Moisture negatively impacts the structural integrity of
houses. Research documenting this damage dates back many
years but became more prevalent with the progressive tightening of residential houses that began in earnest during the
energy crisis of the 1970s (Sherwood and TenWolde 1982).
The existence of moisture problems in any home depends
upon several factors, including the quantity and duration of
condensation, the building materials in place, indoor and
outdoor temperatures, and the ability of the home to expel
excess moisture (NAHB 1987).
Moisture damage includes wood decay, paint failure on
finished surfaces, buckling of sheathing or siding, and the
reduced effectiveness of insulation (Sherwood and TenWolde
1982). A Canadian field survey of 201 moisture-damaged
houses (VanPoorten 1983) reported buckling and warping of
siding, high moisture readings in sheathing, mold and mildew
within the house, high moisture readings in wall cavities,
severe window condensation, window frame damage, and
mold and mildew as well as high moisture readings in attic
The Canada Mortgage and Housing Corporation Builders’ Series (CMHC 1988) noted the following problems with
regard to moisture in wall cavities: rotting of structural
members, deterioration or staining of exterior sheathing, deterioration or staining of exterior siding, warping of wood
siding, efflorescence or spalling of brick or stone, peeling of
paint on exterior siding, corrosion of metal fasteners, mold and
mildew on structural wall members and on exterior sheathing,
and water staining on interior finishes. The report goes on to
identify other problems relating to moisture such as condensation on walls, ceilings, windows, and other surfaces.
In the mid-eighties, a study was conducted in Champaign,
Illinois (Rose 1986). In part, the study attempted to look for
any connections between observed moisture and its sources.
Results showed a relationship between moisture damage and
moisture sources and also that construction practices, not lifestyle, were mostly responsible for the moisture problems. In a
separate study, Angell (1988) concluded that the indoor relative humidity levels of 46% - 61% found in a group of panelized homes in Minnesota resulted in problems that included
condensation on most storm windows, mold growth on indoor
window sashes, condensation staining on walls and ceilings,
wet basement rim joists, and general siding moisture stains.
Anderson and Sherwood warned homeowners about condensation problems in a bulletin prepared for the Department of
Agriculture as early as 1974.
The full research study can be found here: