if their reports and disclosures failed to accurately alert a buyer to conditions that are associated with Poria.

Standard inspections may overlook Poria. Although this wood-destroying fungus has long been a problem in Southern California, many real estate professionals are uninformed about the conditions that make a building vulnerable to it and the signs that it is attacking a home. Pest inspectors are the only professionals involved in the typical residential sales transaction who are obligated by law to detect and identify Poria in their reports. However, Poria is sufficiently uncommon that many pest inspectors have never seen it and are unable to identify clues to its presence.

Unlike pest inspectors, home inspectors are not responsible for identifying Poria, but are obligated to call attention to unsound construction conditions — some of which facilitate Poria’s access to a home. Wood that comes into contact with dirt, wood supports built below grade, inadequately ventilated foundations, persistent moisture under or around the foundation, or landscaping that pushes dirt against a house wall, are all conditions that provide easy entry points for Poria’s rhizomorphs. Such conditions should be noted on a written home inspection report because they do not comply with good construction practices and may violate codes.

While repairs may be very costly, damage from Poria can be thoroughly remediated and reoccurrence prevented if proper construction techniques are used. Hence, the fact a house was attacked by poria in the past does not mean it will have problems in the future, if appropriate repairs are undertaken.

Home buyers and owners who believe Poria may be damaging their home must quickly investigate whether the infestation was hidden by the seller or professionals, in order to have the best chance to preserve their right to a legal remedy. Prospective defendants should become knowledgeable about Poria, and make certain full disclosures are made by buyers and the professionals assisting with a home sale.

Pamela Lawton Wilson is a shareholder at the Downtown law firm of Sullivan, Wertz, McDade & Wallace, where she represents clients in litigation matters, including real estate disputes, ADA defense, political law compliance and civil writs and appeals.