Silicone Vs. Acrylic Roof Coating: A Comprehensive Comparison

As a building owner or contractor, elastomeric roof coatings are your go-to option if you want to save money and build a long-lasting structure for your immobile or mobile home roof seal. There are four common types of elastomeric roof coatings, of which silicone and acrylic roof coatings are the two most popular ones. 

Their popularity stems from the fact that they are environmentally friendly, cost-effective, and durable. But before we compare acrylic vs silicone roof coating, we will first look at some background information about them. 

The goal of this comparison is to help you make a better choice between silicone roof coating vs. acrylic roof coating should you be undecided about which roof coating technology to use. Read on to learn more!

What Is Silicone Roof Coating?

Silicone roof coatings are made from silica and other chemical formulas or additives, which give them their appearance, qualities, and benefits. They are basically applied on roof surfaces such as metal, membranous substrates, concrete, aluminum, asphalt, polyvinyl chloride (PVC), spray polyurethane foam (SPF), etc.

We also want to point out that silicone roof coatings are becoming more popular than acrylic ones. In fact, their market size could reach $231.8 million with a CAGR of 4.1% between 2022 and 2027. The reason for this growth rate is their increasing demand in the industrial and residential building sectors due to silicone’s sustainability and enhanced benefits over acrylic roof coatings.

Benefits of Silicone Roof Coating 

Contractors or commercial building owners choose silicone roof coating because of the following reasons:

  • They resist ponding: After curing, water does not affect silicone roof coatings. As a matter of fact, they are only affected by chemicals that probably may not occur naturally. As a result, they do not pond or deteriorate due to the actions of water.
  • They do not crack from exposure to heat: Silicones have high tensile and elongation strength that keep them from breaking when exposed to extreme temperatures and pressures. In fact, chemically, with all things being constant, there is almost no reaction when silicone comes in contact with heat or steam.
  • They reflect energy and sunlight: UV radiation does not affect silicone as much as it affects acrylic roof coatings. As a matter of fact, they have high emissivity, i.e., they emit and reflect thermal and UV radiation.
  • They are environmentally friendly: Silicone roof coatings are not very reactive and apparently do not cause environmental concerns. The only downside is their bad smells that disappear after curing.

Consideration of silicone roof coating

Though silicone would always win in a general silicone vs. acrylic roof coating comparison, this doesn’t mean silicone roof coatings are without downsides. Some considerations of silicone roof coatings include:

  • They accumulate dirt: Silicone roof coatings are not sacrificial, meaning that they do not wash away from water actions, and they do not absorb the water either. This can cause dirt or impairments to accumulate on silicone-coated roofs. Therefore, you’ll need to maintain your roof occasionally to avoid this. Ultimately, this adds to the cost of silicone roof coatings.
  • Another consideration is that silicone is slippery when wet. Silicone-coated roof surfaces that are regularly treaded would require the installation of special pedestrian paths. This is because silicone-coated surfaces are slippery when wet and could cause accidents for unknowing walkers.
  • Unpleasant smell during application or installation.
  • Not recommended for sloping roof surfaces: Silicone roof coatings are best suited for flat roofs because of their non-sacrificial and slippery nature when they come in contact with water.

What is Acrylic Roof Coating?

Acrylic roof coating is a water-based roof coating made from acrylic resin and other additives that give it a standout quality. Acrylic roof coatings are often attributed to being the original elastomeric roof coating, which inspired the new age of elastomeric coatings.

Today, they are preferably used in sloped roofs because they are sacrificial and can wash away with the activity of weather or any extreme environmental or atmospheric conditions. These contribute to why building owners and contractors increasingly consider other roof coating alternatives like butyl, silicone, epoxy, etc.

