Kilz Stain-Blocking Latex Water-Based Primer

Kilz Stain-Blocking Latex Water-Based Primer

Many do-it-yourself homeowners associate the Kilz brand of paints and primers with ultra stain-blocking abilities, akin to a crack unit of paint-bearing SEALs you call upon to get the difficult job done. If you merely want to put color on a wall, you use regular acrylic-latex paint. But if you have a problem, you use Kilz or other brands of job-specific stain-blocking sealers and primers.

Does Kilz paint live up to its reputation? Is it easy to work with, spreadable, and most importantly, does it effectively block those problem stains?


With a well-established reputation spanning over four decades, Kilz paint has been in the business of covering up rust stains, mold, mildew, and unfortunate color choices in millions of homes. Kilz paint is a water-based latex primer and sealer. Available in quart, gallon, and 5-gallon sizes, Kilz comes in basic white and can be used as is or tinted to the color of your choice. 

Kilz is not meant to be the eventual finish coat. Its sheen is a dull flat-matte comparable to any other kind of primer. The sheen is not the smooth, suede-like type of flat finish you might find with a flat interior wall paint. Instead, its chalky finish is meant as a base for other paints. Tinted Kilz is only meant to bring this lower base coat closer to, or even exactly matching, the top finish coat, reducing the number of color coats needed.

Since Kilz is water-based, it has very little smell and is comparable to the smell of regular acrylic-latex interior paints. Because of this tolerable smell, Kilz is conducive to working in even small, enclosed spaces.


Kreb's Units, or KU, is a standard for measuring the viscosity of liquids. To illustrate, thin honey's viscosity starts at 106 KU and goes upward from there. Kilz has a viscosity rating of between 95 and 105 KU. Kilz 2 has the same viscosity of Kilz Ceiling Paint, a purposely thick product. Kilz 2 mixes well and spreads well, but not exactly smooth. 

Kilz' tendency to smear can be counteracted by loading the brush with just a bit more paint than you might with regular paints. Care must be taken, though, to avoid leaving drips and streaks that harden on the surface. These can be difficult to remove, even by sanding them down.

Stain and Color Blocking

Kilz paint does block surface colors and stains more effectively than regular acrylic-latex paint. However, if you are expecting a miracle, one-coat solution to all of your finish woes, Kilz 2 and most other paint brands cannot supply this solution. While you may be able to cover up a light color with only one coat of Kilz 2, more intense stains will require multiple coats. Heavily streaked surfaces (rust, mildew, etc.) may require up to three coats of Kilz to block the streaks entirely.

It does help to thoroughly machine-mix the Kilz and begin using it within a few hours of purchase. Or you can use an inexpensive drill-driven paint mixer to draw up the solids from the bottom of the can and thoroughly disperse them. Another tip is to use thick nap roller covers, as these pick up more Kilz in the tray. Thick nap covers do produce a bumpier surface, though this should not be a problem if you are painting brick, blocks, or other textured masonry materials.


Kilz paint cleans up easily with warm water. As with any paint, it does help to clean brushes with a paintbrush comb. Since Kilz paint is thicker than normal paint, you may need to slosh the brush underwater for an extra minute or two, but the brush will eventually come clean.

Similar Products

It is worth noting that Kilz 2, which is considered the flagship Kilz product, is not the only game in town. Over the years, Kilz' parent company Masterchem has developed other Kilz paints for niche uses.

Kilz Max is significantly more expensive than Kilz 2, often costing twice as much, but Kilz Max excels at covering up the worst of stains; it even manages to lock in noxious odors from cigarettes, pets, and fireplace smoke. Another product, Kilz Klear, is transparent and is especially well-suited for same-color repainting. Finally, severe exterior stains such as tannins, bleeding stains, and graffiti can be covered up with the oil-based Kilz Complete product.