Q: I inherited a 250-year-old wooden bench passed down from my great-great-grandfather in Wales, a region known for its cold damp climate. The bench is in good condition and quite sturdy except for some small odd indented disfigurations. The piece is now in the living room of my apartment in the Northeast and is kept dry and unused for sitting. When I received the bench I was told it might have dry rot. What exactly is dry rot and how can I tell if it is present? Can it spread? I live in a restored, turn-of-the century apartment with many aged wood surfaces and antique furnishings.

A: "Dry rot" is really "wet rot" that has dried out. Wood decay or wood rot may have occurred at some time in the past. It required exposure to chronic damp conditions over a period of time. When those conditions cease to exist, the wood dries out and the decayed wood is sometimes called "dry rot". Decayed wood crumbles to the touch and has little strength or structural integrity. In the case of a bench it would not bear significant weight. There are laboratory analyses that can determine the presence of wood decay and determine its severity.

Wood decay cannot spread, it can only occur when the conditions conducive to growth exist. Our world is full of mold spores that can cause wood decay, but it will only occur when the temperature and available moisture is present for growth. In other words, the wood floors and antiques should be fine unless your house is damp.

Wood types also vary widely to their susceptibility to fungal growth that causes wood decay. Cypress, cedar, red wood and teak are examples of wood that are very resistant to fungal decay. Most wood commonly used such as oak, fine and pine are moderately resistant to wood decay. Resistance to wood decay is based on the presence and level of natural occurring chemicals (terpenes) found in wood that inhibit microbial growth.

If you are concerned with mold spores being present in the wood that may cause allergies or might have some other heath impact, you can clean (HEPA vacuum the surface, possibly sand) and treat the wood to remove existing fungal growth and coat the wood with a clear fungal encapsulant that will minimize the possibility of fungal spores being released from the bench. All cleaning should be done in a well ventilated area.

Mark Goldman, Senior Air Quality Scientist, EFI Global, Inc.

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