» The difference in these types of finishes is the aggregate size for the most part, although every type of finish can be applied a number of ways. The following are considered industry standard finish references; Fine Float, Float, Textured, Machine Applied-Dash, Smooth and Semi-Smooth.

Stucco types and texture descriptions:

16/20 is the coarsest and considered the industry standard finish.
Standard single application Float finish or scratch and double-same day two coat application.
Textured-Skip trowel (Knock Down) is a same day two coat application with a float finish background.
Machine Applied-Dash finish, is a scratch and double-two coat, allowed to dry between applications.

20/30 is considered a high-end residential or commercial level finish.
Fine Float finish, is a scratch and double-same day two coat.
Skip Trowel and Free Style finishes, are same day two coat applications with trowel chatter or float finish background.
Light or Extra Fine Machine Applied-Dash Finish, a scratch and double-two coat, allowed to dry between applications.

Santa Barbara Mission Finish (SBMF) contains only # 30 silica sand.
Smooth, Semi-Smooth, Cat Face, Mission, and Free Style Finishes, are a scratch and double-same day two coat application with trowel chatter or float finish background.

» Acrylic finishes utilize paint technology with aggregates added that can be trowel or spray applied with the appropriate equipment. Acrylic finishes can be applied over portland cement base substrates and EIF Systems using an approved grade.

Stucco Color Coat is a natural cement-based material; acrylic finish is a synthetic man-made coating. Stucco cures to a hardened state while acrylics dry to a hardened state.

Acrylics dry from the outside in and can be sensitive to environmental conditions. Air circulation is as important for drying as the temperature, especially in humid conditions. Cement stucco finish "cures" as opposed to drying.

Cement finish coats are a nominal 1/8 inch thick and have the ability to fill small imperfections in the base coat. Acrylic finishes have very little ability to compensate for surface irregularities.

For acrylics or cement finish, the portland cement plaster base coat must be cured before applying the finish, but a longer cure time is beneficial. It gives the building additional time to "find itself" or settle before the finish coat is applied.

Based on the type of acrylic finish and the texture of the existing surface, a skim coat of Stucco Level Coat may be required, a color matched acrylic primer may be recommended or in some cases color coordinated acrylic primer may be required.

Water Repellency:
Traditional cement Stucco Color Coat, like all cement products, will absorb surface moisture and darken when wet. Acrylics will repel surface moisture, but moisture will pass through as a vapor. Acrylic finishes should never be mistakenly used as a method to "seal" the building from water intrusion. Properly applied Portland cement plaster base coat will keep moisture out while remaining vapor permeable. It is advisable that all finish coat materials, including paint, be a "breathable" membrane.

Acrylic finish should never be used on horizontal surfaces or other areas susceptible to ponding water. An advantage of acrylic finish is that they maintain their color when wet which is a consideration in wet climates.

Flexibility:
Cement based finish coats are not flexible and hairline cracks will often transfer through the finish. Acrylic finish coats are more flexible when initially installed and tend to hide minor hairline cracking in the first year or so. However, acrylic finish coats are not considered an elastomeric. After exposure to the sun, the acrylics tend to harden and hairline cracks may appear at a later time.

Maintenance:
Both Stucco Color Coat and Acrylic finishes are relatively low maintenance and both can be coated with appropriate materials when a change of color is desired. Acrylic finishes have proven to work well over 30 years. Stucco finishes have proven to work well for many decades, well over 75 years in some cases.

Conclusion:
Both Stucco Color Coat and Acrylic finishes have strong points and some limitations. Designers and owners should review a complete list of features to determine which finish is most appropriate.

» The Rain will stain; protect your Stucco Color Coat with a water repellent. Pro-Tect water repellent is effective at repelling stains due to water born material on Stucco Color Coat finishes that are in acceptable condition, helping protect wall against water saturation. Wait until fresh Stucco Color Coat has cured before applying a Pro-Tect water repellent.

Truly sealing Stucco Color Coat is not the best option, be sure to use a "breathable" material.

» Parex USA Inc. is a manufacturer of stucco products, not a contractor or installer of stucco.

» A certain amount of cracking in stucco basecoats (which has simply transferred through the finish) is normal. Certain fine or smooth textures accentuate cracks in stucco, while heavier textures tend to hide stucco cracks. Although not all cracks are objectionable, cracks in stucco acceptable to one person might be unacceptable to another person.

