Metal Roofing & Siding

How to Select a Residential Metal Roof

Today’s residential metal roofing comes in a wide variety of styles and designs. When choosing a roof for your home, make sure that the product’s design is appropriate for your home’s construction. Most metal roofs will require solid decking (or, frequently, an existing shingle roof) and some can be installed over lathe boards or over wood shingles on lathe. Some of the more textured designs can even be installed over slate and asbestos roofs. Next, choose a product with an appropriate appearance for your home and neighborhood. You can find quality metal roofing with about any appearance, whether it is standing seam or a facsimile of shake, slate, tile, or standard shingles.

Metal roofing is made from a wide variety of metals including galvanized steel (which is zinc coating on carbon steel); galvalume steel (aluminum and zinc coating on carbon steel); exotic steels such as terne and stainless; aluminum; copper; and rolled zinc. Each metal has its own properties and the type of metal used is sometimes dictated by the design of the roofing panel. When making a wise investment in metal roofing, consider all the available options. Many consumers assume that all metal roofing is steel. However, most consumers would choose a permanently rust-free aluminum car over a steel car of similar cost; it makes sense to consider non-steel options for roofing as well.

While residential metal roofing is enjoying ever-increasing popularity, some products are fairly new. As you evaluate various products, find out how proven they are. Inquire about the systems’ flashings and accessories. Look for proven, pre-formed accessories from the manufacturer. It is particularly important to investigate how the valleys are installed. Look for an “open” valley system which carries water on top of the metal panels rather than a “closed” valley which carries water on hidden channels beneath the panels. The hidden channels on “closed” valleys have been known to clog with ice, snow, tree leaves, pine needles, and other debris, causing water to spill over the channels and infiltrate the roof system.

Metal roofing should be installed without dependence on the underlayment beneath it. However, metal roofing can develop condensation on its bottomside during certain climatic conditions. Therefore, it is jeopardizing the durability of your roof system to use a product which does not specify a quality underlayment such as 30-pound felt or one of the new polyethylene-based underlayments. If you are in an area prone to high humidity or salt air and fog, give special consideration to rust-free metals such as aluminum, copper, and zinc. Weather conditions can create the retention of condensation between the panels and the underlayment. Particularly with steel products which rest on or near the substrate such as standing seam, 5-V crimp, and low profile steel shingles, this condensation can cause them to rust from underneath. Keep in mind that failures with steel roofing occur from cut edges on the back side of the metal and rarely from the front weather side.

Because quality metal roof systems have panels which actively interlock with each other, most metal roofs are known for their wind resistance. Be sure to inquire what wind and uplift tests the systems you are considering have undergone and passed. The better products have passed 150+ mph wind-driven rain testing and/or UL 580 uplift testing exceeding 90 psf.

Some insurance companies in select states are now offering premium discounts to homeowners who choose roofs which have passed U.L. 2218 Impact Resistance testing. This test is done in four levels, with Class IV being the most severe level. Particularly if you are in a hail-prone area, it makes sense to find a product which has passed this test. Additionally, some shingle facsimile products offer backer boards to provide extra rigidity for roof areas subject to heavy foot traffic, falling tree limbs, etc. Also, look for products warranted to not loose impact resistance with age and to not chip due to hail or leak due to hail indentation or perforation.

Metal roofing can help to reflect heat and keep homes naturally cooler in warm weather. With steel, copper, and zinc roofing, energy efficiency is achieved primarily when the metal is unpainted and treated to retain its bright shininess, or when it is painted with a bright metallic or white coating. Aluminum, however, inherently reflects radiant heat. Testing done on aluminum roofing has shown it to be efficient even when painted in dark colors. This makes aluminum desirable because most homeowners do not want a white or metallic-looking roof.

Make sure that all fasteners (and other components) are of a metal which is compatible with the roofing itself. Look for a system which has concealed fasteners. Even with today’s neoprene washers and other methods of keeping moisture out of exposed screw and nail holes, any exposed holes through the panels are potential areas for water to enter the roofing system. Any water which infiltrates can, with steel products, lead to corrosion of the roofing and fasteners. Also, many metal roofing systems use “clips” to fasten the panels rather than “through fasteners” which attach the panels directly to the roof. The clips allow for expansion and contraction of the metal. Otherwise, expansion and contraction might “wallow-out” the fastener holes or cause the fasteners themselves to back out of the roof. Clips are very important to standing seam panels which sometimes have great length to them. They are also a factor with various shingle and tile systems though some heavily textured products have an inherent “accordion” effect which allows the metal to freely expand and contract without trouble.

