Conducive conditions are circumstances that unnecessarily attract wood destroying organisms to the home. Perhaps the most common such conducive condition, that takes place right in front of the homeowner's eyes, is vegetation or plants growing against the wood structure of the home.
Circumstances that can lead to problems with wood destroying organisms (rot, ants, wood boring beetles, termites) are known as conducive conditions. Probably the most frequently seen conducive condition, to a home inspector, is vegetation growing over the roof or against the siding of the home. In Washington State, a state licensed inspector seeing vegetation against the home is mandated to describe it as a condition conducive to attracting wood destroying organisms. This specific conducive condition can attract not only insects but it can lead to rot, also known as wood decay fungi.
Insects, such as carpenter ants, are prone to using vines as pathways onto or into the home. The other concern is that the vines shelter the home so moisture collects and the siding or roof does not dry, or it takes a very long time to dry. A moist environment will contribute to rot since rot fungi thrives in damp conditions.
If you are planning to sell your home, or just want to keep it in good condition, the best advice is to trim vines so there is about a foot of space between the siding and the vegetation. If you really do not want to do that, because you love the look at your house, then at least try to trim the plants so a few inches of clearance exists between vegetation and the home. Even a gap of three or four inches will keep insects from establishing a freeway to the home. And, if you can establish a few inches clearance, for drying, that is certainly better than no clearance at all. In a related matter, always keep soil off the siding and other structure at the home. Basic guidelines call for eight inches, to a foot, of clearance from soil up to the siding or other structure.
