moisture control in walls
It is a myth that installing vapor
barriers is the most important step for controlling moisture in walls.
Vapor barriers only retard moisture due to diffusion, while most moisture
enters walls either through fluid capillary action or as water vapor through
All climates require these moisture control steps:
Place a termite shield, sill gaskets, or other vapor-impermeable membrane
on the top of the foundation wall. This action will prevent moisture from
wicking into the framed wall from the concrete foundation wall by capillary
- Install a polyethylene ground cover on the earth floor of houses
with crawl spaces and slope the ground away from the foundations of
- Install a continuous vapor barrier, if your climate needs one (see
map on this page) that has a perm rating of less than one.
Preventing rain penetration
Causes of rain leaks through exterior walls include improper installation
of the following:
Wind-driven rain can also penetrate the exterior finish. To enhance protection
against rain penetration, create a drainage plane within the wall system
of the home.
- Siding materials
- Poor-quality flashing
- Weatherstripping or caulking around joints in the building exterior
(such as windows, doors, and bottom plates).
AND MOISTURE CONTROL