Cracks can appear in stucco regardless of texture. Building codes and ASTM C926 do not call for a required hardness (PSI) for Portland Cement Plaster. Minor cracking at the corners of doors and windows and other stress points is reasonable and should be anticipated, color coat stucco is not structural; it is a decorative finish.

Cracks that appear on the surface of stucco walls are usually caused by conditions within the wall structure. Some of these conditions include shrinkage of wood based (green or wet) framing members, thermal expansion and contraction, ground movement and soil expansion and contraction, shear panel flexing, water intrusion (which can cause wood based framing members and sheathing to swell) and a variety of other jobsite conditions. Plaster does not shift outward of its own volition after it is stabilized, it must be pushed out of alignment by some significant force.

Cracks may also appear in stucco due to shrinkage (hydration, rapid loss of moisture, wind and high temperatures) can cause checking cracking. Freshly applied stucco basecoats should be moisture cured and should be protected against rapid drying from high winds. In extreme conditions moisture curing of the finish with a fine mist of clean water may also be necessary.

Although stucco assemblies do sometimes crack, it does not mean that the stucco has failed or was installed incorrectly, it simply means that stresses from outside sources are present, and have relived themselves in the plaster membrane.

Patching of hairline cracks 1/16" or less is not recommended as it will detract from the natural beauty of the stucco and will serve no useful purpose. In most cases the repair of them will be more apparent than the crack itself. The patching of larger stucco cracks can be completed with the same finish material and color used for the existing finish.

» As stucco cures some of the water it contains evaporates. This causes the stucco to shrink slightly. As it shrinks, small cracks called "check cracking" may appear. Although some check cracking is normal, applying stucco finishes in hot; dry weather tends to increase check cracking in stucco. Stucco Color Coat will normally dry and set the same day, during periods of hot and or dry weather conditions, a light spray (mist) of clean water is recommended over the stucco finish. Except for severe drying conditions, the wetting of finish coat should be avoided; this is not the base coat prior to application of the finish coat. If desired, an application of Fog Coat or Allegro II Cement Coating can be used in an attempt to disguise this.

» Stucco cures through Hydration, Stucco finishes unlike stucco base coats (which require moist curing by wetting) cure by available moisture-humidity. Except for severe drying conditions, the wetting of finish coat should be avoided. Stucco Color Coat will normally dry and set the same day, during periods of hot and or dry weather conditions, a light spray (mist) of clean water is recommended over the stucco finish. If the stucco dries out too quickly during the curing process the stucco will dry soft. Some of the causes of soft stucco include wind, high temperatures, and no moisture in the substrate. Hot and windy weather may cause water to evaporate from new stucco too rapidly.

If the stucco does not hydrate properly and does not get hard, the surface may be moist cured to facilitate hydration. In addition, a dry substrate will draw moisture out of the color coat and stop the hydration process.

» Some natural-appearing color variation is inherent to Stucco Color Coat. Among the many factors that influence color in stucco applications is substrate suction and hydration (i.e., weather): Stucco Color Coat normally uses available moisture to cure.

The same stucco material may result in a different color in a humid environment than in a dry area or in shady versus sunny areas. This is particularly true with a sand float or sand finish-texture because the water needed to float the finish can cause some color to be washed out.

Excessive color variations may be the result of dissimilar substrates, variations in the suction, inconsistency of water content in mix, varying thickness of the finish, or weather conditions during and after application.

Fog Coat may be applied to the surface to even the color on the stucco finish, although it is not recommended for smooth-dense surfaces. Allegro II Cement Coating is the product designed for changing the color of stucco including smooth-dense surfaces.

» Fog Coat may be applied to blend the color of textured Stucco Color Coat finishes or revitalize older stucco finish with the same color. It is a portland cement base product that can be recoated with stucco color coat in the future. Fog Coat may be applied to stucco finish as soon as the finish has dried. The color level may be adjusted darker in the field as necessary to more closely match the existing color, by adding a small amount of additional pigment from a color pack of the same color.

Note: Fog Coat is NOT recommended for smooth-dense, painted, sealed, wood or metal surfaces. Although properly applied Fog Coat can be painted if necessary, it is not to be applied to paint or used as a primer for paint.

Allegro II Cement Coating is neither Fog Coat nor Paint, Allegro is something between the two and is the product designed to change or in some cases provide surface color, it also can be recoated with stucco color coat in the future.

