If metal roofing is new to you, you probably have a lot of questions.  In the next few paragraphs, we’ll help you get enough information to make an informed decision regarding your next roof.

What exactly is a metal roof?

When it comes to roofing, there are a lot of choices available.  You may choose your new roof because of the type of building it will cover, the climate or weather, color or style or how long it will last. Whatever your reason, roofing can be a significant investment, and you want to make a wise choice.  That’s where metal comes in.  But if you haven’t had a close look at metal roofing in the past five years, you may need to look again.  What exactly is metal roofing, and why is it better?

Metal roofing is not new, in fact, it has been in use for over 1500 years.  Believe it or not, some of those roofs are still in service today (think European cathedrals).  Yet, many folks still think metal roofing is the rusty stuff on old barns.  Metal roofing solutions today are nothing like that, and are very advanced in both style trends and technology.

Let’s look at the prevalent materials used in modern metal roofing.  Metal roofing is usually made of steel, aluminum, copper or zinc.  Natural metals like copper or zinc, while beautiful, can be expensive, and are usually found in commercial applications, luxury homes, trims or accents.   Most commercial and residential metal roofs are made from steel or aluminum.  The steel used for roofing is given a rust-resistant galvanic treatment (galvalume or galvanized) that significantly improves its weather resistance.  Steel or aluminum is manufactured into rolled sheet metal coils and pre-finished in a factory.  Much like car finishes today, the roofing metal receives multiple coats of baked-on primers, color finishes and UV-resistant topcoats that will last for decades.  Metal roofing can then be formed into panels or shingles with interlocking sealed seams to create a watertight roofing system.  Metal roofing systems include the roof panels themselves, and associated trims such as ridge cap, hip cap, gable trim, valleys, and eave trim for a complete watertight envelope.

Disposable or Permanent Roofing?

You may never have thought of roofing this way, but asphalt, composition or shake roofing are all… well, disposable.  They have a relatively short lifespan of 5 – 20 years, and then they have to be replaced.  So, we pay for them all over again, and shovel the old roofing material off to the dump.  In fact, every asphalt shingle you see today, regardless of price-range, will end up in a landfill in the relatively near future.  Startling thought, isn’t it?  In contrast, metal roofing is one of the most economical and highest value permanent roofing solutions available today, and is 100% recyclable.  Why is metal permanent?  A properly installed quality metal roof can last for the life of your building.  Even after many years of service, metal roofing can be repaired or refinished to extend its life even further.  So your roofing choice comes down to:

  1. Do you want to buy and re-buy, and re-buy short-term roofing?
  2. Or spend a little more to buy a one-time, more permanent roofing solution?

A metal roof can outlast a composition roof by three to four times, making it an outstanding value over its long life cycle.

What about style and color?

Let’s see, shingles – black, brown, tan… 3-tab or sculptured.  Metal, on the other hand, offers enormous variety and possibilities. Many profile shapes, exposed or hidden fastener panels, hundreds of stock and custom colors, metal vintage shingles, stone-coat, panels that look like ceramic tile, clay tile or wood shakes – and the list goes on. Metal has become the chameleon of roofing materials, ensuring that there is a metal roof that is perfect for you.

Is it environmentally-friendly?

Standard roofing choices, like asphalt, composite or wood have been around for decades, and haven’t changed much over time.  Most of these roofing materials can be heavy and heat-absorbing, slowly releasing heat into your attic long after the sun goes down.  Metal roofing with Energy-Star cool roof finishes can reflect away up to 70% of the sun’s radiant energy and dissipate surface heat quickly, keeping your home cooler and lower your air conditioning bills up to 40%.   But the differences don’t stop here.  Standard roofing may only last a decade or two, and then it’s destined for the landfill.  In fact, 11 million tons of shingles per year end up in landfills worldwide, where they will remain for 300 years.  Conversely, steel roofing is a material that is 100% recyclable, and never has to occupy a landfill.  Brand new roofing panels actually contain up to 70% recycled steel.  Metal roofing is lightweight and strong, about a third of the weight of standard roofing.  Because of this, a metal roof can be installed directly over an existing roof without overburdening the roof structure or adding to landfill waste from shingle removal.

Other benefits of metal roofing?