Acrylic Roof Coatings Pros and Cons

Starting with the pros of acrylic roof coatings, we have:

  • Aesthetically appealing: Acrylic roof coatings are reflective and sacrificial, which helps them maintain their visual appeal over time. 
  • Cost-effectiveness: Acrylic roof coating is cheaper. Although its use is increasingly rivaled with other roof coating options, they are still the go-to option if you are on a budget.
  • Impressively dirt-resistant: The sacrificial or chalky nature of acrylic roof coatings makes them dirt-resistant. This also makes them visually appealing because they maintain their colors and quality that way.
  • Easy to install or apply: Acrylic roof coatings are water-soluble and easy to use. They are also cheaper than silicone roof coating. And you can apply them yourself by following a few DIY instructions.
  • Finally, acrylic roof coatings are a good alternative to other types of elastomeric roof coating for sloped roofs. In that case, they are UV resistant to an ample extent, waterproof, durable, and easy to maintain. As a result, they are best suited for residential buildings, which primarily have sloped roofing systems.

Now, let’s see some considerations of acrylic roof coating before we proceed to learn about how it is different from or compares with silicone roof coating:

  • Breaks down or ponds under harsh conditions: Acrylic roof coating is super reactive to environmental changes, forcing it to break down or wear over time as it encounters more challenges.
  • They are unreliable for commercial uses: Their ability to wear or lose their mil thickness in extreme weather or UV conditions could cause commercial building roofs to leak over time. This makes acrylic roof coating unreliable for commercial or large-scale purposes.
  • Poor thermal conductors and reflectors: Due to the brittle texture, acrylic roof coatings tend to absorb impurities, heat, and UV radiations, interfering with their chemical components and causing them to lose value over time.

That said, let us now see how both acrylic elastomeric vs. silicone roof coatings compare. The following detailed comparison lets you decide which would work best for your next roof coating project.

Major Differences Between Silicone Roof Coating and Acrylic Roof Coating

In this section, you’ll learn about the core differences between acrylic roof coating and silicone, which could influence your decision-making process. Therefore, we advise you to read carefully.

Silicone Vs. Acrylic Roof Coating: Difference in Durability and Warranty

On average, elastomeric roof coatings last between 10 to 50 years. However, while silicone coatings could last up to 50 years and above, acrylic roof coatings tend to last for less than 20 years.

It’s no surprise why many roof coating producers confidently put warranty options on their silicone roof coating products. However, this warranty still depends on other factors like additives used during the production process and the thickness of the roof coating.

Several factors make silicone roof coatings last longer than acrylic. One is silicone’s exceptional durability—its ability to withstand extreme pressure or wear and tear. Silicone roof coating is not sacrificial like acrylic and does not chalk. 

The sacrificial or brittle nature of acrylic roof coating makes it wear off as it comes in contact with rainfall and UV radiation. Unlike silicone roof coatings that possess the desiccant properties of silicone, keeping it consistent at all times.

Secondly is their tensile and elongation strength. While both elastomeric roof coatings may have similar tensile strength, their elongation strengths differ. Silicone membranes are very elastic and can weather extreme pressures, unlike acrylic roofing, which may break or wear off at certain high temperatures or pressures. This makes silicone roof coating more durable than acrylic.

Silicone Vs. Acrylic Roof Coating: Difference in Cost

If you are on a budget, then acrylic roof coating may be your best option. Remember, we mentioned earlier that silicone roof coatings, especially the grey elastomeric roof coating, may occasionally require janitorial maintenance to avoid dirt accumulation over time. You may prevent such costs with acrylic roof coatings, which wear off the dirt or dust as wind or rainfall acts on it.

Also, when it’s time to replace a silicone-coated roof, you’ll pay more than it would normally cost to replace an acrylic-coated roof. This is because the installation or application team would have to remove the entire silicone membranous coating to put in a new one. On the other hand, acrylic could easily wash off with chemical or liquid pressure or action.

Another way to look at the elastomeric roof coating price of acrylic roof coating vs silicone is their market and production costs. Apparently, the cost of production and supply chain factors of both elastomeric roof coatings will ultimately affect their market prices. In that case, silicone vs acrylic roof coating materials and distribution funnel affect their cost difference.

With that in mind, let’s compare the prices per square meter of silicone roof coating vs acrylic. If you overlook labor costs, installing a single coat of 20 mil silicone roof coating would cost an average of US$1.55 and US$2.02 per sq ft. To add another coating layer could cost an extra US$0.30 to US$0.50 per sq ft.

