For a long time, your only option for roofing materials was asphalt shingles or...asphalt shingles. Few other choices were available, and if you wanted a different roofing material, you had better be prepared to pay big bucks for it.
Not long ago, standing seam metal roofs were only a figment of the imagination in the minds of average homeowners. Most were confined to commercial buildings or very cool, avant-garde residential structures. Now, you're seeing them pop up on every block.
Composition Isn't Everything
Don't get me wrong. Asphalt and composition shingles do have their high points, and they aren't going away anytime soon.
For one, if you want to purchase a dead-cheap roofing material, asphalt and composition tend to be the way to go. One problem with asphalt is that, being derived from petroleum, prices of the shingles do vary. Another thing: if you have ever cleaned out your gutters (assuming you have asphalt shingles), you know quite well how these shingles have a propensity to slough off the upper mineral-based surface. After enough seasons, conventional shingles have literally been worn down to the core.
Standing seam metal roofs are a completely different animal. Not only is the type of material different but the size and shape of the material and its installation method are different, too. Many homeowners find that the higher initial cost of this type of roofing will pay off in the end because of its greater durability and reliability.
Not Just Metal, But Standing Seam
There's metal roofing, and then there's a particular type called standing seam metal roofing.
Houses in your neighborhood with metal roofs most likely are of the standing seam variety. Continuous panels run from the ridge of the roof all the way down to the eaves. Between the panels are seams connected by fasteners which are raised above the level of the metal roofing. This is where we get the term standing seam, because the seam is raised or standing, as opposed to flush-mounted.
- Seam Fasteners: These seam fasteners might be anywhere from 0.5" to 1.5" high. Because these fasteners are concealed, you only see a smooth continuous ridge extending from top to bottom.
- Pre-Formed vs. Site-Formed: Roof panels can come either pre-formed or site-formed. Pre-formed panels are created in an off-site factory. Site-formed panels are created from rolls of metal that are run through mobile forming machines which crimp the metal into rigid panels.
- Composition and Width of Panels: 12 to 19 inches wide, panels are usually made either of Galvalume-coated steel or aluminum.
High Seams: One great advantage of standing seam metal roofs is contained in the name itself: seams, the weak point in any roof and a potential entry point for moisture, are raised above the level of the roofing panel. You can't say this for composition shingles.
Fewer Seams: Because the metal panels run unhindered from the top to the bottom of the roof, not only are there no horizontal seams but in total the roof has a far fewer number of seams.
Tough: Yes, metal is tough--very tough--but it's not impervious to all hazards. The sheet metal in this type of roofing can be penetrated by heavy falling limbs or dented by a severe hailstorm.
"Cool Roof": All metal roofing in general is considered a "cool roof" by the US Environmental Protection Agency. This is because metal roofing can be painted any color, including colors on the lighter end of the spectrum which will prevent solar heat gain.
Sleek Looks: Standing seam roofs are perfect for certain types of contemporary or country-style houses. Due to the smooth, straight lines, these roofs give your house an "industrial" feeling, yet with a modern flair. These are not the rippled tin roofs that you might remember from warehouses of the past.
Colors: I mentioned this earlier, but only in terms of lighter, sun-reflecting colors. But what about style? Metal comes in a decent array of colors: grays, browns, forest greens, earthy reds. Perhaps this isn't the full palette of colors as you might find at a paint store, but it's more than you'll find with composite/asphalt shingles.
Fewer Roofers: Shake a tree and a hundred roofing contractors who install conventional roofs will fall out. But far fewer contractors install metal roofing, and fewer still install them well. This means that you will be searching longer for a good roofer and that total project cost may be higher because competition in the market is lessened.
Not Good For Flatter Roofs: "Roof pitch" refers to the angle of the roof's slope. Certain types of metal roofs do not lend themselves well to flatter (or completely flat) pitches. John Roper of Vertex Roofing tells us that it is
100% true that snap-lock panel metal roofs are not advisable for roofs with a pitch of 2:12 or less (2 feet of vertical rise for every 12 feet of horizontal rise). However, with a better quality mechanically seamed panel it is no problem to go to a 1/2:12 pitch. You can even bump the seams up to 2" with a butyl seal for those applications.
It's important to note, too, that when you get to these lower pitches, you're also below the recommended minimum pitch even for conventional shingles. Generally, these safely go down to a 4:12 pitch, with some shingle manufacturers warranting their product down to 2:12.
Cost: Metal is considered a moderately-expensive roofing material (more expensive than conventional shingles, but less than high-end slate or copper). However, metal's higher cost can be amortized via its longer lifespan.