Allegro II Cement Coating is a cost-effective, durable and long-lasting colored coating that can be applied to portland cement surfaces such as: stucco (including smooth Santa Barbara Mission Finish), Concrete block/Concrete masonry unit (CMU) and Precast concrete.

Note: Allegro is NOT recommended for application over painted, sealed, wood or metal surfaces. Although properly applied Allegro Cement Coating can be painted if necessary, it is not to be applied to paint or used as a primer for paint.

Paint is a coating used to cover many surfaces including stucco in some cases. Proper preparation and pH levels are key to the success when painting a stucco wall. Paint may be applied 28-days after the stucco has been applied. If this is not the case, the pH level and preparation recommendations of the paint supplier should be followed.

» These microscopic organisms are part of the natural life cycle of organic matter, including decay and composting of landscaping plants and other mulches. Excessive moisture in flowerbeds, shrubs, mulch and other organic materials creates ideal growing conditions for these organisms.

To prevent or minimize it by eliminating the excess moisture; be sure irrigation systems are not directed against walls and keep plants trimmed back to allow ample light and air circulation.

Mold stains are removed using a mild solution of TSP (Tri Sodium Phosphate) and water. Using a plastic brush gently scrub the surface and rinse thoroughly. If stubborn stains persist try a solution of bleach and water (1-part bleach to 5-parts water) using the same brush and rinse technique.

» Efflorescence, is soluble minerals appearing on the surface of portland cement based materials.

Efflorescence needs 3 things for it to occur.
-There must be soluble salts in the material
-There must be moisture to pick up the soluble salts, and carry them to the surface.
-Evaporation or hydrostatic pressure must cause the solution to move.

Note: If any one of these conditions is not there, efflorescence cannot occur.

Efflorescence in most cases, can be cleaned or least treated for coating over by spraying a 3:1 solution of water and distilled white vinegar to the pre-wet surface followed by thoroughly rinsing with clean water before drying. Some residual staining is normal; Fog Coat and Allegro II Cement Coating are very effective for covering this condition after cleaned or treated.

» First try scraping the stucco off the concrete. Then try using a mild solution of TSP and water brushed onto the surface and rinsed thoroughly. If unsuccessful try a 3:1 solution of water and distilled white vinegar to the pre-wet surface, using the same brush and rinse method, followed by thoroughly rinsing with clean water before drying.

» This may be colonies of mildew. These microscopic organisms are part of the natural lifecycle of organic matter, including decay and composting of landscaping plants and mulches. Excessive moisture in flowerbeds, shrubs, mulch and other organic materials creates ideal growing conditions for these organisms.

Prevent or minimize, it by eliminating the excess moisture: be sure irrigation systems are not directed against walls and keep plants trimmed back to allow ample light and air circulation. Remove these discolorations from stucco surfaces by applying household bleach to the pre-wet surface followed by thoroughly rinsing with clean water before drying.

Remember: always keep bleaches and other chemicals away from children, and ALWAYS use the proper safety equipment — including eye protection — when working with a hazardous substance.

» With proper application and under normal conditions, with minimal maintenance Stucco color coat will last many years, many applications have performed well over 75 years.

Conventional Refinishing methods: Re-stucco, stucco finish over existing stucco if not painted or sealed, a portland cement based skim or level coat such as Stucco Level Coat is recommended if the existing finish is textured.

If stucco color coat is the desired finish and the existing surface is painted, the paint must first be removed by sand blasting or other methods. It is recommended that the wall be coated with an acrylic bonder for proper adhesion of the new color coat.

Acrylic and Elastomeric Finishes can be applied to acrylic based painted surfaces that demonstrate good performance and adhesion and are not chipping, flaking or pealing, otherwise remove the paint with methods that result in no more than 10% of the paint remaining and apply a color tinted acrylic primer prior to the finish application. A leveling coat may be required for application of some finish levels over textured surfaces.

Allegro II Cement Coating can be applied to unpainted-unsealed stucco finishes for color change only, if the existing surface and texture are acceptable.

Although stucco, like other masonry surfaces, can be painted this is neither the best nor the most economical way to change color. Over time, paint tends to fade, chip and peel away from stucco walls.

If the finish has already been painted, simply recoating the surface with DPR or Elastomeric Coating can be effective for color change only.