On the other hand, an acrylic roof sealer’s average cost would be anywhere from US$0.30 to US$0.90 per sq ft. Seeing the difference in installation prices should tell you which is cheaper and which is more costly. Nevertheless, your decision should not be based on cost alone. Try looking at the bigger picture, which may include durability, thermal reflectivity, and the nature of your roof or building.

Silicone Vs. Acrylic Roof Coating: Difference in Thermal Conductivity, Reflectivity, and Emissivity

One of the reasons why we coat our roofs is for their thermal conductivity, reflectivity, and emissivity benefits. In fact, it’s one of the things to keep in mind when planning your roof coating. 

Conductivity refers to their ability to transfer heat across material depth and length. On the other hand, reflectivity refers to how well the product can bounce UV radiation across a given length. Meanwhile, emissivity refers to how much heat they can let off over a given period and length of coating material.

Typically, a coated roof reflects about 88% of the UV radiation that comes in contact with it. Meanwhile, a non-coated roof absorbs 83% of these rays instead of reflecting them. This should give you a hint about the importance of the thermal conductivity and reflectivity of silicone vs acrylic roof coatings.

Silicone roof coating has low thermal conductivity. This explains why it remains stable even with temperatures above 250 degrees Celsius. As a result, silicone roof coating transfers heat more slowly than acrylic ones. Their excellent heat resistance is why they can maintain their structures and properties even after they come in contact with high thermal ranges, unlike acrylic roof coatings, which could break with high thermal action.

In terms of reflectivity, silicone and acrylic are almost similar. The reason, however, depends on the color of the elastomeric roof patch. Typically, we could have silicone in custom colors or white, tan, light gray, and dark gray elastomeric roof coating. The same applies to acrylic.

In the end, reflectivity depends on the user, the building, or the purpose of the coating. Usually, white or grey elastomeric roof coatings reflect about 80-90% of UV radiation and reduce heat flow into your building through the roof. Now, choosing to use a darker-colored elastomeric roof coating means that you understand thermal reflectivity and emissivity theory.

Silicone Vs. Acrylic Roof Coating: Difference in Elongation and Tensile Strength

Earlier, we mentioned excellent elongation and tensile strength among the benefits of silicone and acrylic roof coatings. Now, the question is, which of them has a greater tensile strength over the other? In this section, we’ll elaborate on that. 

When we talk about elongation and tensile strength in elastomeric roof coatings, we mean how much such a coating could stretch or resist tearing under tension. Typically, your building or building structures would regularly experience expansion or reduction in size or volume as you experience different weathers, pressures, and temperatures. 

Worse case, if the coating used in your roof has low tensile strength and elongation percentage, it could cause roof leaks or breakdown over time. So, you see why it’s important to also consider the elastomeric roof coating’s elongation percentage and tensile strength before finalizing your decision.

In an acrylic vs silicone RV roof coating elongation comparison, silicone comes out on top. Although both have impressive tensile strengths, a silicone roof coating can better resist tear and gravitational pressures per sq inch than acrylic. Acrylic roof coating can tear at a lesser elastic limit than silicone roof coatings.

Nevertheless, they are both good if you use a good product or apply them correctly and for the right purposes. So, ensure you check the labels for the product you’re about to use. Usually, the roof coating products, be it silicone or acrylic, would have labels of their elongation strength in percentages. 

A good roof coating should have at least 200% elongation at 70 degrees Fahrenheit and above. And at least 250 psi or 20lbf/in for their tensile strength.

Silicone Vs. Acrylic Roof Coating: Difference in Installation or Application

Well, this is where acrylic roof coating wins. As a water-soluble chemical, acrylic roof coatings can be easily applied to roof surfaces without any hassles. It doesn’t matter if you apply it as a spray roof coating or roll-on roof sealant—you could do it as a DIY activity with little or no expertise in the field.

However, this is different for silicone roof coatings, which can be hard to apply and require certain techniques to maintain the mil thickness and avoid wastage due to their high costs. 

Additionally, equipment used to install or apply silicone roof coatings can take a lot of work to clean. Since they are not water-soluble, you’ll need ultra-solvents like virgin mineral spirits or chemicals to rinse them.

Now is also a good time to discuss the foul smell released when applying silicone roof coatings. As a safety precaution, use a mask to avoid inhaling unhealthy chemicals during silicone roof coating application.

