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Tuesday, May 20, 2008

Metal roofs at home in the country

In just a few decades, metal roofing has gone from has-been to major contender in steep-slope commercial and institutional roofing. But it’s the residential market that the industry has been eyeing lately, especially those vast tracts of suburban homes now covered primarily with shakes or asphalt shingles.
Many builders are starting to recommend metal roofs to clients, and for good reason. The low maintenance and long warranties make for satisfied clients. Like any other upgrade, there’s a profit margin involved. And 10 or 20 years down the line, when you bring a customer by to see your work, the home is less likely to have a curling, discolored roof.
But metal roofing runs into a number of obstacles in the residential market. Cost is one, of course: metal roofs generally run more than twice the price of 3-tab asphalt shingles, in the same range as concrete tile and wood shake.
But a bigger concern, especially in tightly built suburban and urban housing tracts, is aesthetic: many homeowners don’t want to flout the dominant roofing style of a community, which is often dark-colored shingles or shakes. Light-colored or unpainted metal can create fears that glare will disturb neighbors. Oftentimes, community covenants actually forbid certain materials to maintain a desired look.
Tellingly, the objection most often heard is that vertical panel roofing looks “too rural” or “too commercial.”
For these reasons, only metal shingles and facsimile products — metal formed and finished to mimic shakes, tiles, or asphalt shingles — have relatively free access to these markets. Vertical panels may end up on custom homes and a few others, but haven’t made a dent in those vast suburban tracts.
But for builders active in less dense suburbs and rural areas, metal roofing is a natural fit. The more open neighborhoods allow for distinctive designs and less stylistic conformity. Brightly colored roofs are less likely to bother anyone or offend community sensibilities. And rural dwellers are more likely to have a first-hand appreciation of the durability and looks of metal.
In some regions, residential vertical-panel metal is an established architectural style. The Texas Hill Country style, the Florida “Cracker” house, the northern New Mexican vernacular, and the rural Southern 5-v crimp look are the best known, but there are areas of the Upper Midwest and West where vertical panels are common. Not coincidentally, these are primarily rural traditions.
For many homes, screw-down panels suffice to make an attractive roof. With good quality products, the exposed fasteners aren’t visually intrusive, and the ribs limit metal’s propensity to oilcan, or warp. Homeowners, however, should keep an eye out for fastener pullout over time.
Where it’s affordable, standing seam is preferable for its cleaner lines and fewer penetrations. Field-seamed panels are the gold standard, but snap-lock and the flange-fastened (nail-strip) panels can lower installation costs.
If the customer doesn’t like the vertical panel look, but is willing to pay for a premium roof, it’s time to turn to shingles — metal shingles. The variety here is huge, ranging from copper tiles and painted metal shingles to products that are almost indistinguishable from tile and wood shake. Metal shingles can also offer a look unlike any other material, including the Victorian stamped style popular a century ago.
Many shingles are installed on a batten system, which makes them ideal for reroofing directly over asphalt or wood shakes, without tear-off. Others require a clean deck.
For most homeowners, metal’s cost is still the biggest obstacle. In new construction, the roof material is often one of the last topics discussed, arising at a time when the client is tired of upgrading. Asphalt shingle roofs are effective, easy to install, and inexpensive, and they’ve convinced most homeowners that roofs should be cheap and replaced every 12 to 20 years. Homeowners might spend big money on triple-paned glass but still insist on a cheap roof.
The fact that the roof represents a huge portion of the building’s visible exterior means it should be handled at the outset. Other than aesthetics, there are several points that can help convince a homeowner.
Value. Depending on the system, a metal roof can last more than 50 years. Its cost should be compared with the life-cycle cost of a series of asphalt shingle or shake roofs, including tear-off and reroof costs.
Fire. Forest and brush fires are a fact of life in many parts of the country, and metal has always been viewed as the premier fireproof roof. Fire officials in the West this past summer were reportedly favoring metal-roofed homes when choosing which to defend. In new installations, the model codes consider metal a Class A roof. More importantly, metal will remain a Class A even after decades of real-world UV and weather exposure.
Snow. Metal sheds snow and can’t be torn off like wood shakes, tiles, or shingles; this makes it ideal for weekend cabins that can’t be checked or frequently maintained. The air gap below most metal shingles can also help keep the roof cold during snowy winters, helping to prevent ice damming.
The environment. More than 20 billion pounds of asphalt shingles end up in dumps every year. Metal’s recycled content averages over 50 percent, and it’s 100 percent recyclable.
Energy. Metal may get hot in the sun, but it performs surprisingly well as cool roofing. Light-colored metal deflects the sun’s heat energy, and, according to a Florida Solar Energy Center study, it can lower attic temperatures and cut cooling costs better than any other material. And new pigments currently undergoing tests will allow even dark-colored painted metal to reflect like light-colored materials.
Metal shingles, whether installed on battens or not, generally create an insulating air gap beneath them that can also reduce heat transmission.
Wind. Most metal systems are thoroughly tested for wind uplift, and perform impressively. Metal products don’t require extra nails or wires to pass; the basic installation is usually the wind-rated installation method as well.
Hail. Virtually every metal roof panel submitted to the UL 2218 hail impact test has passed with the highest rating: Class 4. Other materials perform so poorly their manufacturers have resorted to attacking the test rather than improving the product.
In Texas, insurance discounts are available to homeowners who go with Class 4 materials. Homeowners must sign a waiver on aesthetic damage, however, which has dampened participation in the program.
Weight. Not all homeowners need to consider weight, but for those who do, metal’s featherweight ranking (90-150 lbs. per square, compared to 500-1000 lbs. for tile and 300-400 lbs. for each layer of asphalt) can be indispensable. In particular, achieving the tile look isn’t possible on some structures without using metal facsimiles.
This has been a brief overview of a complex and varied topic. Readers interested in learning more should request literature from the manufacturers in our product profiles beginning on page 38, visit the Metal Roofing Alliance Web site, www.metal-roofing.com, and consult our sister
publication, Metal Roofing magazine (for subscription information, visit www.metalroofingmag.com, or fax your request to (715) 445-4087).

Source constructionmagnet.com

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