Metal Roofing

STEEL VS. ALUMINUM ROOFS: WHAT’S THE DIFFERENCE?
BY: NICK LEE
PRESIDENT AT COASTAL METAL (MIAMI, FL)

As roofers, we know the phrase, “location location location” isn’t exclusive to real estate industry. When choosing between a steel and aluminum roofing system, the location of your project can determine which material will best suit your needs.

Steel Roofing 101

Environmentally-friendly, sturdy and easy on the wallet, Steel is the most common material used in metal roofing. Steel roofs are a solid choice for the vast majority of roofing projects, especially where value is important. Many steel roofing products come with hard-to-beat 40 to 50-year warranties. However, in comparison to aluminum, steel is a lot more susceptible to seawater damage making it a bit undesirable for coastal applications. Over time, moisture from the ocean oxidizes the iron component in steel, creating ferric oxide, more commonly known as rust. Steel manufacturers fight rust formation by coating panels with either zinc or Galvalume in order to form a protective barrier.

Steel roofs offer a number of benefits, including:

• Durability/Gauge – The lower the number, the more durable the metal. Steel panels range from 22 (thickest) to 29 gauge.

• Fast Installation – Steel roofs can be installed quickly. Certain steel panels have clipless, snap-and-lock installation systems that expedite the process.
• Cost Effectiveness – When compared to other metals, steel is the least expensive. A steel roof also saves you money by keeping your heating and cooling costs low. Steel has a higher reflectivity than other roofing materials. In the hotter, summer months it deflects sunlight from being absorbed, and in the winter, acts as an insulator, reflecting and circulating heat from the underside of the roof back inside the building.
• Fire Safety – Steel roofs are completely fire-resistant. A class-A, noncombustible roofing material, steel insulates against sparks and can ultimately prevent a fire from spreading into a home.
• Aesthetic Versatility – Steel is customizable and can mimic the look of wood, tile, slate or shingles. Steel panels can also be painted or designed to complement the unique appearance of a home.
• Environmental Factor Resistance – Steel is impermeable to algae and fungi that oftentimes shorten the lifespan of other roofing materials like asphalt or wood shingles. Steel is not hospitable to pesky critters that tend to take refuge in roofs (termites, rats, racoons, etc.)

Aluminum Roofing 101
Aluminum is among the premium choices when it comes down to metal roofing material. Similar in quality to its more expensive cousins, copper and zinc without the price tag, aluminum is still around 20% more expensive than steel. Offering superior protection from saltwater corrosion, aluminum roofing systems are ideal in coastal environments. Due to its price, aluminum is often manufactured in a much thinner panels than other materials as well. While aluminum roofing material’s strength-to-weight ratio is higher than steel, the factor of cost often results in panels that are too thin for their surroundings. In regions with high winds, hail, or strong environmental stresses, this can result in damage to the roofing material. Properly identifying the environmental strains that your aluminum roof will face will be crucial in choosing the right design.

A few things to know about aluminum:

• As a bare, natural metal, aluminum does not age gracefully, so oftentimes it’s finished with a painted surface.
• Aluminum used for roofing applications tends be very malleable and easy to work with onsite, making it a forgiving material for most installers.
• Aluminum is one of the lightest metals used for roofing. It’s strength-to-weight ratio is among the highest of the “common” metals (that’s why most of the airliners in the sky use aluminum for their air frame), and therefore, a thinner piece of aluminum can often do the job of a thicker piece of any other type of metal.
• Price-wise, aluminum falls somewhere in between most of the finished steels and copper and zinc.

The Steel vs. Aluminum Takeaway
Whether you are a builder in charge of constructing a new home or a homeowner interested in upgrading to a metal roofing system, deciding whether to go with steel roof panels or aluminum roof panels is a valid concern.

Steel and aluminum are dependable, metal roofing materials but there are distinct differences and advantages of both types that one should consider. For example, aluminum and steel are two of the most energy efficient roofing materials on the market; they’re naturally reflective, and usually equipped with coatings that meet LEED and Energy Star compliancy.