Also, ensure you buy products that are environmentally certified by a government or non-governmental organization to avoid inhaling chemicals of unknown origins during application. A good way to find such products is by reading online silicone roof coatings reviews or comparison guides like this one or buying recommended products from certified sources like us at LengendDay.

Silicone Vs. Acrylic Roof Coating: Difference in Maintenance

We’ve mentioned that maintaining silicone roof coating can cost more than acrylic. However, it would depend on the type of maintenance you intend to perform—sealing or entire roofing. It would also depend on the roof size and the thickness of the product used before the maintenance.

Acrylic roof coating should not give you any technical problems during maintenance. The reason is that by the time you might want to maintain or replace them, they would have been damaged or worn in a way that allows you to easily scrape them off or sweep them away.

For silicone, the situation is quite different. Most times, maintenance may be about something other than replacing the silicone roof coating. It could be just janitorial maintenance or roof sealant sort of maintenance. 

A roof sealant maintenance is the maintenance you do to repair leaking areas on a silicone-coated roof. A case study would be when there is hail damage on the roof. Apparently, this could affect the substrate and TPO of the roof and cause leakage on the siliconized acrylic or whatever roof coating you’ve used. 

So when the abovementioned situation happens, you do not have to replace the entire roof coating—only the severely affected areas. This would save you costs in the long run. 

Meanwhile, maintenance can be complex if it’s about removing the entire silicone roof coating membrane. First, you’d have to remove the membranous layer—many installation teams prefer to remove the substrate and install an entirely new one. So it becomes easier to apply a new silicone roof coating. 

Silicone Vs. Acrylic Roof Coating: Difference in Aesthetics 

At first, silicone roof coating is visually more appealing than acrylic. But after a while, acrylic wins in aesthetics. Acrylic is dirt-resistant as it washes off dirt by sacrificing part of its quality in the long run. That way, it maintains its aesthetics. Although, after a while, this becomes an issue that leads to wear and tear. 

Meanwhile, silicone accumulates this dirt because it is desiccant and ensures that the water around it dries alongside the dirt in it. At the end of the day, the dirt accumulates, making silicone roof coatings appear cloudy or dusty, hence less appealing.

Before the action of dust on silicone roof coating, its appearance is shiny, smoother, and better-looking than acrylic. Silicone looks like an epoxy coating, which is polished and even more appealing in sunlight. But acrylic is brittle and chalky.

Note that aesthetics shouldn’t be the only reason to choose to use silicone or acrylic roof coating. In this case, it should be a side note in plans. But only if you think it’s worth noting. The choice is yours.

Silicone Vs. Acrylic Roof Coating: Difference in Curing Time

Curing time is the period it takes an elastomeric roof coating to dry up, harden, or become most effective. This criterion is important because it helps you to know when it’s best to apply any of the aforesaid clear elastomeric roof coatings.

For silicone roof coating, curing time is anywhere between 1 to 4 hours under normal atmospheric conditions. The curing time varies with the application method, the thickness of the silicone roof coating, the weather of the application, or the product used—additives may affect the curing time.

For acrylic roof coating, complete curing time could take up to 1 week. Like the conditions listed for silicone application, the same applies to acrylic roof coatings. However, while curing may not be complete as needed, acrylic roof coating may still be effective enough to present some of its core benefits to the user.

Also, note that applying acrylic elastomeric vs silicone roof coatings in cold winter will give you a faster result for both. This is because, during winter, everything tends to harden faster. However, making up your mind using this criterion, ensure you have also considered other factors in this comparison and the type of acrylic or silicone product to use.

Silicone Vs. Acrylic Roof Coating: Difference in UV Stability

UV stability is a measure of how much a clear elastomeric roof coating may resist the effect of UV rays caused by sunlight. UV radiation constantly troubles the chemical properties of the elastomeric roof coatings, affecting their quality and making them suffer damages from its action.

That said, silicone roof coatings are more stable over UV radiation than acrylic. The reason is simple: silicone reflects sunlight better than acrylic due to its shiny epoxy nature. This reflectivity property we discussed earlier is why silicone can resist the sun’s harsh UV radiation.

