Siding material should not be chronically wet. We’ve talked about this with respect to grade level. It is also true where the bottom of the siding intersects a roof. The best practice is to keep the siding material 2 inches above the roof Most people settle for a 1 inch clearance. There are step flashings under the siding and roof so it’s okay to keep the siding above the roof surface.
Wood and wood-based products are particularly vulnerable to moisture wicking up into and damaging the siding. End grains of wood and cut edges of hardboard, OSB, and plywood draw moisture into the wood enthusiastically. It’s common to see siding deterioration along a roof/ wall intersection. Again, water damage to the siding and possibly to the structure behind are the implications.
Most sidings discolor if they are chronically wet. Paint may peel. Stucco may soften and crumble. Brick may crack and spall, especially if the moisture in the brick freezes. Efflorescence may develop on the brick.
As home inspectors, we pay close attention to these areas to help protect you and keep you informed during your home purchase.