What Primer to Use on a Poured Concrete Basement Wall

Acrylic Latex Primers

• Acrylic latex primers are often suitable for poured concrete walls when moisture intrusion is not expected to be a significant problem. That would be the case on homes in arid regions or in homes where the exterior wall is protected by a waterproof membrane. The acrylic latex film is compatible with the higher alkalinity and moisture content of the concrete because it is vapor-permeable and it will stay flexible during the concrete's temperature related expansion and contraction cycles.

Alkyd Primers

• Ordinary alkyd primers are also compatible with poured concrete, but with some important caveats. Painters are advised to wait at least four weeks after the wall has been poured for the moisture content and alkalinity to be released. In dry locales, the alkyd primer film will help serve as a vapor barrier that will assist the long-term adhesion of the topcoat. Alkyd primers contain a higher solvent content than latex paints, and painters should be aware of the resulting fumes that can build up in enclosed basement areas during the application process.

Block Filling Primers

• A block filling water-based primer is recommended for porous concrete, especially when hairline cracks are visible. This is a full-bodied coating that delivers less coverage per gallon than conventional paints, so it will be more expensive to use. It will, however, provide a highly uniform surface for the topcoat, which ensures even absorption and uniform sheen and color. Many block-filling primers are designed for use on damp walls, although they are not effective at blocking significant levels of hydrostatic pressure.

Waterproofing Paint

• Waterproofing paints block moisture and efflorescence that can migrate through concrete and cause ordinary paints to fail. In fact, a waterproofing paint is more effective at blocking water pressure than the concrete itself. A water-proofer is technically not a primer because it can also serve as a topcoat in unfinished basement areas. Unfortunately, water-proofers do not offer homeowners the same variety of color and sheen choices as conventional paints. For decorative purposes, the water-proofer best serves as a base coat that can then be primed with any latex primer and finished with ordinary interior paint.