Tag Archives: Kynar

Kynar paint for Barndominiums

Kynar Paint for Barndominiums

Many potential barndominium owners are looking to get the greatest value for their investment and many see this as their ‘forever’ home. If you fall into this category, I would highly recommend exploring Kynar® painted steel.

I could extol aesthetic reasons to use Kynar painted steel for longer than anyone would be willing to listen.
Polyvinylidene fluoride is acknowledged as the premium resin for coil coatings. Popularly known by its original trade name Kynar, PVDF is a kind of fluoropolymer, a family which includes Teflon and Halar. Key to these chemicals’ toughness is the bond between carbon and fluoride, the strongest possible polymeric connection.

PVDF resin has superior chalk resistance and gloss retention, as well as stain and chemical resistance. It is softer than SMPs and polyesters, however, making it highly formable without risk of cracking, but also relatively easy to scratch during transport or installation. PVDF is most durable when it makes up 70 percent of resin; higher concentrations do not coat well, since acrylic is important for dispersion during coating processes.

There are two general classes of pigments. Organic, or carbon-based, pigments are generally synthetic and relatively inexpensive to make. However, organics have fairly weak molecular bonds which are easily broken down by moisture, UV and pollutants, and so, are prone to fading. Inorganic pigments are those which do not contain carbon, and may be naturally occurring or manufactured. They generally offer good fade resistance, with an exception of carbon black. Many simple inorganics are metal oxides, such as widely used iron oxide and titanium dioxide.

Kynar 500/Hylar 5000 systems, which are required to contain 70 percent PVDF, do not vary greatly between manufacturers. Since these paints carry 20- to 30- year warranties which allow for extremely little face, these companies all use ceramics and appropriate inorganic pigments.
One manufacturer we purchase Kynar 500 painted steel from is McElroy Metal. Here is a photo which really shows off performance differences between Kynar and SMP: http://www.mcelroymetal.com/elements/files/Kynar%20500%20VS.%20SP%20Flyer

Sadly, PVDF paints are not available nationwide. Personally – if available where I was planning to build and color choice was other than White, I would make an investment for better paint. I want my building to look as close to new as possible, for as long as I own it!

At NFBA’s (National Frame Building Association) 2019 Expo I cornered Sherwin-William’s representative for further information on Fluropon® (PVDF). Please enjoy this video:


Skylights Leaking

Skylights Leaking

Reader DIANA writes,  ”skylights leaking in 40 year old barn. Is it possible to replace the sky lights with metal.”

Skylights in steel roofs are problematic, and not just due to them eventually leaking. You will certainly want to read this article: https://www.hansenpolebuildings.com/2016/01/one-more-reason-to-not-use-skylights-in-steel-roofs/.

Now, considering your entire roof is 40 years old – it would be possible to replace only skylight panels. This would be providing rib configuration of steel can be matched. Over 40 years many patterns have been discontinued.

You asked for my expert opinion and I therefore take upon myself to answer as if it was my very own building. This isn’t about trying to make money (although some readers may become Hansen Pole Buildings’ clients following reading of a few of my articles), it is about people getting a great value for their building dollar. I’d be first to admit to it, if I did not believe our buildings are an example of best value.

If someone actually does happen to have a better value component, let me know and we will try to incorporate it and, if possible, improve upon it.

I’d look to replacing entire roof surface. Paint systems, such as Kynar (https://www.hansenpolebuildings.com/2014/05/kynar/), are available in most U.S. areas. There are also ‘Lifetime’ warrantees available on many SMP (https://www.hansenpolebuildings.com/2014/05/smp/) painted products.

Your existing roofing was probably installed using nails, rather than screws. It was industry standard then (read more here: https://www.hansenpolebuildings.com/2011/12/ring-shank-nails/). Ideally a new roof panel screw layout will be such as with some adjustment all existing nail holes can be missed.

I’d recommend using powder coated Diaphragm screws to attach roofing to underlying purlin framing. You can read why here: https://www.hansenpolebuildings.com/2012/08/this-is-a-test-steel-strength/.

The Importance of Paint!

