Wood Rot: 

Wood rot is a very common problem that can show up on practically any home. Wood rot occurs when parasitic fungi consume the cellulose by injecting a digestive enzyme in the cells of the wood. So wood does not decay if it is protected from the fungi.  The fungi have to use moisture in the wood to circulate the digestive enzymes. Therefore the fungi attacks wood only if the moisture content of the wood is above 30 percent. Also the wood has to be free of toxic chemicals. Some woods have sap that is naturally toxic to fungi. Cedar and redwood are resistant to wood rot and are commonly used in areas where wood rot may be a problem. Other naturally resistant wood varieties include cypress and locust.  Wood preservatives are used to make wood toxic to fungi. Creosote has been used for many years to help prevent wood rot in railroad cross ties, and utility poles are treated with a chemical called pentachlorophenol. However, creosote and other chemicals applied to the surface do not penetrate very far into the wood, and the wood rot fungi will eventually infect and deteriorate the wood beneath the surface. Wood manufacturers have solved this problem by forcing chemical preservatives (chromated copper arsenate) into the wood with pressure. Pressure treated wood (also known as "wolmanized") is virtually invincible to wood rot fungus attack, especially when used above ground.  There are some minor disadvantages of pressure treated lumber. The chemical toxins can be released in a fire, and the toxic metals in the ashes from burned wood must be properly disposed. Treated lumber scraps should therefore not be burned. Pressure treated lumber usually has a slight green tint when new, and it will dry out, warp, and split just like most wood. It should be painted, stained, or otherwise protected from the elements to remain attractive.  Most homes have some wood siding, window frames, or wood trim that is not chemically treated to prevent wood rot. It may seem that this above-ground wood would be dry and impervious to wood rot fungi. Actually, that would be case if it always remained dry. However rain, humidity, plumbing leaks, and lawn watering can saturate the wood and make an inviting host to fungi.  The best prevention for wood rot is to eliminate the opportunity for moisture to enter the wood. Maintain good ventilation in crawlspaces and attics. Make sure rainwater cannot puddle on window sills, porch columns, decks, or other wood surfaces. Always be on the lookout for plumbing leaks and repair them promptly.  Your house is painted to be attractive, but one more important function of paint is to establish a moisture barrier to the wood. Carefully check wood window frames, siding and trim for cracked, peeling, or blistered paint. Sometimes the coat of paint appears intact, but is rippled or depressed. Often this is a sign of wood rot under the paint. Probe suspect areas with a screwdriver or ice pick to make sure the wood is hard.  It is a good idea to inspect the house frequently to find and repair wood rot before it becomes extensive. If the damaged area is not in structural wood and is small, say less than 40 percent of the piece of wood, it can usually be repaired. Remove all damaged wood, fill the void with epoxy wood filler, sand and refinish the wood. If the damage is more extensive, the wood will need to be replaced. An expert should evaluate structural wood damage.  Preventing wood rot is much easier, less time consuming, and less expensive than repairing an advanced case. If your home has wood rot or conducive conditions, call a home maintenance contractor or carpenter. If plumbing leaks or rainwater is causing wood rot, call a plumber or roofing contractor. [ Back to General Home Information ] Schedule Your Inspection Today