What Are Exterior Wall Coatings?

Exterior wall coatings are specialised coatings designed to protect and enhance the exterior walls of buildings. These coatings offer numerous benefits, including weather resistance, durability, and aesthetic appeal. They are a significant investment for homeowners and property managers, providing long-term protection against the elements and reducing the need for frequent maintenance.

Types of Exterior Wall Coatings

Acrylic Coatings

Composition: Acrylic coatings are water-based and consist of acrylic polymers, pigments, and additives.

Benefits: Acrylic coatings offer excellent adhesion, durability, and colour retention. They are also relatively easy to apply and clean.

Applications: Acrylic coatings are commonly used on a variety of surfaces, including timber, masonry, and stucco. They are well-suited for residential and commercial applications.

Pros & Cons:

Pros: Durable, colourfast, easy to apply and clean.

Cons: May not be as resistant to extreme weather conditions as other types of coatings.

Elastomeric Coatings

Composition: Elastomeric coatings are rubber-based and contain elastomeric polymers, pigments, and additives.

Benefits: Elastomeric coatings are highly flexible and can bridge cracks and imperfections in surfaces. They offer excellent weather resistance and waterproofing.

Applications: Elastomeric coatings are ideal for surfaces that experience movement, such as older buildings or those in areas with extreme temperature fluctuations. They are often used on stucco, concrete, and masonry.

Pros & Cons:

Pros: Highly flexible, excellent waterproofing, good for bridging cracks.

Cons: May be more expensive than acrylic coatings.

Silicone Coatings

Composition: Silicone coatings are based on silicone polymers, pigments, and additives.

Benefits: Silicone coatings offer exceptional weather resistance, breathability, and durability. They are also resistant to mould and mildew growth.

Applications: Silicone coatings are excellent for exterior walls in harsh climates. They are commonly used on masonry, stucco, and concrete.

Pros & Cons:

Pros: Excellent weather resistance, breathable, mould and mildew resistant.

Cons: Can be more expensive than acrylic or elastomeric coatings.

Stucco Coatings

Composition: Stucco coatings are typically a mixture of cement, sand, and water. They are applied in a wet form and then allowed to dry and harden.

Benefits: Stucco coatings provide a durable, fire-resistant, and low-maintenance exterior finish.

Applications: Stucco coatings are commonly used on residential and commercial buildings, particularly in Mediterranean climates.

Pros & Cons:

Pros: Durable, fire-resistant, low-maintenance.

Cons: Can be prone to cracking if not applied correctly.

Cement-Based Coatings

Composition: Cement-based coatings are made from a mixture of cement, sand, and polymers. They are applied in a wet form and then allowed to dry and harden.

Benefits: Cement-based coatings are very durable and offer excellent waterproofing properties. They are also resistant to abrasion and impact.

Applications: Cement-based coatings are frequently used on concrete, masonry, and stucco surfaces.

Pros & Cons:

Pros: Very durable, excellent waterproofing, resistant to abrasion and impact.

Cons: May not be as aesthetically pleasing as other types of coatings.

Maz Nazzimi, professional exterior painter at Dupaint Sydney offers this expert tip: “If you have an older building or a structure that experiences significant movement, elastomeric coatings are an excellent choice. Their flexibility allows them to adapt to expansion and contraction without cracking or peeling.”

Benefits of Using Exterior Wall Coatings

Protection

Exterior wall coatings provide a crucial layer of protection for your building, safeguarding it from a variety of environmental threats:

• Weather Resistance: These coatings act as a barrier against rain, snow, sun, and wind. They protect your walls from the damaging effects of moisture, UV rays, and harsh weather conditions.
• Mildew & Algae Resistance: Many exterior wall coatings are formulated to resist the growth of harmful organisms such as mildew and algae. This helps to maintain the integrity of your walls and prevents unsightly discolouration.
• Moisture Barrier: These coatings create a moisture barrier, preventing water from penetrating the wall and causing damage. This is particularly important in areas with high rainfall or humidity.

Aesthetics

Beyond protection, exterior wall coatings enhance the aesthetic appeal of your building:

• Colour Options: A wide range of colour choices and finishes are available, allowing you to express your personal style and create a unique look for your home or building.
• Texture: Different textures can add depth and dimension to your walls, enhancing their visual appeal.
• Renewed Look: Exterior wall coatings can refresh and revitalise the look of an older building, giving it a new lease on life.

Other Benefits

Exterior wall coatings offer several other advantages:

• Energy Efficiency: Some coatings have insulating properties that can help to improve your building’s energy efficiency. This can lead to lower energy bills and a reduced environmental impact.
• Reduced Maintenance: These coatings extend the life of your walls and reduce the need for frequent repainting. This translates to significant cost savings and less time spent on maintenance.

