Todd from Manuels NFLD looked under his siding and discovered that the nails holding the siding were rusting away.
In very damp climates, like Canada's two coastal regions, walls tend to get wet, and stay wet. In other areas of the country, the climate gives them more of a chance to dry out. Todd's vinyl siding was nailed right up against the sheathing and the house wrap was not sealed at all of its joints. That keeps the nails wet enough long enough to start rusting, and is probably causing damage to the wood as well. A more forgiving system is to put house wrap over the sheathing, then strap it with 1x3's and then put on the siding. This creates both a drainage layer behind the siding, and a ventilation space that can speed up drying on the occasional day that Newfoundland's horizontal rain let's up. Increasing the drying potential of a wall is the key to success in difficult climates.