Why Roof Coatings Are a Good Alternative to Roof Replacement
Roof coatings have numerous benefits. There are two types of roof coatings, acrylic, and silicone.
We compare them below, but both have these benefits:
- High reflectivity – Because they reflect infrared light, which we detect as heat, they keep roofs cool and reduce the cost of cooling your building. Their UV reflectivity greatly reduces damage to the roof.
- Cost-Effective – Both options are 10-20% cheaper than a new roof or roof replacement
- Quiet Installation – Roof coatings are installed over the existing membrane. Because no tear-off is required, disruptions to business are minimal.
- Eco Friendly – In addition to reducing energy costs, roof restoration keeps waste out of landfills. Low odors mean ventilation is not a concern.
Which is better? Acrylic or Silicon? Let’s compare their strengths and weaknesses.
Acrylic and Silicone Roof Coatings Compared
Acrylic Coatings – Strengths and Weaknesses
ACS workers place a polyester sheet on top of a layer of coating. They will then use brooms to press it into the coating and apply another layer of coating on top of that. This is a National Coatings acrylic coating to Cypress Apartments in San Jose.
Acrylic coatings balance affordability and performance.
This water-based solution is a cost-effective alternative to roof replacement.
Acrylic roof coating has many upsides including:
- exceptional durability,
- adhere to loose substrate unlike silicone,
- relatively fast and easy to install,
- withstands heavier foot traffic,
- and dirt doesn’t accumulate on them so they maintain their reflectivity.
Acrylic roof coatings have some downsides including:
- They lose mil thickness due to weathering, as evidenced by the chalky residue that builds up over time.
- They can take significantly longer to install than silicone.
- They usually don’t perform well in ponding water. Astec coatings do however provide a warranty against ponding water when applied at a sufficient thickness.
Silicone Coatings – Strengths and Weaknesses
Silicone coatings are the “Cadillac” of roof coating systems.
These coatings are stable, flexible, and can come with a twenty-year warranty. Silicone coating has numerous strengthens including:
- They are exceptionally durable.
- No primer required.
- One coat application.
- Lowest cost per applied square.
- 50+ yr warranty available.
- They don’t degrade from weather, and lose mils.
- They don’t get hard or brittle.
- Rapid installation.
- They work well in ponding water if the water stays for less than 48 hours.
- They conduct heat poorly.
- They are easy to apply. Just power wash, prime if needed(rarely), and apply coating.
- They are moisture-cured, so humidity can even promote their cure.
Silicone roof coatings have some downsides.
- They need a stable substrate to bond too so can’t be applied over gravel.
- They require a bleed block if applied to an asphalt roof.
- They are significantly more expensive than acrylic coating. This is offset by the need for fewer coats.
- They may pull away from edges and curl.
- They are very slippery when wet so shouldn’t be applied if maintenance people are going to access the roof.
- They don’t hold up well against foot traffic.
- They hold dirt, so they lose reflectivity over time.
- They are harder to re-coat because they are almost as slippery as Teflon.
- Removal can be difficult because they attach to substrate extremely well.
- They can be easily torn so they are installed with a fabric that compensates for their mechanical weakness.
A major consideration with silicone coatings is they are extremely slippery when wet and shouldn’t be applied to a roof that is sloped. Also, future coatings will be difficult because silicone is so slippery.
Although we apply both, customers tend to prefer acrylic roof coatings because they will be more easily recoated in the future and aren’t as slippery. Their primary downside is they will have to be cleaned periodically because they adhere more readily to dirt, which causes a loss of reflectivity.