Painting stucco finishes: Painting stucco although not normally recommended, should be delayed to most importantly allow the stucco to reach a point where the pH changes from its high of about 12.4 to approximately 8 or 9 although Stucco is not fully cured for approximately 28 days.

» Most stucco colors darken slightly over time unlike painted surfaces that fade, chip and/or peel, stucco color is "integral." This means stucco color extends through the entire stucco layer instead of only the surface

Properly maintained exterior stucco can remain attractive for many years with only minimal changes. However, exposure to dust, dirt and pollution over time can change its color. An application of Fog Coat in the same color for finishes other than smooth or Allegro II Cement Coating for color change on all finishes including smooth is the best way to revitalize stucco.

» Locate the color code number from your builder or applicator and contact the Parex USA Color Department. Contact your local Distributor in your area. Remember, stucco colors can darken slightly as they age. Be sure to consider this when purchasing new stucco to match existing finish. You might need a slightly darker shade of the same color for older stucco. We recommend conducting a color test to compare the new color with the old before applying the stucco to the entire project.

» This is not recommended, a minimum 3/8" brown coat of Portland cement plaster applied to the wall prior to the Stucco Color Coat reduces the possibility of the grout lines telegraphing through the Stucco Color Coat. The brown coat properly prepares the surface making it more receptive to the color coat application; additionally it levels the wall for a straighter and more attractive wall.

If the block, brick or concrete wall has been painted or sealed, either remove the paint/sealer or mechanically attached lath, then apply a portland cement plaster base coat, moist cure and allow to dry prior to the Stucco Color Coat.

» This is usually caused by the stucco coming in contact with soil and extended exposure to moisture which allows the salts and minerals contained in soil and cement based products to migrate to the surface. This can eventually deteriorate and/or cause delamination of the stucco. The most common causes are: water from Sprinklers continually soaking the wall or improper site drainage (water draining toward the wall). Moisture in the soil or water sitting at the base of the wall is traveling up the wall in a wicking action; due to a lack of Weep Screed at the bottom of stud framed stucco walls prior to early 1970's construction.

This condition is common in older buildings and for this reason, the Federal Housing Authority (FHA) determined the need for "weep screed" a separation device as a remedy in new construction. Repairing the condition is relatively simple although in most cases, only temporary. A separation of the stucco and the soil followed by repair would be the only permanent solution. See Technical memo: Stucco Wall Base Deterioration at Soil for additional information.

» A wide variety of custom colors are available from our color sample lab upon request. Some colors cannot be replicated with cement-based stucco. These are usually very dark or high intensity colors. Precise matching of existing stucco color is sometimes difficult. Environmental conditions and age will cause variations in the original color.

Fog coating may be necessary to blend in new and old color coat. Depending on the actual finish type and color level, stucco can darken with age, due to moisture, dirt, environmental contamination and pigment migration.

» Under normal conditions a bonder is not a required although the application of an acrylic bonder does offer improved adhesion and basecoat suction control, and when applying color coat stucco over an existing or repaired surface acrylic bonder can provide in a more consistent color result. Acrylic Bonder & Admix is recommended when applying Stucco Color Coat over Parex USA Stucco Level Coat.

However if you plan to re-stucco over a smooth surface, the surface should first be etched and then apply an acrylic bonder immediately prior to the new finish.

Over a previously painted surface, the paint must first be removed by sand blasting or other methods. It is recommended that the properly prepared wall be coated with an acrylic bonder for proper adhesion of the new color coat.

» Color coat stucco should be applied at a nominal thickness of 1/8" thick. However color coat may be applied up to 1/4" thickness maximum, when using a coarse aggregate blend and multiple applications such a Heavy Machine Applied-Dash finish, for instance our 16/20 blend may be applied thicker than our 20/30 blend and Santa Barbara Mission Finish blends.

» Color coat finishes (just like stucco basecoats) should be applied to natural breaks in the wall in one application to avoid unsightly joint lines and discoloration.

» The use of accelerators in stucco color coat finish products is not recommended. However, on cold days, warm water used to mix the products will help speed up the set naturally. Applying the material immediately after mixing them without re-tempering will allow for a quicker set as well.

» Exterior Stucco Color Coat is designed for application over cement plaster brown coat, it will not properly bond to drywall or other common interior surfaces without extensive surface preparation. Parex USA Select Finishes or DPR Acrylic Finishes can be applied to properly prepared interior surfaces.