Factors to Consider When Choosing a Coating

Choosing the right exterior wall coating for your building requires careful consideration of several key factors:

Location

The climate in your location will significantly influence the type of coating you choose. For example, areas with high rainfall or humidity will require coatings with excellent waterproofing properties. Similarly, areas with intense sunlight like in Sydney, will need coatings that offer good UV resistance.

Building Materials

The type of wall material you have will determine the best coating solution. Different coatings are designed to adhere to specific materials, such as timber, masonry, stucco, or concrete.

Desired Finish

Select colours that complement your building’s design and reflect your personal preferences.

Consider the desired texture. Smooth finishes provide a sleek look, while textured finishes can create a more rustic or modern aesthetic.

The sheen level (e.g., matte, satin, gloss) will impact the overall appearance and reflectivity of the coating.

Budget

The cost of exterior wall coatings can vary significantly depending on the type of coating and the quality.

Consider the cost of applying the coating. Professional application often increases the overall cost, but it ensures a proper and long-lasting application.

Maintenance Requirements

Choose a coating that requires minimal maintenance and cleaning.

Select a coating known for its durability and longevity to reduce the frequency of repainting and repair.

By carefully considering these factors, you can choose the most appropriate exterior wall coating for your building, ensuring it receives the protection, aesthetic appeal, and long-term value it deserves.

Application Process & Preparation

Applying exterior wall coatings requires a methodical approach to ensure a successful and long-lasting finish.

1. Preparation of the Wall Surface: The first step is to properly prepare the wall surface. This involves:
   1. Cleaning: Thoroughly removing dirt, grime, loose paint, and any other contaminants.
   2. Repairing: Addressing cracks, holes, or other imperfections in the wall surface.
   3. Priming: Applying a primer to create a smooth, even surface for the coating to adhere to.
2. Application Techniques: The application technique depends on the type of coating and the surface:
   1. Spraying: Spraying is often used for large areas and can provide a smooth, even finish.
   2. Rolling: Rolling is suitable for smaller areas and can create a textured finish.
   3. Brushing: Brushing is a more traditional method and is often used for detailed areas or corners.
3. Drying Time and Curing Process: Allow sufficient time for the coating to dry completely. The curing process involves the coating hardening and reaching its full strength. Drying and curing times vary depending on the type of coating and environmental conditions.

Important Considerations

DIY vs Professional:

• DIY: Applying exterior wall coatings yourself can be a cost-effective option. However, it requires skill, experience, and attention to detail to achieve a professional finish.
• Professional: Hiring a professional painter ensures proper preparation, application, and curing of the coating. This can save you time and effort and ensure a long-lasting and aesthetically pleasing result.

Safety Precautions:

• Always wear appropriate safety gear, including gloves, eye protection, and a respirator mask, when applying exterior wall coatings.
• Ensure adequate ventilation during application and drying.
• Follow the manufacturer’s safety instructions for the specific coating you are using.

Maintenance & Durability

Proper maintenance and care will extend the lifespan of your exterior wall coatings and ensure your building remains protected and aesthetically pleasing for years to come.

Cleaning and Repair

Regular cleaning is essential for maintaining the appearance and performance of your exterior wall coatings. Here are some guidelines for cleaning:

• Frequency: Clean your walls at least once a year, or more often if needed, depending on the climate and environmental conditions.
• Cleaning Solution: Use a mild detergent solution and a soft brush or sponge. Avoid harsh chemicals or abrasive cleaners that could damage the coating.
• Rinse Thoroughly: Rinse the walls thoroughly with clean water to remove all traces of soap and dirt.

Over time, your exterior wall coatings may require minor repairs:

• Cracks or Chips: Small cracks or chips can be repaired with a matching paint or coating.
• Peeling or Flaking: Areas of peeling or flaking should be scraped clean and then repainted or recoated.

The lifespan of exterior wall coatings varies depending on the type of coating, the quality of the application, and the environmental conditions:

• Acrylic Coatings: Typically last 5-10 years.
• Elastomeric Coatings: Can last 10-15 years.
• Silicone Coatings: Offer exceptional durability and can last 15-20 years or longer.
• Stucco Coatings: Can last 20-30 years or more with proper maintenance.
• Cement-Based Coatings: Known for their exceptional durability and can last 20-30 years or more.

By following these maintenance guidelines and choosing a high-quality coating, you can ensure your exterior walls remain protected, visually appealing, and require minimal upkeep for many years to come.