Kynar 500 / Hylar 5000 PVDF and silicone-modified polyester (SMP) are both baked onto the coil at the coating line, and on install day you cannot tell them apart by eye. What you are choosing is what the roof looks like after eight or ten North Texas summers.
Both are coil coatings. Neither is sprayed on a panel.
The strip is cleaned, pretreated, primed, topcoated on the weather side, and baked at a peak metal temperature in the 400s Fahrenheit.
Film build is about the same for both systems: roughly 0.2 mil of primer and 0.8 mil of topcoat, a nominal 1.0 mil on the exposed face, with a thin wash coat on the back. Both survive the roll former and the brake without cracking.
What PVDF is
Kynar 500 is Arkema's trade name for polyvinylidene fluoride resin. Hylar 5000 is the same resin from Syensqo (formerly Solvay). Neither company makes paint; licensed paint makers buy the resin and formulate finishes like Sherwin-Williams Fluropon, PPG Duranar and AkzoNobel Trinar, and the coil coater applies them. The architectural grade you want on a roof is 70 percent PVDF resin blended with acrylic, and the coil tag or warranty should say so.
The carbon-fluorine bond in PVDF barely reacts to ultraviolet light, so the resin does not break down at the surface. PVDF paints also lean on inorganic ceramic pigments, which are UV-stable on their own.
The trade-off is a softer film that scratches and mars more easily in handling, and touch-up paint is an air-dry product that never quite matches a baked finish.
What SMP is
SMP is a polyester resin with silicone added to slow UV breakdown. Common lines are AkzoNobel Ceram-A-Star and Sherwin-Williams WeatherXL. It is harder than PVDF, more scratch-resistant, usually glossier, and cheaper.
Polyester absorbs UV. Over years of sun the binder at the surface degrades and leaves loose pigment and titanium dioxide sitting on top. That white powder is chalk. Drag a finger across an old SMP roof and it comes off like talc. Fade is the separate problem. Premium SMP lines use ceramic pigments in standard colors too, but brights in any system lean on organic pigments, and in SMP they lose color under the same UV that chews the resin.
Why it shows up in year eight
UV dose is cumulative, and in this climate the damage shows first on south- and west-facing slopes, in dark or bright colors. On SMP that usually means visible chalk or a shifted color somewhere in the back half of the first decade. A PVDF roof from the same year still reads as the color it was ordered in.
Where you notice it is the day a hail claim or an addition puts a fresh panel next to an old one, and the new material is two shades darker.
| PVDF (Kynar 500 / Hylar 5000) | SMP | |
|---|---|---|
| Resin | 70% fluoropolymer, acrylic blend | Silicone-modified polyester |
| Pigments | Inorganic ceramic; some brights organic | Ceramic in standard colors; organic in brights |
| Fade and chalk | Slow | Faster, color-dependent |
| Scratch and mar resistance | Lower, softer film | Higher, harder film |
| Gloss | Low to medium | Medium to high |
| Cost | Premium | Lower |
| Typical use | Residential, architectural, long-life roofs | Agricultural, commercial, light colors |
Reading the finish warranty
A paint warranty is three separate promises, and the numbers matter more than the headline years.
- Film integrity: the paint will not peel, crack or check. Both carry this; SMP film integrity is often written at 40 years or lifetime, which is where a bigger headline number usually comes from.
- Chalk: measured to ASTM D4214 Method A, where 10 is no chalk. PVDF warranties are commonly written at a rating of 8 or better for 30 years. SMP warranties typically hold 8 only on sidewalls and allow 6 on roof slopes.
- Fade: measured to ASTM D2244 in Hunter Delta E units. PVDF warranties are commonly written at 5 Delta E or less. SMP warranties typically allow 7 Delta E on roofs and 5 on walls.
Years of coverage vary by coater and by color, so read the actual document, not the brochure. Watch for shorter terms on bright colors and metallics even within PVDF, slope minimums, and registration requirements. The paint warranty is also separate from the substrate warranty on the Galvalume or galvanized steel underneath. And those thresholds are limits, not a promise the roof still looks good next to new material.
Which colors need PVDF
- Bright reds, blues, greens, oranges: PVDF. These are the organic-pigment colors that fade fastest in SMP.
- Dark colors (black, charcoal, dark bronze, dark brown): PVDF. Dark panels run hotter, heat speeds up resin breakdown, and white chalk on a black roof is impossible to miss.
- Metallics (copper penny, silver, champagne): PVDF in practice. Mica and aluminum-flake pigments are offered in PVDF lines. Metallic coil also has directionality, so order panels and trim from one coil lot.
- Whites, light grays, tans, light stone: SMP is a reasonable spec: inorganic pigments, low heat gain, and chalk on white is nearly invisible.
The cost difference
PVDF coil costs more per square foot than SMP in the same gauge and color; the gap moves with the steel market and color, so get a current quote. On an installed standing seam roof, paint is a small slice next to labor, clips, underlayment and the panel itself. Chalk and fade are cosmetic and a chalked SMP roof still sheds water; the expensive version is a repaint, or a roof torn off for looks with sound steel underneath.
Frequently asked
What is the difference between Kynar 500 and Hylar 5000?
Both are trade names for PVDF (polyvinylidene fluoride) resin, Kynar 500 from Arkema and Hylar 5000 from Syensqo (formerly Solvay). Licensed paint makers blend either one into 70 percent PVDF architectural finishes, so they perform the same on a roof.
Which metal roof colors need a PVDF finish instead of SMP?
Bright reds, blues, greens and oranges, dark colors like black and dark bronze, and all metallics should be PVDF because they fade or chalk visibly in SMP. Whites, light grays and tans hold up well enough in SMP for agricultural and commercial work.
What does a metal roof paint warranty actually cover?
Three separate things: film integrity (no peeling, cracking or checking), chalk measured to ASTM D4214 Method A, and fade measured to ASTM D2244 in Hunter Delta E units. PVDF warranties are commonly written at a chalk rating of 8 and 5 Delta E for 30 years; SMP warranties typically allow a chalk rating of 6 and 7 Delta E on roof slopes, and the years of coverage vary by coater and color.