Metal roofing is strong on safety benefits, setting it apart from other roofing materials.  For instance:

  • Metal roofing from Metal Panels Inc. carries a UL-Certified class “A” rating for fire resistance, the highest rating awarded. Being incombustible, many insurance companies offer significant discounts for metal roofing.
  • Metal roofing from MPI carries a UL-Certified class “IV” rating for impact resistance, giving you peace of mind that an attractive roof can be plenty tough, too.
  • Metal roofing when properly installed, can be extremely wind-resistant and will hold up in winds up to 120 mph – well beyond what a shingle roof can handle.
  • While metal roofing doesn’t attract lightning any more than other types of roofing, it has the unique capability to be able to disperse the charge to ground (Faraday Cage principle) making your home safer from lightning and less likely to catch fire.
  • Metal roofing over solid decking makes no more rain noise than other roofing materials.
  • Metal roofing often increases the resale value of your home.

What about roof installation?

If you’re thinking about installing your roof yourself, regardless of the type of roofing material you choose – a word of caution.  A basic roof may look simple enough, but creating a watertight seal around vent openings, skylights, chimneys, crickets or valleys should best be left to a professional installer.  They can recommend the correct roofing solution for your structure.  If you want your new roof to be watertight and guaranteed,  you need to hire a certified and insured professional for the job.  Get quotes from two or three reputable companies, and check their references.  Have contractors explain their quotes, and read the fine print to make sure there aren’t any critical exclusions. Read the manufacturer’s warranties to see if they really stand behind their product.

As you can see, metal roofing has many advantages.  It has factory finishes designed to last for decades. There are nearly no limits to color or design.  Metal is safer, stronger and lighter than any other roofing material.  Metal roofing benefits our environment and saves energy.  It most likely will be the last roof you will ever need.  And, of course, you can choose metal roofing because it simply looks great.  So, making the right choice may be easy after all.  Make it metal roofing by Metal Panels Inc.

MPI Panel Finish 101

A few months ago, I was driving north on I-35 through Kansas at sunrise. It was a picturesque rhythm of farmland occasionally syncopated by an old barn near the highway. These old barns had outlived their usefulness, and had degenerated into roadside billboards painted on their corrugated metal roofs. Even the advertising was a thing of history now. Rusting and fragile, the barns were ghosts of their former purpose. I couldn’t help thinking of how different metal panels are today, and how much longer they will last.

Today’s metal roofing and metal buildings may seem to be closely related to those old metal barns strewn along rural highways, but nothing could be further from the truth. Over the past decade, metal corrosion technology and paint chemistries have catapulted metal panels into a truly archival construction material of choice. To understand the quality, durability and beauty of current metal products, we’ll take a look at the current paint coating technology, and the coil coating process that makes these new panels so amazing.

At the most fundamental level, great metal panels begin with corrosion resistance. Surprisingly, this is NOT the primary function of the paint; rather, corrosion prevention begins as a pre-treatment to the metal itself. Panels are made from metal coil stock, and must be hot-dipped in a galvanize or galvalume process, cleaned, etched and chemically treated with either zinc phosphate, chrome-based or dried-in-place compounds before painting. These treatments chemically alter the surface of the metal creating a corrosion-resistant metal with a much-improved surface for paint adhesion. The most favored treatment for coiled steel today is galvalume for it has been tested to outperform galvanized steel in many weather environments. The challenge is that the very treatments that make panels corrosion-resistant, also make it the most difficult material to paint. Special surface preparation and uniquely formulated primers are necessary to achieve excellent paint adhesion.

Although the processes vary with different paint formulations, pre-treated metal usually receives a primer and topcoat and even a final UV coating to complete the finished, pre-painted coil. Let’s explore this process in more detail.


Once the metal coil has gone through the pre-treatment step, a primer coat is applied. In the past, epoxy or epoxy-esters were commonly used. Today polyester, polyurethane or acrylic water-based primers are preferred for their flexibility and resistance to ultraviolet light. Some coil coaters, use unique, chemically-active primers to improve the bond between steel and coatings. Sherwin-Williams Corporation uses their patented chromate-activated primer to chemically alter the surface of the metal for better adhesion properties, and enhance corrosion resistance as well. Although only 0.25 mils thick, the primer is one of the most critical elements to panel longevity.

