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History of Metal Roofing
The history of metal roofing stretches back to 970 B.C., when the temple in Jerusalem was outfitted with a copper roof. This particular style of roof developed an island identity much later when it became popular in the Virgin Islands.
Metal roofs were valued for several reasons. They were strong enough to resist earthquakes and the strong winds of tropical hurricanes, while presenting a visually satisfying appearance. When coupled with the Dutch-style peaked roof and a decent drainage system, the metal would purify water which could be stored in a container for household use. The metal had the added benefit of being fire-resistant.
Robert L. Merwin & Co., a St. Croix Island based business, was founded in 1892 to import corrugated metal for buildings. They made the product cheaper and much more widely available, which served to increase its use and establish metal roofing as a much more practical and versatile alternative to clay tiles. Popularity for metal as a roofing material has continued to rise rapidly.
The introduction of steel at the turn of the twentieth century, as well as a plethora of advances in the automated manufacturing of metal for construction has industry statistics projecting that the implementation of metal roofing will triple within the next five years. The latest techniques, including automated roll-forming, coatings, sealants, and fastening systems, have dramatically lowered the cost of steel roofing and only increased its versatility as the variety of colors, textures and styles has multiplied.
Types of Metal Roofing
There are two generic types of metal roofing systems for residential use: concealed fastener systems and exposed fastener systems. Generally, exposed fastener systems cost less than concealed fastener systems. Depending on the aesthetic look you are tying to achieve, your trained professional contractor, or Lyon Roofing & Supply can help you choose the system right for you and your roof design.
Galvanized steel is coated with zinc for corrosion resistance. Galvalume steel is coated with a predominantly aluminum alloy, also to achieve corrosion resistance. Both galvanized and Galvalume are available in various grades. The grade is determined by the thickness of the zinc or aluminum coating applied to both sides of the steel. G-60 is the recommended minimum grade of galvanized steel and AZ50 is the recommended minimum grade of Galvalume if it is to be painted. AZ55 is recommended for Galvalume if it is to be mill-finished or have a clear coat.
Other metals being used include aluminum, copper, zinc, stainless steel and terne. Aluminum is used for its corrosion resistance and malleability -- such as its ability to be formed into detailed wood shake profiles. Aluminum roofing always has a paint finish or anodization applied to it for color and extra durability. Copper, zinc and stainless steel more commonly are used without additional coatings.
Copper is used for its durability and characteristic patina. Zinc also is used for its corrosion resistance, malleability and low-gloss gray look. Stainless steel is used to achieve a lasting, bright, silver metallic look or to meet the demands of an exceptionally corrosive environment.
Metal Roofing Installation
Residential metal roof systems require underlayment, and it is critical for three reasons. One is to keep the structure dry during the roof system installation process. Another reason is to provide redundant protection. And third is to keep condensation on the back of the roof panels from saturating roof substrates.
Although for many years, 30 lb. asphalt saturated felt was the standard underlayment beneath metal roofing, many contractors have switched to newer synthetics underlayments that are lightweight and offer more coverage per roll. Self-adhering underlayments can also be used. However, it is critical these products always are smooth rather than mineralized so as not to damage the back of the metal panels.
During installation of the roof, the individual roofing panels are fastened together with special screws that are color coordinated with the metal roof. The fasteners have a grounded washer that prevents water infiltration around the fastener.
Metal Roofing Cost
Although the initial cost of metal roofing is higher, the life-cycle costs are substantially lower than conventional materials.
The decision to select metal roofing is often based upon the fact that the homeowner either doesn't want to or can't afford to replace their conventional roof every 10 to 12 years. Metal roofing, on the other hand, will provide years of low maintenance service life.
In the end, the cost of metal roofing -- while clearly a little more than you would pay upfront for traditional roofing material -- is well worth its price; giving you more than double the lifespan than you would normally receive from traditional roofs.
Benefits of Metal Roofing
Metal roofing has many benefits to the business or home owner, and we've tried to list as many as possible.
It doesn't rot, crack, warp, curl, split, flake, peel, break, burn, or blow off. It's the most resistant roofing material to hail, wind, fire, and freezing/thawing. It looks great, and is available in a wide variety of roofing styles, patterns, designs, and colors.
Metal roofing is lightweight -- most styles are less than one-third the weight of asphalt/fiberglass shingles. Metal roofing saves you money because it is energy efficient, leading to lower A/C and heating costs. It can also reduce the cost of your homeowner's insurance, as well as increase the resale value of your home. It's low maintenance, long lasting and durable, and carries a long warranty. Metal roofing can even usually be installed over your existing roof (reroofing).
Metal Roofing Colors
Manufacturers offer a variety of colors. Lyon Roofing & Supply offers twenty. View available metal roofing colors.
Metal Roofing Pictures
Please follow the links below for examples of residential and commercial metal roofing.
- Residential Metal Roofing Pictures
- Commercial Metal Roofing Pictures
- New Construction Metal Roofing Pictures
- Church Metal Roofing Pictures
Metal Roofing Accessories
Although certain jobs with unusual shapes present challenges that may involve custom panels or flashings, manufacturers of residential metal roof systems typically offer a wide array of standardized accessories. These accessories are designed for eaves, gables, valleys, hips, ridges, pitch changes and roof-to-wall intersections. In some cases, a manufacturer may provide drawings for local fabrication of accessories as an alternative to buying preformed accessories.
Most residential eave details involve a drip edge that will direct water from a roof into a gutter or safely past the fascia. With standing-seam roof systems, the bottom edge of each panel is hemmed to wrap around the starter or drip edge. The standing-seam panels attach to the roof deck with clips and then are fastened at the top of the panels. For through-fastened vertical panels, as well as some shake and tile profile panels that cannot be locked into a starter, a manufacturer usually will provide closure strips and a clear procedure for holding the lowest course tight to the roof.
There are various methods for handling gables, usually dictated by the exact profile of the roofing panel being installed. There are three basic valley styles used with the various types of metal roofing -- a flat valley pan; one- or two-piece valley flashing; and a third valley option, often called an "open valley." There also is a variety of methods used for closing off ridges and hips. Most vertical panels will use lineal hip and ridge caps, usually in 10 lengths.
Situations such as slope changes and roof-to-wall intersections often will require custom-formed flashings to meet the exact roof shape. Manufacturers will provide suggested flashing designs, and you can bend these flashings on a portable brake or work with a local sheet-metal shop to have them custom fabricated. Skylights and chimneys also often will require special flashings though many of the major brand skylight manufacturers offer flashing kits designed to accommodate metal roofing. With regard to skylights and chimneys, it is important to remember there should not be a large dependence on sealants.
Although sealants can be used for aesthetic reasons and as backup water protection, the first line of defense with any metal roof flashing should be the flashing design. Extra security is achieved with sealant and underlayment.
Skylights should be on curbs that put them significantly above the highest point of the metal roof profile. On chimneys, the flashings should be cut into the masonry whenever possible. For roof-to-wall flashings, the flashings should be cut into or extend up behind the wall covering.
Attic vents and pipes should be handled per a roofing manufacturer's instructions. Several styles of pipe flashings are available that were designed specifically for metal roof systems. In some cases, these even will be available in matching colors.
Of course, as any experienced roofing contractor knows, just when you think you've encountered all unusual roof situations, something else comes along. In these cases, basic flashing design principles need to be remembered. It is important such flashings be designed to keep water flowing on top of the metal. However, the best-designed flashings often will feature redundant "backup" water channels beneath the roof panels for added safety and water protection. Another important thing to remember is to not create situations where roof debris, such as tree leaves, pine needles or ice and snow, may be trapped either by or in a flashing and cause water to back up the roof. Again, you should consult roofing manufacturers or The NRCA Architectural Sheet Metal and Metal Roofing Manual regarding the design of special flashings.
Ventilation for Metal Roofing
It is important to always use ridge venting. These usually involve special proprietary pieces or the use of commercially available ridge venting products. Many vertical-seam products are vented through the use of specially formed closure strips that allow airflow between the high ribs of the roof panels. Eave soffit vents are used for air intake. Many people have a misconception that installing a metal roof system increases the need for attic ventilation. In fact, with conventional construction, attic ventilation is critical regardless of the roofing material. A metal roof system does not alter the need for proper attic ventilation.
The important thing to remember at all times is that the cause of condensation is warm moist air contacting a cool surface. The goal of attic ventilation is to eliminate the opportunity for that to happen.