Another reason is silicone’s strong covalent bonding that allows them to be tightly held together so that UV radiation does not pass through easily. We cannot say the same for acrylic roof coating. Because at the end of the day, many of the reported damages on acrylic roof coatings result from UV radiation.

Silicone Vs. Acrylic Roof Coating: Difference in Permeability and Resistance to Ponding

Silicone roof coating is waterproof and desiccant, meaning it does not allow water to pass through it. This is also a major reason silicone is in high demand and suited for buildings with flat surfaces—since water cannot permeate or collect around it for a long time.

On the other hand, acrylic roof coating is water-solvent and absorbs water to a degree, which becomes visible after a long period. This absorbent or reactive nature of acrylic roof coating to water makes it less resistant to ponding.

If you truly want to worry less about ponding and energy conservation in your building, consider silicone roof coating. By now, you must also know silicone roof coating’s pros and cons. This should tell you other factors to look into aside from permeability and resistance to ponding when finalizing your choice.

Silicone Vs. Acrylic Roof Coating: Difference in Environmental Friendliness

After all is said and done, we must also consider our environment and health safety when choosing the elastomeric roof coating technology to use. Environmental friendliness or sustainability is one of the reasons why silicone and acrylic roof coatings are widely used today over other elastomeric or alternative roof coatings.

While many sources may argue that silicone roof coating is more environmentally friendly than acrylic, it is essential to point out that both are equally environmentally friendly. This argument is based on the fact that silicone roof coating was improved as inspired by the limitations of acrylic to include very low counts of volatile organic compounds.

But on the flip side, the water-based nature of acrylics also makes them safe for the environment. Eventually, environmental friendliness will come down to the manufacturer of the elastomeric roof coatings. To enhance their product, producers may include additives that could cause respiratory conditions, chemical exposures, etc.

As a rule of thumb, ensure that the product you use is certified by an organization before using it. That way, you don’t end up buying a product that keeps you and your environment in a bad state in the long run.

Conclusion

Elastomeric roof coating technology gives us the comfort and relaxation needed for our roofs. Not only does it offer these benefits, but it also helps us to cut costs and conserve energy or heat.

If you’re still wondering, what is the best elastomeric roof coating? Then, you have a detailed answer based on reports from this comparison. From this comparison, it’s obvious that silicone tops the chart for the best elastomeric roof coating option to consider. 

Meanwhile, if you need further guidance on using silicone roof coating technology, you can reach out to us or see our blog or resource center for beneficial guides and comparisons.

We at LegendDay manufacture different silicone products, including silicone roof coatings. You may check out our main page or product catalog for other sustainable silicone products you may want to try out today.

FAQ

1. What Is the Longest-Lasting Roof Coating?

The longest-lasting roof coating is probably silicone roof coatings. Silicone roof coating can offer a warranty of up to 50 years, depending on the additive or product used. The reason is that silicone roof coatings are durable and are very stable over sun or thermal radiation. Plus, they do not pond or wear off in quality due to water or chemical actions over time.

2. Is Silicone Good for a Flat Roof?

Yes. Flat roofs are usually prone to ponding and percolation. The reason is that water may reside on the roofs after heavy rain or hail falls. As a result, silicone roof coating’s desiccation properties make them a good option for flat rooftops. Aside from desiccation, silicone roof coating offers other benefits to flat roofs, like high UV reflectivity, thermal conservation, and better elongation and tensile strength.

3. Does Silicone Roof Coating Stop Leaks?

Yes, silicone roof coatings can stop leaks. They are membranous and act as fillers, especially when applied on rough roof surfaces or roofs with high porosity or prone to surface expansion due to thermal or chemical actions. Silicone can be used to treat such roofs if there are leaks.

4. What Is the Difference Between Roof Sealant and Roof Coating?

The primary difference between roof sealants and roof coating is that roof sealants are used to seal roof edges or specific or target areas on the roof to make them airtight and free from potential leaks. In contrast, roof coating is applied to the entire roof.

 

More resources:

Silicone vs Polycarbonate – Source: LEGENDAY

Is Silicone a Rubber, Elastomer, or Polymer? – Source: LEGENDAY

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