Metal roofing, especially steel, is dependent upon a good coating for long term durability. Most product warranty lengths are determined by a combination of the metal and the coating which is used to produce that product. There are many types of finishes available and, hence, a wide range of quality. Finishes such as acrylics and siliconized polyesters are good for commercial applications where periodic re-coating for a different “look” occurs. Other finishes such as PVDF Hylar and Kynar coatings have longer lives, making them ideal for residential applications. These coatings are widely specified by architects who respect them for their long lives and color retention. Look for a finish which has proven the test of time. Look also for a finish which is warranted against such things as fading, chalking, coming loose from the base metal, and chipping due to impact.

As with any building product, success of the overall project is dependent upon proper installation. Look for products which have detailed installation instructions from the manufacturer. Look for a contractor who has substantial experience with the product you are choosing or has undergone installation training from the manufacturer. Metal roofs do not all install in the same manner. Be sure to check references of past jobs done by your installers and make sure that they have the proper licensing and insurance to work on your home.

Metal roofing is a wise investment in your home. Today’s numerous product offerings provide homeowners with a wide choice of looks and qualities. By making the proper product and contractor selection, you will substantially increase your home’s value, beauty, and comfort.

Call NSS Exteriors for a free on site quote to repair, replace or install a new residential metal roof. For details on specific options, pricing and installation, please contact us online or call 708-385-5815.

Some examples of our work:

Types of Residential Metal Roofing and Siding:

  • B-6 Panel
  • Batten Seam
  • Bermuda Roof Panel
  • Board & Batt Panel
  • Cee-Lock Panel
  • Classic Shingle
  • Colonial Siding
  • Curved Tee-Panel
  • Curved Zee-Lock Panel
  • Deep Deck Panel
  • Double-Rib Panel
  • Fish Scale Shingle
  • Flat Seam Panel
  • Flush Seam Panel
  • Fluted Fascia Panel
  • FW-12 Panel
  • High Seam Tee-Panel
  • Insulated Metal Panels
  • "M" Panel
  • "R" Panel
  • Rustic Shake
  • S-Deck
  • Spanish Tile
  • S-Tile Panel
  • Tee Panel
  • Thin-Line panel
  • Vee-Panel
  • Victorian Shingle
  • Zee-Lock Standing Seam

Metal Roofing FAQ

What is the cost comparison between a metal roof and an asphalt shingle roof?
The cost of a metal roof cannot be readily compared to asphalt for various reasons. The condition and type of roof would have significant bearing on the overall cost, as would the "profile" or style of metal roofing you would choose. When considering metal vs. asphalt, you are basically choosing between an investment (metal) over an expense (asphalt).

Will a metal roof increase the likelihood of a lightning strike?
The answer to this question is "absolutely not". Although metal conducts electricity, lightning is not drawn to it. It's unusual for lightning to hit buildings. Lightning typically strikes the highest object in an area. That's why it often strikes trees, power poles, antennas, and towers.

But if your home were hit by lightning, your metal roof would disperse the energy safely through the structure. Since metal roofing isn't combustible or flammable, it's a low risk and desirable roofing option where severe weather is concerned -- especially for lightning.

Are metal roofs loud?
This may surprise you -- metal roofing is often quieter than an asphalt shingle roof. When installed with solid sheathing, a metal roof on your home will actually silence noise from rain, hail and bad weather better than other roofing materials.

Is a metal roof hot?
Metal reflects 70% of the sun's energy. This minimizes heat retention and as a result less heat is transferred into the building's structure. Further, 1985 research by the Florida Solar Energy Center showed that metal experienced a 34% less heat gain than asphalt shingles. Results indicate that metal roofing offers a similar effect on R-11 insulation on top of the roof during sunny day conditions.

Will my metal roof rust?
Today's metal roofing systems are built to last. Steel metal roofing has a "metallic coating" made of either zinc or a combination of zinc and aluminum. This metallic coating prevents rust from forming and is bonded to the steel at the factory. Paint is then applied over the metallic coating to provide the long-lasting color homeowners desire.

Will hail dent my metal roof?
A metal roof can withstand decades of abuse from extreme weather like hail, high winds, and heavy snow. In unusual cases, very large-sized hail has been known to dent metal roofs during extremely heavy storms. But, a typical hail storm will not dent your metal roof. Today's systems also have a 120-mph wind rating (equal to an F2 tornado), meaning your metal roof is also safe from wind gusts that can accompany hail storms.

Can I walk on my metal roof to clean gutters?
Many people think you can't walk on a metal roof -- but the truth is that you can safely walk any metal roof without damaging it. Before you walk your roof, however, we recommend you talk to your installer first. They will have the details on how to walk the roof.

Do I need to remove my existing roofing material?
One of the benefits of metal roofing is that it is lightweight, which allows it to be installed over existing roofing material. However, the answer to this question ultimately depends on your local building code requirements and the condition of your current roof's substructure.
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