Maximizing the Metal: Why Not all Metal is Created Part II
This article, by my friend Sharon Thatcher, was originally published in the September 2016 issue of Rural Builder magazine and appears unedited. To continue from last Friday:
While paint doesn’t provide any structural value, it certainly does add value to the end product. Unpainted panel still has a big audience, but painted coil is now more popular than ever and it’s what most customers see most clearly.
Dan Knight came up through the steel ranks via the paint industry and he explains the different types of paint.
There are three types of paint systems for metal that are commonly used here in the U.S.:
Polyesters: the least expensive, usually with a 10-year warranty on an exposed application.
“Polyesters are a very good workhorse but typically they don’t have the exterior durability that’s required on the warranted products,” Knight said. “So where you see them is on the low- or non-warranted systems such as interior liner panels, gutters, non-warranted or very low-warranted wall and roofing panels. There is always going to be a market need, some people call it shade-and-shelter. It’s located in the back 40 and it’s not expected to last 40 years.”
SMP (silicone polyesters): The most widely used, averaging a 40-year warranty on the film (but fade and chalk can occur over time).
“It’s basically a more durable exterior grade system. This is the workhorse in the rural builder’s market,” Knight explained. “This is commonly referred to as a 40-year paint system.”
PVDF (Polyvinylidene fluoride – trade names include Kynar and Hylar): the premium paint system, averaging a 25-year warranty, but with the best protection against fade and chalk.
“You see [PVDF] a lot in commercial buildings,” said Knight.
The thickness of the paint is important. The thicker the paint, the better the panel can weather the elements and protect the substrate.
For warranted material, the primer should be a minimum of .2 mils thick and the paint or topcoat at least .8 mils for a total of 1 mil thickness. Like steel, there is a range: for top primer the range is 0.2-0.3 mils; the top paint or coat is 0.7-0.8; and the bottom or backer with primer is 0.5-0.7 mils.
“This is where understanding the supply chain of the paint system is important,” Knight said. “What you have to understand is that the paint warranty only covers three facets:
Chalk: This is a degradation of the resin and the pigments over time. When you rub your hand on the coating, it leaves a white residue.
Fade: the depth of color difference, say when a dark brown paint turns to a light brown.
Film integrity: the ability of the paint to stick to the metal.
“What is interesting, everybody says 40-year warranted paint but [with SMPs] the film integrity is 40 years, the chalk and the fade are 30 years,” Knight said.

In the U.S., the paint warranty comes from the paint company (an Akzo Nobel, a Valspar, a Duracoat) and is held by the company that applies it. No paint warranties are transferable. The paint warranty remains with the fabricator.

When there is a problem, it goes up through the chain to evaluate the cause of the failure and who will take responsibility, including the installer.

All roll formers should have available their agreements with the paint company, with the important facets of that language written into their own agreements as a protection for themselves and their customers.

Confused yet? To builders Knight noted: “I think it’s important to deal with a reputable roll former who has the depth to stand behind their product.” 


Once off the production line and on the job site, it’s up to the builder to make sure the panel is handled correctly. Don Switzer offers these job site tips.

Job site storage: “I know you think, well it’s building panels, we can store it outside,” he said, “but building panels are built to be on a building, not to be in a stack … In particular you don’t want water to get between the sheets so it causes the paint to delaminate. The pressure of the stack, and the water forces the water through the paint and makes it delaminate. Once they are on the building, and the water is hitting them, the water is just running off. But when you have the water trapped, that’s where you have a problem.”

Installation: “The key is that you don’t damage the surface,” he said. “The metallic coatings without paint (Galvalume or galvanized) or the metallic coatings with paint are not as hard as the steel substrates beneath those paints. So you want to make sure you don’t compromise the integrity of the painted or metallic surface. Again, once they’re up and they’re not scratched, you don’t have a problem. But if you scratch that product all the way down to the base metal, it’s going to rust because you’ve damaged the barrier placed there to protect it.”


Stay tuned tomorrow, as I share “the rest of the story”…



SMP: Silicone-modified Polyester Paint

In today’s marketplace, most pole buildings are roofed and sided with silicon-modified polyester paint or SMP.

SMPs create a middle ground between PVDFs (Polyvinylidene Fluorides) and polyesters. Also known as silicone-protected and siliconized polyesters, SMPs use polymerized silicone to improve polyester’s chalk performance and gloss retention. Companies initially experimented with varying levels of silicone, and marketed high levels as superior to lower levels, but silicone became less important as the polyester resins themselves improved. Most SMPs now contain 30 percent or less silicone.

Steel Paint LayersSilicone-modified polyester systems vary greatly in quality. Polyester quality outweighs silicone content in importance, but SMPs still outperform straight polyesters in chalk resistance. A more important difference is in pigment type and quality. Some formulations use the same ceramic pigments as PVDFs; others rely on simple inorganics or organics. Since the better resin does little to prevent an organic pigment from fading, paying for silicone is no excuse for going cheaper with pigment.

SMPs vary in gloss from 20-60 at 60 degrees (semi-gloss to medium gloss). Realistic warranties for SMPs vary between 10-20 years and can feature impressive chalk, fade, and gloss retention promises. There are companies which do offer unrealistically long SMP warranties – I would encourage the reading of the actual warrantees closely, before paying extra for a product with a drastically high fade rate over time.

Like polyesters, SMPs are harder than PVDF resins, making them more resistant to rough handling. They are also more brittle, and tiny fractures can form on bends during roll forming. Manufacturers have generally considered these microscopic fractures insignificant, however some companies are warming their SMP coil before sending through the roll former.

Most paint decisions are compromises between performance and costs, with SMP being the middle ground in both as compared to polyesters or PVDFs. Color is an important consideration. Light colors reduce the appearance of chalk, and are readily formatted with inorganics. Some companies will offer polyesters in a light color range, but shift customers over to an SMP for darker ones.

With a chalk/fade advantage over polyesters, and a scratch/abrasion resistance advantage over PVDFs, SMPs are the most widely-used paint system in the non-commercial building market. SMP is still a good paint system – it just allows for more chalking and fading over a given time period than PVDFs such as Kynar®.

Pencil Hardness Tests for Painted Steel Roofing and Siding

In researching the paint systems applied to steel roofing and siding used on pole buildings, I came up with some interesting information.

From an August 2003 story in Metal Roofing Magazine:

“There are dozens of criteria and tests paints are subject to, including falling sand erosion tests, acid tests, adhesion after impact and bending, and salt spray and acid rain simulations. One of the more important characteristics is hardness, or scratch resistance, which is measured in pencil hardness. The test (ASTM D3363) uses pencil leads, ranging from 9H (hardest) to 6B (softest), to determine the hardest that will not scratch the coating. One pencil is the difference between two adjacent lead types.”

OK, I can readily see where this would be fairly important information to know, especially for those who are doing installations – whether a professional builder, or a D-I-Yer.

#2 PencilThe pencil hardness test is very simple to do, gives uniform results, and is dependable because the pencils are graded. The grade of the pencil is determined by the amount of baked graphite and clay in its composition.

I remember graded pencils from my junior and senior high school mechanical drawing classes. I was fortunate to have instructors who would let me draft at my own pace – they would give me all of the assignments for an entire semester at the beginning of the class, and I’d have them all done in a matter of a few weeks. I enjoyed drafting so much, I’d go to school early and skip lunches to be drawing.

Well, those graded pencils come in an assortment of both hard and soft, and can be found in most art or office supply stores. Pencil grades are designated such as H (hardness), B (blackness) and HB (hard and black). The hardest lead would be 9H, followed by 8H, 7H, etc., to H. F is in the middle of the hardness scale; then comes HB, B, 2B….to 9B, which is the softest. The most commonly used writing pencil is a #2, which would be equal to HB grade. It is fairly soft, contains more graphite, and leaves a dark mark.

Here is an audience participation type test which can actually be done at home! It does involve the investment into a variety of differently graded pencils. Once the pencils have been acquired, select one and make a line about ½ inch long on the “outside” of a piece of painted steel. If this pencil scratches the surface of the coating, go to the next softer pencil and repeat the drawn line until the first pencil which doesn’t scratch the coating. Do the test again, and if the same results are obtained, this is the “Pencil Hardness” of the coating.

It is important to understand the degree of hardness of any generic coating may not always be the same. One company’s SMP (Silicone-modified polyester) paint finish will not necessarily be the same hardness as the next.

