Kynar (PVDF) vs. SMP vs. Polyester Paint on Metal Roofing Coil

Short answer: a 70% PVDF finish, made with Kynar 500 or Hylar 5000 resin, holds color longest and chalks least. It meets AAMA 2605, the highest AAMA standard for sunlight. SMP costs less and does well on most inland roofs. Straight polyester is a budget finish for trim, soffit and outbuildings, not for a long-warranty roof.

What each paint system is

All three are factory-applied coil coatings. The coater cleans and pretreats the metal, rolls on a primer and a color coat, then bakes the finish. Sherwin-Williams lists the same 0.9 to 1.1 mil topside film for its Fluropon PVDF and WeatherXL SMP systems. The difference is the resin.

• 70% PVDF. The resin is polyvinylidene fluoride, a fluoropolymer. Arkema sells it as Kynar 500 and has supplied it for architectural coatings since 1965. Coaters blend it to 70% of the resin. Examples are Sherwin-Williams Fluropon and AkzoNobel Trinar.
• SMP (silicone-modified polyester). A polyester with silicone added for weathering and gloss retention. Examples are Sherwin-Williams WeatherXL and AkzoNobel Ceram-A-Star 1050.
• Polyester. A general-purpose resin. Sherwin-Williams lists its PolyPREMIER polyesters for trim coil, soffits, rainware, storage buildings and residential siding.

Metallic colors and handling

Metallic colors change the build. Sherwin-Williams’ Fluropon Classic uses aluminum-based pigment under a clear coat. That makes it a three-coat system with 1.3 to 1.7 mils on top. Its Classic II gets a metallic look from mica in two coats. Ask which system a metallic color uses, because warranty terms can differ.

Handling matters too. AkzoNobel says its Ceram-A-Star 1050 SMP resists scratching and abrasion better than PVDF in transit and on the roof. It points to hot weather, when handling marks are more likely. On PVDF jobs, protect stacked panels and keep foot traffic on the flats to a minimum.

How chalk and fade are measured

Fade is color change. It is measured under ASTM D2244 and reported in Hunter ΔE units. Most PVDF data uses 5 ΔE as the limit.

Chalk is the powdery residue weathered paint leaves on a cloth. ASTM D4214 gives it a number rating, and a higher number means less chalk. PVDF data and warranties usually hold to #8.

Coaters prove their claims on South Florida test fences, with panels tilted 45 degrees to the south. AkzoNobel says one year there equals about two years in most of North America.

Performance side by side

	70% PVDF	SMP	Polyester
Example systems	Fluropon, Trinar	WeatherXL, Ceram-A-Star 1050	PolyPREMIER
AAMA spec listed	AAMA 2605	AAMA 2604 (WeatherXL)	AAMA 2603
Florida color result	5 ΔE or less at 20 years	WeatherXL: 5 ΔE vertical, 6 ΔE sloped at 20 years	Not listed on the data sheet
Florida chalk result	#8 or better at 20 years	WeatherXL: #8 vertical, #7 sloped at 20 years	Not listed on the data sheet
Relative cost (Sherwin-Williams guide)	$$$	$$	$

The AAMA numbers explain the gap. AAMA 2605 requires ten years of South Florida exposure. The coating must stay within 5 ΔE, keep a chalk rating of 8 or better and hold 50% of its gloss. AAMA 2604 is a five-year test with 30% gloss retention. AAMA 2603 is a modest standard by comparison.

What finish warranties usually promise

A finish warranty makes three separate promises. Film integrity means the paint will not peel, crack or flake. Chalk and fade are shorter promises with number limits. These published figures show the usual range.

Promise	70% PVDF	SMP	Polyester
Film integrity	35 to 40 years	40 years	Generally 20 years or less
Chalk	#8 for 30 to 35 years	#8 on walls, #6 on roofs, 30 years	Color coverage generally 10 years or less
Fade	5 ΔE for 30 to 35 years	5 ΔE on walls, 7 ΔE on roofs, 30 years	Color coverage generally 10 years or less

Sherwin-Williams gives Fluropon Continuum a 35-year chalk and fade warranty on coil. It says that is five years longer than existing warranties for two-coat mica PVDF systems.

Look closely at the roof column. Roofs get more sun than walls, so SMP terms loosen on roofs. Some colors get shorter terms too. One sample PVDF warranty drops matte black to #6 chalk and 9 ΔE for 20 years. It gives metallic colors no fade rating at all.

Cost order

Sherwin-Williams ranks its own lines by cost. Polyester is lowest, SMP is in the middle and 70% PVDF costs more. AkzoNobel markets Ceram-A-Star 1050 as a lower-cost alternative to PVDF. For real numbers, send the gauge, width, finish and color with your quote request.

Which finish fits a New Jersey job

Shore and bay-front roofs

Here, distance to salt water matters more than the paint. One sample PVDF warranty gives no coverage within 1,500 feet of a coastline or of salt or brackish water. One coastal finish warranty covers aluminum and requires a fresh-water rinse at least twice a year. Sherwin-Williams lists its Flurothane PVDF system for coastal sites. Read aluminum vs. steel roofing near the coast before you order.

Commercial and public work

When the spec names AAMA 2605, you need a coating that meets it, such as a 70% PVDF system like Fluropon or Trinar. PPG notes that FEVE resin systems can also qualify. The WeatherXL SMP data sheet cites AAMA 2604. Sherwin-Williams lists Fluropon for commercial and monumental buildings.

Houses, barns and garages

SMP fits most inland residential and farm roofs. Sherwin-Williams lists WeatherXL for residential, agricultural and commercial roofing and wall panels. Choose PVDF when the owner wants color to hold for decades.

Trim, soffit and rainware

Polyester is common here, and PolyPREMIER lists trim coil, soffits and rainware among its uses. On a roof, bend the trim from the same finish as the panels so color and gloss match. Keep touch-up paint such as Sherwin-Williams Ready Match to small scratches. One coastal warranty excludes areas where touch-up paint is applied.

How to read a finish warranty

1. Find the issuer. A coil processor may issue it, but coating questions often go back to the paint maker.
2. Read three clocks. Film, chalk and fade each have their own term and limit.
3. Check roof and wall limits and your color. Matte and metallic colors can have exceptions.
4. Read the exclusions. Look for salt-water distance, copper or lead runoff, substrate or cut-edge corrosion and snow guard or solar attachment areas.
5. Note the paperwork. One sample requires a written claim within 30 days, the coil or skid tag number and panels formed within six months of shipment.
6. Check the remedy. It is usually refinishing, replacement material or a refund capped at the material price, not labor.

Keep the tag from every coil on the job. Then register the finish with the warranty registration form and read our warranty summaries.

Quick answers

Is Kynar 500 the same thing as PVDF?

Kynar 500 is Arkema’s brand of PVDF resin. Hylar 5000 is another PVDF resin named in coil warranties. Either way, the finish blends the PVDF to 70% of the resin.

Will an SMP roof chalk?

Some, over time. AkzoNobel’s Ceram-A-Star 1050 field performance allows a #6 chalk rating on roofs but #8 on walls, over 30 years.

Can I touch up scratches?

Yes, on small scratches. Keep it small, because one coastal warranty excludes touched-up areas.

Sources

Figures in this guide come from the documents below or are calculated from them. Specs and warranty terms change, so check the current version before you order.

1. Sherwin-Williams, Fluropon 70% PVDF Coil Coating Systems (product data sheet)
2. Sherwin-Williams, WeatherXL Silicone Modified Polyester Coil Coating System (product data sheet)
3. Sherwin-Williams, PolyPREMIER Coil Coating Systems (product data sheet)
4. Sherwin-Williams Coil Coatings, Coil Coating Comparison Guide
5. Sherwin-Williams, Fluropon Continuum announcement (April 13, 2021)
6. AkzoNobel, The Qualities of TRINAR LG/LS (PVDF product information)
7. AkzoNobel, The Qualities of CERAM-A-STAR 1050 (SMP product information)
8. AkzoNobel, CERAM-A-STAR 1050 Proven to Perform
9. Sheffield Metals, 40-Year PVDF (Kynar 500 / Hylar 5000) Paint Warranty, sample
10. Sheffield Metals, 40-Year Coastal Paint Warranty for Aluminum, sample
11. Sheffield Metals, Metal Roofing Paint Warranties
12. PPG, FGIA/AAMA 2605
13. Products Finishing, Understanding AAMA Specifications
14. Arkema, Kynar 500 PVDF resin for architectural coatings