DeHaven Construction Company

"Specializing in Stucco, Stucco Repair, Interior Painting, Exterior Painting, Texture Coating (Texcote™) & Elastomeric Coatings"

Paint - A Vapor Barrier?

Installation installed without vapor barrier

Installation installed with vapor barrier

Certain paints can and do act as vapor barriers.

There are several types of vapor barrier materials other than paints. All act to prevent moisture vapor from penetrating into the surface between interior and exterior walls.

A normal family will generate several gallons of moisture a day through cooking, showering, washing clothes, etc. In cold weather, the absence of a vapor barrier, actually allows moisture to pass through the walls as it tries to reach equilibrium with the cold, dry air outside. This moisture vapor will condense in the stud space between interior and exterior walls and can eventually lead to rotting of the siding or peeling of the exterior paint. This is due to the fact that warm air can hold considerably more moisture than cold air. In freezing weather, this condensation may turn to ice crystals, melting later to saturate the siding.

Insulation, installed without a vapor barrier, will not prevent this condition. The moisture vapor will condense in the stud space and saturate the insulation. Since wet insulation conducts heat more rapidly than dry insulation, the efficiency of the insulation is drastically reduced.