Can I install Vinyl siding over the existing wood cladding?
Yes, but the wood siding needs to be in good shape. Water damage and rot must be addressed so as not to compound the problem by covering it up with new siding. Mold and fungi are a little trickier. Mold and fungi become dormant when their moisture source is removed, or when the moisture content falls below 20% moisture content, the spores are still viable and decay will begin again if exposed to moisture and temperature conditions. Topical fungicides tend to be short-lived. If you are certain the exterior moisture (rain, sleet, snow) is the only culprit for the decay, then cladding the house with a foam board product and/or furring strips and vinyl siding can be a practical option. If the moisture source cannot be identified, isolated and corrected, the safest route is to follow with regard to occupant health and contractor liability is to remove the wood cladding before installing new siding.
