Acrylic vs Silicone Roof Coating

Roof coatings are a popular way to fix leaks and extend the life of an existing roof without replacing it. Among all options, acrylic and silicone roof coatings are the most commonly used. While they may look similar once applied, they behave very differently, especially when it comes to water, durability, and long-term performance.

This guide explains the difference between acrylic and silicone roof coatings in simple terms, so you can choose the right one for your roof.

What Is Acrylic Roof Coating?

Acrylic roof coating is a water-based coating made mainly from acrylic polymers. It is usually white and reflective, helping reduce roof temperature. Acrylic coatings are widely used because they are affordable, easy to apply, and environmentally friendly.

They work best on sloped or well-draining flat roofs where water does not sit for long periods.

What Is Silicone Roof Coating?

Silicone roof coating is a moisture-cured coating made from silicone solids. Once it cures, it forms a rubber-like, waterproof layer. Silicone is especially known for handling standing water without breaking down.

It is commonly used on flat or low-slope roofs that have drainage issues or ponding water.

Key Differences Between Acrylic and Silicone Roof Coating

Water Resistance

This is the biggest difference between the two. Acrylic roof coating is water-resistant, but not fully waterproof in all situations. If water sits on an acrylic-coated roof for long periods, the coating can soften, bubble, or wear down over time.

Silicone roof coating, on the other hand, is fully waterproof. It does not break down under standing water, which makes it a better option for flat roofs with ponding water.

Durability and Lifespan

Acrylic coatings usually last 5 to 10 years, depending on thickness, weather, and maintenance. They may need reapplication sooner in harsh climates.

Silicone coatings typically last 10 to 20 years. They resist UV rays and weather damage better and do not chalk or crack easily.

Reflectivity and Energy Efficiency

Both coatings are reflective and help reduce heat. Acrylic coatings are very reflective when new, but they can lose reflectivity faster as they collect dirt.

Silicone coatings also reflect sunlight, but they tend to hold onto dirt more, which can reduce reflectivity unless cleaned occasionally.

Maintenance and Repairs

Acrylic roof coatings are easier to repair and recoat. New acrylic layers bond well with old ones, making future maintenance simple.

Silicone coatings are harder to recoat. Many materials do not stick well to cured silicone, which can limit repair options later unless special preparation is done.

Cost

Acrylic roof coating is usually cheaper upfront, making it attractive for budget-conscious projects.

Silicone roof coating costs more initially, but its longer lifespan and superior waterproofing often make it more cost-effective over time.

Acrylic vs Silicone Roof Coating (Quick Comparison)

Can You Put Silicone Roof Coating Over Acrylic?

Yes, you can apply silicone roof coating over an existing acrylic coating, but only if the roof is properly prepared. The surface must be clean, dry, and firmly attached to the roof. Any loose or peeling acrylic must be removed before applying silicone.

In some cases, a primer is recommended to improve adhesion. Skipping surface preparation can lead to poor bonding and early failure.

Is Acrylic Roof Coating Waterproof?

Acrylic roof coating is not fully waterproof in the same way silicone is. It does a good job of shedding rainwater, but it does not handle standing water well. If water stays on the roof for long periods, acrylic coatings can soften and degrade.

For roofs with good drainage, acrylic works well. For roofs with ponding water, silicone is the better choice.

Which Roof Coating Should You Choose?

Choose acrylic roof coating if your roof has proper drainage, you want a lower upfront cost, and you prefer easy future recoating.

Choose silicone roof coating if your roof is flat, has ponding water, or you want the strongest waterproof protection with a longer lifespan.

External Reference

For general roof coating standards and best practices, you can refer to the National Roofing Contractors Association (NRCA): https://www.nrca.net

Final Thoughts

Both acrylic and silicone roof coatings are good products when used in the right situation. Acrylic is affordable and easy to maintain, but it struggles with standing water. Silicone costs more but offers superior waterproofing and long-term performance.

The best choice depends on your roof’s slope, drainage, budget, and long-term goals.