Roof Coatings Guide: Types, Advantages, and Disadvantages

Roof Coatings Guide: Types, Advantages, and Disadvantages

A coated roof

While most homeowners don’t think much about their roof, it’s one of the most important components of your home. Your roof protects you and your most valuable assets from rain, snow, UV rays, and more.

When it’s time for a new roof, most homeowners default to replacing it completely. But did you know coating your existing roof can extend its lifespan for a fraction of the cost?

In this guide, we’ll cover everything you need to know about roof coatings – the types, applications, pros, cons, costs, and more. Whether you’re looking to squeeze a few more years out of your existing roof or want to learn about coatings for a new roof install, you’ll find all the details here.

Types of Roof Coatings

There are different types of roof coatings to choose from for both commercial and residential roofing applications. The most common options include:

Asphalt Coatings

Asphalt roof coatings are an inexpensive option made from asphalt, a petroleum byproduct. These coatings are suitable for low-slope roofs and are designed to protect and preserve the roof surface. Asphalt coatings offer good water resistance, but they have a shorter lifespan and less flexibility than other coating options.

Acrylic Coatings

Acrylic roof coatings are made from acrylic polymers mixed with pigments and fillers. They provide good protection and reflectivity. Acrylic coatings are water-based, flexible, and durable. They are an economical choice but do not last as long as silicone coatings. Acrylic coatings work best on smooth roofing substrates.

Silicone Coatings

Silicone roof coatings are based on silicone polymers that provide excellent water resistance. The coatings are seamless, durable, and flexible. They hold up well in extreme weather while also allowing the roof substrate to expand and contract. Silicone coatings are more expensive than asphalt or acrylic coatings but provide long-lasting protection.

Polyurethane Coatings

Polyurethane roof coatings form a thick, rubber-like protective layer. Polyurethane has excellent adhesion, weather resistance, and longevity. It provides effective moisture protection and can be used to coat irregular roof shapes and textures.

There are two main types of polyurethane coatings used in roofing: aliphatic and aromatic.

  • Aliphatic Polyurethane: Typically used as a top coat, aliphatic polyurethane offers superior UV resistance, meaning it holds its colour for a long time and resists dirt accumulation. This makes it ideal for long-term performance and aesthetics.
  • Aromatic Polyurethane: More cost-effective than aliphatic, aromatic polyurethane is often used as a base coat. While not quite as UV resistant, it still provides excellent protection and can be a good choice for areas with less sun exposure.

Applications of Roof Coatings

Roof coatings can be applied to a variety of roof types to extend their lifespan, improve waterproofing, and add reflective properties. Some of the most common applications include:

Low Slope Roofs

Roof coatings work extremely well on low slope roofs (roof slope lower than 2:12), including those with built-up, modified bitumen, and single ply membranes. The coatings add a seamless waterproof membrane across the entire roof surface for improved water shedding. They also add durability and UV resistance compared to the base roofing material alone.

Metal Roofs

Metal roofs can develop rust and corrosion over time. A protective roof coating will bond to the metal surface to help prevent rust and deterioration. The coatings also add a reflective surface to dramatically reduce roof temperatures.

Modified Bitumen

On modified bitumen roofs, also known as “mod-bit”, liquid coatings provide seamless protection across the roof compared to the seams and joints inherent in mod-bit. This improves waterproofing and longevity.

Single Ply Membranes

Single ply membranes such as PVC, EPDM, and TPO are susceptible to punctures, UV damage, and seam failure. Liquid-applied roof coatings form a fully adhered protective layer over single ply membranes for improved durability and weather protection.

What Are the Advantages of Roof Coatings?

Roof coatings offer several key benefits compared to leaving your roof uncoated or doing a full roof replacement. Some of the main advantages of roof coatings include:

Prolong Roof Life

Applying a roof coating can extend the life of your existing roof by up to 20 years. Coatings form a protective barrier that prevents UV rays, extreme temperatures, moisture, and other environmental factors from deteriorating your roof. This allows you to get more life out of your current roof instead of having to do a costly full replacement.

Energy Efficiency

Reflective roof coatings are designed to reflect sunlight and solar radiation. This can lower the surface temperature of your roof by up to 50°F. With a cooler roof, your air conditioner doesn’t have to work as hard to maintain comfortable indoor temperatures. This translates into lower energy bills during warm weather.

Lower Costs Than Full Replacement

Roof coatings offer a significant advantage in terms of upfront costs compared to a full roof replacement. While the exact price depends on factors like the size and material of your roof, coatings generally fall within a more budget-friendly range. This allows you to extend the lifespan of your existing roof without incurring the expense of a complete tear-off and reinstallation.

Reflective Coatings Reduce Heat Absorption

Roof coatings contain reflective pigments that help reduce heat absorption. On a hot day, an uncoated dark roof can reach temperatures of 170°F. With a reflective coating, your roof stays cooler, reducing stress on roofing materials and leading to longer roof life. Reflective coatings also reduce the urban heat island effect.

What Are the Disadvantages of Roof Coatings?

Roof coatings can be a great solution for extending the life of your roof, but they aren’t perfect. Here are some potential drawbacks to consider:

  • Limited lifespan: While they can extend the life of your roof, roof coatings themselves don’t last forever. They will eventually need to be reapplied, and depending on the material, this could be every 5-10 years. 
  • Preparation Required: Your roof surface needs to be properly cleaned, repaired and prepared before applying a coating. This adds time and labour costs.
  • Not for Severely Damaged Roofs: If your roof is severely worn out or has extensive damage, a coating will not be able to adequately repair it. You’ll need a full roof replacement instead.
  • Ponding water issues: Some roof coatings, particularly acrylics on flat roofs, can struggle with ponding water(areas where water accumulates). This can lead to premature coating failure and promote mould growth.
  • Dirt accumulation: Certain roof coatings, like silicone, can attract and hold dirt. This can reduce reflectivity (increasing energy costs) and make the roof look less appealing.

How to Choose a Roof Coating

Choosing the right roof coating for your building or home is an important decision that requires some research and consideration. Here are some key factors to take into account when selecting a roof coating:

Roof Type and Condition

The roof surface material will impact what types of coatings can be used. Asphalt, metal, concrete, and single ply membranes all have roof coating solutions, but each has its own specific requirements.
The current condition of the roof is also important. A roof in good condition will require less intense preparation and a simpler coating application. A worn or damaged roof may need repairs and specialised coatings.

Climate Factors

Climate impacts roof coating performance. In cold climates, ice and water shield coatings are recommended. In hot and sunny areas, reflective white coatings help reduce heat gain.
Additionally, consider local weather challenges like moisture, high winds, and UV exposure when choosing a coating, as these elements influence the necessary properties of the coating, such as elasticity, durability, and overall longevity.

Budget

Acrylic elastomeric roof coatings tend to be the most budget-friendly option, while silicone, polyurethane, and hot asphalt coatings are premium options.
Lifespan also varies, with the premium options generally lasting longer than the cheaper options. The upfront cost should be weighed against the expected lifespan.

Desired Benefits

Key benefits like energy efficiency, leak protection, or chemical resistance will point you towards certain coating materials. Prioritise the needs of your roof when selecting a coating.

Aesthetics

Roof coatings come in a variety of colours, especially white or other light reflective tones. This can impact curb appeal and exterior style.
Textured coatings can help enhance grip or hide imperfections. These offer visual options beyond basic smooth coatings.

What to Consider When Choosing a Roof Coating Contractor

When it’s time to hire a roof coating contractor, you’ll want to do your research to find someone experienced and reputable. Here are a few tips for choosing the right coating contractor:

  • Look for experience with roof coating projects. Make sure to ask potential contractors how many coating jobs they have completed, the types of coatings they have experience with, and examples of past coating projects. You want a contractor that is well-versed in roof coatings.
  • Check reviews and references. Any good roofing contractor should be able to provide reviews from past customers, along with references you can contact. Check reviews on sites like Google or Yelp and reach out to references to get a sense of the contractor’s work quality, timeliness, customer service, and more.
  • Ensure proper licensing and insurance. Your contractor should carry all required licences for your area and have general liability insurance as well as workers’ compensation. Ask to see copies of their licences and insurance certificates. This protects you in case there are any injuries or property damage

Extend the Life of Your Roof with Anglia Decor

Looking to extend the lifespan of your roof, improve energy efficiency, or simply give your roof a new lease on life? Anglia Decor provides solutions tailored to your specific needs. 

Don’t let the selection process overwhelm you. Reach out to us today for a consultation, and let’s find the right roof coating to safeguard and improve your property..

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