In term of cost and weight, steel is a heavier material, more dent resistant and less expensive than aluminum. In addition, steel panels are inherently sturdier and totally fire resistant, even without an underlayment. It is an attractive roofing solution for inland projects and new builds. Aluminum is the better choice for homes or buildings located along a coastline or for jobs that involve retrofitting a metal roof over existing shingles. Aluminum is a much lighter metal so weight would not be an issue if a homeowner or business owner wanted to upgrade their existing roofing system. Aluminum is typically more expensive but it is much more rust resistant. Salt water is corrosive to steel roofs, so anyone living close to the ocean should consider aluminum over steel for this reason alone.

“When choosing between steel and aluminum, think about why you’re opting for a metal roof in the first place,” says Albert Del Sol, project manager at Isaac’s Roofing in Miami, FL. “Structurally speaking, a steel roofing system is sturdier but will never outperform aluminum on the Florida coast where saltwater is known to cause roof corrosion. It’s all about your location, choose your metal accordingly.”

Ultimately, the locale and needs of your project are going to dictate which you use. If the project is near the ocean and not in hurricane territory, the choice will probably be aluminum. If you’re out West and brushfires are a concern, you’re better off with steel. If your concern is the added weight of a metal roof being retrofitted over an old shingle roof on an existing building, then you may want to think aluminum or a light gauge steel.

BY: NICK LEE
PRESIDENT AT COASTAL METAL (MIAMI, FL)

Metal roofing has considerable advantages in comparison to other roofing systems such as asphalt, tile, or cement. Boasting several environmental advantages, a speedy and easy installation process and a lifespan of 40+ years, metal panels have quickly become the most practic al option for both commercial and residential use. Metal panels come in a robust assortment of colors and finishes, and having the option to choose is a major selling point. When deciding on the color for your metal roof, something you should always consider is fading and chalking – different paint colors can have different benefits and identifying your needs is imperative before selecting a color. Rule of thumb when it comes to fading/chalking is that lighter colors tend to fade slower than darker, deeper hues. This can be tied to several unique factors, including pigment concentration, whether the pigment is organic or inorganic, and whether the finishes are matte or glossy. There are several factors that can contribute to the discoloration of your metal roof which we will explore:

What is Metal Roof Fading?

The fact is anything exposed to harsh elements long term such as UV rays, water/humidity, chemicals, pollution etc., will eventually fade in color. When talking about metal panels “fade” occurs when pigments in the metal’s paint coating break down, resulting in a washed out or lightening of the once-vibrant, original color. Organic pigment-based colors on the bolder side tend to fade the quickest. While earthier tones or inorganic, metallic colors such as silver and copper, will fade the least over time.

What is Metal Roof Chalking?

By definition, metal roof “chalking” is the formation of a whitish residue on painted or coated metal panels. Metal roof chalking occurs through a similar process as metal roof fading—as the paint on the exposed metal wears down, it will turn white and appear chalky. Luckily, chalking isn’t always indicative of roof damage but rather an aesthetic issue. However, since the paint is what’s actually protecting the metal, unaddressed chalking can ultimately shorten a metal roof’s lifespan over time.

What Colors are Best to Avoid Metal Roof Fading and Chalking?

Simply put, lighter colors fade slower than dark colors. However, the most important thing to consider when selecting a color is the quality of the paint being used. At Coastal Metal, we only use Sherwin Williams paint.

“Choosing the correct paint and primer can definitely help prolong the life of your metal roofing system” says Mark Macdonald, sales and marketing manager at Sherwin Williams. “Backed by a 10- & 40-year warranty, Sherwin-Williams is a leading provider of metal roof paints, finishes, and coil coatings that will preserve the aesthetic of any metal roofing system—guaranteed. If your heart’s set on a darker, or more uniquely colored roof, my advice it just make sure that you’re using high-quality paint.”

How to Prevent Metal Roof Chalking and Fading

Chalking and fading is a natural reaction to the elements, but there are a set of steps that you can take to lessen their effects.

• Ensuring you select an appropriate color and paint system for your project environment

• Lighter, inorganic paint colors will chalk and fade slower, and it will be less apparent when they do.

• High-quality metal paints, like Sherwin Williams will make a difference when it comes to protecting your roof from fading/chalking.

• Make a concerted effort to avoid overexposure to sunlight, moisture, and other harmful chemicals and pollutants. For example, studies have shown that roofs facing north are exposed to less direct sunlight than roofs facing south.

• When purchasing a dark color roof, consider tacking on a roof warranty that covers chalking and fading.