In my humble opinion, the ability of a painted steel panel to resist scratching is fairly important. What is odd (at least to me) is I have done significant online research, and have only been able to find one company (McElroy Metals) which lists even a single paint system (their Kynar® 500 panels as having a rating of HB to 2H. I’ll keep looking on this one.

Paint Fade

When I went off to architecture school at the University of Idaho in 1975, I needed a vehicle which would be a little better suited to the weekly commute from Post Falls to Moscow. My 1964 Datsun pickup (they were really tiny then) had been OK for motoring around town in high school – but it was getting up in miles and when I was made an offer for it which I could not refuse, it was time to go shopping.

I stumbled upon a 1966 Chevrolet Chevelle SS with a straight body for $300 (yes, I know it would be worth at least 100 times more if I still had it today). It wasn’t perfect – it had a rear window leak, and when I went to the gas station it was “fill it up with oil and check the gas”.

Blue ChevelleThe Chevelle had its original factory paint – Marina Blue Polyester from Ditzler® Automotive Finishes. After nine years of probably being rarely (if ever) garaged, the Chevelle’s paint had faded. Significantly. Chevrolet’s Marina Blue had faded to a bluish tinted off-white.

Paint fade is actually caused by the ultraviolet (UV) rays, from sunlight, which go through the paint and destroy the photons of the color in the paint, almost like a filter. While many believe paint fade from UV rays is the only cause of fade, there are other reasons. The color loss also occurs when pigment is washed out of a paint resin which is pitting or dissolving. Pollutants and other chemical and biochemical residue will cause degradation leading to fading. Things like pollutants in the air (too small for the eye to see, but solid particles in the air which build up over time), bird droppings, salt and insects all contribute in one way or another to the fading of not only my prized 1966 Chevelle, but also to paint fade on pole buildings.

Diligent potential pole barn owners will leave no stone unturned and virtually no concept misunderstood when shopping for a new pole building. Questions get asked like how will the wood be treated to ensure the longevity of below-grade structural members? At what distances will trusses be spaced? But what about paint systems?

Anyone can be expected to grasp basic concepts like fade – bold brown siding which now looks like coffee with two creams is easy to spot.

Fade is measured in NBS or E Hunter units, with 1 Delta E being the slightest color differential perceptible by the human eye. A change of 5 units is slight, and a problem to consider primarily when new and weathered material will appear near each other on a wall or roof. The best performing paints, Polyvinylidene Fluorides (or PVDFs) like Kynar® 500/Hylar® 5000, won’t change more than 5 units over 20 years or more.

When I was first constructing pole buildings, in the early 1990’s, we constructed a backyard garage for an acquaintance of mine – not far from where I live. When the building was just a couple of year’s old, a nearby tree decided to fall on it, entailing the replacement of eight panels of roof steel, as well as the rake trim.

The replacement steel and trims were delivered – from the very same manufacturer as the original order. My construction crew chief called me from the jobsite, after arrival, to ask why we had shipped Charcoal Gray replacement panels, when the original building was Light Gray…..well, the first steel panels were Charcoal and had faded to an ugly Light Gray in only two years!

Polyester paints (like what was used on my friend’s building), offer a broader color spectrum than formulations such as Kynar® 500. However the brighter and darker colors, especially reds and blues (like my 1966 Chevelle SS), are most prone to fade.

While sunlight can’t be removed from the paint fade equation, there are steps which can be taken to minimize paint degradation. Think of the paint on a pole building, like automotive finishes. A good regular washing, with non-abrasive cleansers makes for a starting point. I know of several people who semi-annually give their pole buildings a coat of spray wax after washing. Waxing can provide a shine which rivals polishes, with some advantages.

Waxing doesn’t remove any of the paint’s surface through abrasion, instead it adds an extra layer over the paint finish. This extra layer provides additional protection.

You can’t fool time and it will eventually take a toll on a pole building’s paint color by fading it.

The best solution to minimizing paint fade – invest in a high quality paint system to begin with. Like good, better, best – pole building paint systems run from Polyester, to SMP (Silicone-modified polyesters) to PVDFs.

My recommendation – to have a pole building which looks as close to new as possible in 20-30 years, spend the money for a high quality paint system.