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Is Your Home’s Stucco Streaky or Blotchy?

Is Your Home’s Stucco Streaky or Blotchy?

Have you received a notice from your HOA stating that you have to paint the exterior of your home? Many homeowners’ in North County San Diego have gotten these letters stating they need to paint your home or be fined. A majority of these homes are less than 10 years old. How is it possible that the exterior paint is in such bad shape so quickly? The answer is that it’s not paint on their home, it’s “Color Coat.”

What is color coat and what is the difference from paint?

In 1963 a company named Merlex created pigmented stucco called Color Coat. In the past 15 years builders have increased the use of this product. By using tinted stucco, the builder is able to speed up construction and cut costs by eliminating the step of painting the exterior of the home. From a builders perspective this is a great product. Using Color Coat is fast and cheap compared to traditional paint. The company states that by using their product, homeowners never have to paint again. If that is true, why are entire subdivisions being forced by the HOA to paint their homes?

Color Coat stucco has to be mixed and applied in a very specific manner. Any slight divergence from instructions will result in product failure. Examples of these failures include, non-uniform suction of the base coat, color contamination, pigment migration, visible joint and scaffold marks, uneven drying of color coat, efflorescence, stains, cracking, blotchy or spotty color, delamination, and soft stucco.

This look is mislabeled as “Old World, Aged or Tuscan.” Don’t be fooled by décor terminology. The construction industry calls this look “Poor Craftsmanship.”

Variables that cause failure

  • Substrate density: WHEN APPLYING COLOR COAT TO DIFFERENT SECTIONS OF THE HOME, EACH AREA WILL NOT MATCH BECAUSE VARIED MIXTURES OF THE PRODUCT. If the substrate density varies, the color coat finish will vary in intensity. Set times, water mixing ratio affect consistency.
  • Color coat hydration: (i.e. weather) DEPENDING ON THE WEATHER AT THE TIME OF APPLICATION, VARYING MOISTER ABSORTION WILL OCCUR RESULTING IN DISOLORATION, BLOTCHINESS AND STREAKING. The color coat uses available moisture to cure. The same stucco may take on a different color in a very humid environment than in a dry area.
  • Application technique: MANY TIMES MORE THAN ONE PERSON APLLIES THE STUCCO. THE APPLICATION STYLE MAY NOT BE SIMILAR. ONE PERSON MAY APPLY THE PRODUCT THICKER OR THEIR APPLICATION PATTERN MAY DIFFER. The applicator can influence the final color of the stucco assemble through application method, choice of tools, etc.

Color Coat vs. Paint in a Coastal Environment

These permanent coatings are thick and they don’t “breathe”, so to speak. This becomes a huge issue when applied to wood siding particularly. Trapped moister can result in internal structure wood rot. If a house does not have an interior vapor barrier, warm moist air migrates through the walls causing discoloration and moister pockets. It’s also common for entire sections of stucco to simply fall off. Because the material used for color coating is a Portland cement-based substance, it is porous. Once dry, it is able to actually absorb water, wreaking havoc on the finish and potentially peeling off the original stucco. In addition to water absorption, the porous surface is also subject to penetrating stains that will have to be recoated to hide. It is imperative for coastal San Diego homes to have finish coat that allows ventilation.

Latex paints will allow the transmission of water vapor. Developing mold is less likely when using exterior paint as opposed to tinted stucco.

Color Options

Color Coat comes in 30 colors. The majority of homes are varying shades of brown. Color pigments are mixed directly into the coating when color coating stucco. Because there is a maximum ratio of pigment to coating, darker colors may be difficult to achieve, limiting the homeowner’s exterior color options.

Standard Paint has a limitless amount of color choices. When using paint, homeowners have the option of thousands of standard colors, or they can have their own custom color created. The possibilities are endless.


Color Coat warranty states

“Merlex Color Coat Exterior Stucco is warranted to perform in accordance with the product specification when used according to application instructions on the label. This warranty is limited to and shall not exceed the total amount paid by the buyer for the product. In no event will Merlex Stucco, Inc. be liable for loss of profits, special or consequential damages in respect to any claim. The foregoing warranties are in lieu of all other warranties express or implied including those concerning fitness for a particular use.”

Let’s decipher the legal lingo. It simply states that the product has to be mixed and applied in a very distinct process and in precise conditions. Any variation will result on voiding all warranties. The product warranty overrides the contractor’s warranty. It states the manufacture is not liable for any damages. Simply put, THERE IS NO WARRANTY.

Paint has lengthy warranty period. Sherwin Williams’s products warranties range from 15 years to a lifetime warranty.


Remodeling projects such as window replacements cause challenges if color coat was originally used.

Match existing color coat is potentially impossible. For a seamless stucco patch, uniform texture, consistency, color and application technique must be duplicated.

Matching paint is simple. Even if the paint has changed due to age, matching the color is easy. Homeowners can scrape off a sample of stucco; take it to their local paint store and have it matched using a computer.

Color Coat can be a lasting, protective barrier for your home if applied properly. When builders use this product for mass production, emphasis is placed on reducing construction times and cost rather than quality and durability.

If you find yourself owning a house that has inconsistent colors, streaks and cracks, these flaws can be fixed. You can achieve an even finish and color by hiring a painting contractor to correct and improve the appearance of your home’s exterior stucco.

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If you are looking for a San Diego Stucco Contractor then please call 760-274-3373 or complete our online request form.