Main Index

Siding and Cladding Problems

Generic Problems

Problem: Premature deterioration.

Siding can deteriorate prematurely (Figure 1) when moisture is present in the wall assembly. Fungi destroy wood fibers and promote the corrosion of metal siding and fasteners.

Cause: Condensation resulting from air leakage / Inadequate drying potential.


  • Prevent the flow of warm, humid air into the exterior wall, where it can condense on the back face of cooler siding. Install an effective, continuous air-barrier system to minimize the flow of any airborne water vapor.

Provide a vapor barrier on the warm side of the wall assembly.

lp siding deterioration

Figure 1 - Deterioration of lap siding