When it’s time to pick out a color for your new metal roof, the decision gets slightly more complicated when you also have to choose which kind of paint system, or coating system, you want. While the type of paint might not seem important, it does play a big factor in the longevity of your roof’s appearance.
The two most popular coating systems for metal panels are SMP (Silicone Modified Polyester) and PVDF.
Some colors are offered in both systems, so what’s the difference? You may be tempted to choose SMP just because it is the more affordable option. However, the paint system has some downfalls that might not be worth the cost savings.
At Western States Metal Roofing, we manufacture panels in both SMP and PVDF paint systems. We have compared both systems and believe both are excellent products. However, PVDF is a more premium product of superior quality when compared to SMP. This doesn’t mean you should rule out SMP panels, as these panels also provide a great amount of value.
We want to make sure you are aware of any potential shortcomings associated with SMP paint before you make a buying decision.
Here are the three most common problems with SMP paint.
Fading refers to the roof’s visible loss of color over time. It results directly from the chemical breakdown of a coating’s base resins and pigments. The breakdown happens from factors such as chemicals in the atmosphere, moisture, pollution, and UV rays.
The silicone in the SMP paint helps protect the color from fading. For this reason SMP paint performs better than less expensive polyester paints without any silicone in them. However, the structure of SMP is not strong enough to prevent fading from happening eventually.
The result of fading usually is a much lighter, dull color. However, some colors might turn into a completely different color. The color of the roof might even appear to be uneven.
It’s very possible to have different levels of fading throughout a roof if one side receives greater exposure to the sun. If you choose a red roof, the side that's often in the shade could remain vibrant, while the other side of the roof that’s exposed to the sun could appear dull and old.
While fading does not affect a roof’s performance, it does greatly impact a roof’s appearance. While fading will eventually occur with any type of paint system, SMP painted panels will fade faster than a more expensive option like a PVDF paint system. The fading will be less noticeable with a neutral color such as white, tan, or light stone. If you have a bright and vibrant color, PVDF would be a better option.
The length of time it takes fading to occur will always vary. However, there are certain climates that will expedite the process.
Since UV rays cause fading, any area where the sun is shining strong on a regular basis is going to cause SMP roofs to fade faster. For this reason, a black roof in Maine would likely fade slower than a black roof in Florida.
A roof that is close to a coastline will fade faster due to the salt in the atmosphere. Actually, any kind of constant contact with moisture will have an effect on the roof’s pigment. Exposure to moisture such as saltwater, condensation, snow, or rain will cause fading over time.
An area that experiences extreme temperatures, whether tropical heat or polar vortex type conditions, will cause accelerated fading. The chemical makeup of the paint is also weakened if there are frequent fluctuations in temperature.
This is when the appearance of a powdery substance forms on the surface of a coating. If you touched the roof’s surface, you would have a white, chalky residue on your fingers. Chalking occurs faster on SMP panels than it does on PVDF painted panels.
Similar to fading, chalking is caused by the breakdown of resins. It’s an undesirable appearance that keeps the roof from looking fresh and new.
While not as many environmental factors contribute to the white residue when compared to fading, climate does take a role in the speed chalking occurs. UV rays from the sun will expedite the chalking process, so areas that are usually sunny will generally see chalking occur more rapidly.
Lighter colored panels, such as certain gray colored metal roofing, make the appearance of chalking less apparent as the chalky substance blends in with the color. The lighter the color, the less noticeable the white residue will be. While it’s not a solution that will prevent chalking from happening, it might make the undesirable powdery appearance less noticeable.
If you are planning on having a dark-colored roof, you may want to avoid using SMP panels. The dark panels will only make the chalking more apparent. For example, chalking will be more noticeable on an Emerald Green roof and less noticeable on a Polar White roof.
Western States Metal Roofing Panel Colors Available In SMP Paint
The third problem with SMP panels is the limited choices in terms of color. There is a much wider availability of colors that come in PVDF paint instead of SMP.
This might not be an issue if you are looking for a basic color. However, specialty colors like metallic or panels that look weathered are going to be done with PVDF coating systems.
For tips on choosing a metal roof color we recommend this article:
Metal Roofing Colors: 5 Tips To Pick The Best Metal Roofing Color
SMP is made of polyester and silicone intermediates. Silicone acts to improve the gloss retention and weather resistance of the coatings. The higher the silicone content, the better the performance of the paint.
The amount of silicone in the coating varies depending on the manufacturer. This means that not all SMP paints are created equal. Some SMP systems are of better quality than others.
SMP paint is considered to be “middle of the road” when it comes to roofing paint systems. They are better than polyester paints that do not have the protective silicone, but not nearly as high quality as PVDF.
At Western States Metal Roofing, we offer metal panels in both SMP and PVDF paint systems.
If you have decided that SMP is not the right paint system for your roof, we have a wide selection of PVDF colors to choose from. Start by taking a look at our available colors in both paint systems to decide which colors you are interested in for your project.
If you would like to learn more about the differences between a PVDF and SMP paint system, we recommend that you read:
Best Paint For My Metal Roof Panels: SMP Paint v PVDF