Should You Use Metal for a Gable Roof?
Metal roofing today is an increasingly popular choice both for new constructions and roof replacement. Studies show that metal roofing gets over 11% of the market, second only to asphalt shingles.
Metal Roofs are Durable
With an expected lifespan of 40 to 70 years, some metal roofs that are properly installed (by professionals) will last as long as the house it covers. Since a roof with asphalt shingles typically lasts between 12 to 20 years, the advantage is quite obvious.
Metal roofs will also withstand wind gusts of 140 MPH (210 KPH), they’re a Class A fire-resistant, and also resistant to insects, mildew, and rot, and will not corrode. A metal roof will also save you time and money on seasonal maintenance.
As far as the product warranty, it varies between manufacturers and product quality from a limited warranty of 20 to 50 years, with the paint finishes for up to 30 years.
Although it has a very low insulation R-value, the ability of metal roofing to reflect radiant heat from the sun also translates in savings towards the air-conditioning in the house. This low R-value can be compensated, however by installing it over rigid foam insulation or by using a dead-air space between the metal roofing and the roof deck to minimize heat transfer.
Most metal roofing material can be installed on a minimum roof pitch of 3-inch per foot without leaking, which is another advantage it has over the asphalt roofing.
They Come in a Variety of Styles and Colors
Compared to the corrugated tin roofing used on barns in the past, metal roofing now comes in an array of choice from tin, aluminum, zinc, galvanized steel, or copper, in all sorts of colors, finishes, and shapes. The two most common metals used in residential roofing are steel and aluminum which are both designed to hold their paint finishes well. Figures 1 and 2 show two different corrugated metal roofing.
Even if a large percentage of homeowners living under metal roofs have the more traditional standing seam roofing (or vertical ribbed panels), there are a lot more style options out there to choose from. They’re also manufactured to imitate more traditional wood shakes, slate or clay tiles, or any other different looks, also using multi-layer finishes. See Figures 3 and 4.
Even with the increased cost of specialized tools, equipment, and many more hours of installation labor, a metal roof can still cost over 10 times more than an asphalt roof. So in the end, it must provide you with many years of service to recoup the cost of the investment, even if the asphalt roof ends up requiring two or three roof replacements during the lifespan of the metal roof.
Metal Roofs Can Be Dented
Metal roofs are designed to withstand abuse from many years of heavy snow and ice that tend to slide down the metal slope. Except for a few types that are guaranteed not to dent, most of them are prone to be dented by large hailstones or falling branches, a chimney sweeper cleaning the chimney, or a plumber working on a pest pipe and for some types, walking on the shingles will damage them. Denting is a lot more likely to occur with soft metals such as Aluminum or copper than steel roofing. So keep this in mind when choosing your roofing.
Metal Roofs Can Be Noisy
When choosing to install a metal roof, it could be advantageous to ensure having the roof deck covered over with 3/4-inch plywood and an insulation material with sound-reducing qualities to reduce the drum pounding noise during a rainstorm or hailstorm, that would sound like you’re inside a drum. These added sound-reducing layers, however, should be factored in when calculating the overall cost of the roof.