The topcoat is the finish that gives the metal its color and sheen, and it’s most important function is to protect against weathering and UV exposure. There are many different formulations for this topcoat, and these choices are a balance between price and performance. There are economy formulations best suited for interior or low exposure applications, to advanced coatings proven to handle the harshest of environments. In general, coatings are primarily made up of a pigment, resin and solvent, although we differentiate them by their resin type. Polyesters are generally considered an economy finish, primarily used for soffit, signage, industrial or agricultural applications and have a relatively low exposure and UV resistance. Newer polyester formulations, especially those blended with ceramic pigments offer outstanding performance improvements, although still not at top performance levels. Vinyl-plastisol coatings offer a unique thick film surface and handle slightly more UV and environmental exposure than polyesters. Silicone-modified Polyester resins offer significantly more UV resistance (the higher the silicone content the better the finish performance), and better suited to handle environmental exposure including humidity, salt air, acid rain, air pollution or agricultural hazards. The current benchmark standard of the industry is a 70% PVDF, or fluoropolymer resin, such as Kynar 500 or Hylar 5000. PVDF is usually specified as a two-coat system, although special paint features may cause the finish process to be up to four coats. This finish has outstanding weathering properties and handles high levels of UV, humidity, salt air and more. Metallic finishes like the Fluropan Classic II (Sherwin-Williams) contain metal flakes or oxides to create the metallic depth, and therefore require an additional clear PVDF topcoat to protect against oxidation and ultraviolet light. Metallic finishes are created using either aluminum flake or mica powder. The mica powder finish tends to be more uniform in appearance. Unique to metallic panels, care must be taken when installing the panels because the finish is directional; panels will appear to have a different depth or shading when viewed from opposite directions. For this reason manufacturers mark the back side of these panels with arrows, to ensure all panels are installed in the same direction. This directional characteristic of metallic panels is called “color flop” and is caused by the method of continuous painting which lays down all the metallic material at the same angle. If a panel is inadvertently “flopped” during installation, the metallic grain will be going a different direction from the others, causing the panel to look significantly different from the rest. New two-toned texture paint and sand-coat finishes round out the wide range of product looks available.

Topcoat finishes are created not only for appearance, but to protect against exposure conditions of sunlight, heat and moisture. Inevitably, weathering will degrade all paint over time. The better the weather resistance of the finish, the longer the life the panel will have. Often, we ask, “How long will the finish last?” when we really mean “How long will the finish retain its original color and gloss?” While the panels may have a long life beyond its original “like new” appearance, the finish performance is based on pigment stability and resin durability. Ultraviolet light, the real foe of panel finish, chemically breaks down the coating. UV exposure will cause fading, which occurs by the gradual breakdown of the pigment by the sun. Depending on finish and color, fading might appear as a bleaching away of the original color, or may exhibit a lateral shift from one color toward another. Organic pigments may be more susceptible to fade than ceramic pigments. Coil coaters may indicate whether the finish pigment is organic, inorganic or ceramic, and should specify if the pigment is a blend of the pigment types. Chalking, another common finish failure, is caused by the breakdown of carbon bonds in the finish and exhibits a white, powdery and irregular substance on the panels.

All certified paint finishes have been real-time or accelerated-exposure tested and warranted for a specific period of time. Most testing and certification is done today base on accelerated-exposure testing; this type of testing is far from accurate, since the rate of paint failure is not linear and the exposure to the elements will vary. Additionally, these warranties need to be studied carefully, for they differ widely. The three key warranted characteristics are film integrity (the coating’s long-term ability to adhere to the metal), weathering (gloss, chalk & fade in specific Hunter units), and corrosion resistance. Depending on your location and proximity to environmental hazards, corrosion warranties may not be issued. If required, check for products that carry a corrosion warranty in a seacoast or high-chemical environment.

One warranty may offer a comprehensive manufacturing defect coverage, while another may merely guarantee that it is “paint”. Therefore, one must look beyond the 25-year or 40-year bold type to see what the warranty actually covers. Conservative warranties such as Berridge’s 25-year PVDF, actually warrant against a measurable amount of appearance chalk or fade, even though their protective qualities will last much longer.

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2018 Rebate Extensions

See Sections “Insulation”, “Roofs”: