Home House & Components Parts of House Roof
Innovations aim to make roofing materials more lightweight, durable and easier to install. Here, a team of contractors discusses recent developments. ASA Roof Sheet
Things have changed since the Greeks and Romans used overlapping tiles as roofing materials. They weren’t unlike the clay and ceramic tiles you see today on Mediterranean and traditional Japanese houses, but whether on ancient or modern roofs, tiles are heavy and unwieldy. Moreover, as I discovered while living in Japan, they can fall during an earthquake. I almost got beaned during the Great Hanshin quake of 1995.
North American homes typically sport simpler roofs made of asphalt composite, metal or wood, and while these materials are more lightweight, cheaper and easier to install than tiles, there’s room for improvement. “Our favorite innovations in roofing,” says Niki O’Brien, the Operations Manager for a Colorado roofing company, “are the energy-efficient improvements we have seen over the last decade.”
We assembled a forum of contractors and roofing experts from across the country to discuss trends in roofing technology. Recent developments help simplify installation, improve efficiency, save money and increase a roof’s lifespan, so they’re worth knowing about.
“Recently, we have seen an increase in ‘cool roofs,’ which are just white or light-colored roofing or roof coatings,” says O’Brien. Climatologists have determined that ice and snow cover in the polar regions help keep the planet cool, so applying the reflectivity principle to residential neighborhoods makes sense. Cool roofing, says Josh Rudin, a certified restorer from Phoenix, AZ, helps reduce the “heat Island” effect in warm, sunny regions like Arizona.
What’s good for the climate in general is also good for the home. O’Brien remarks that “studies show that by reflecting the heat on your roof rather than absorbing it, you can cut your energy bills by up to 15%. Reflective roofs are typically achieved through metal roofing, a flat roof membrane, or a white roof coating. Unfortunately, white or light-colored asphalt shingles aren’t as popular and don’t blend as well visually.”
Mike Larsen, owner of a roofing company in Grand Blanc, MI, is excited about thermoplastic shingles that essentially allow a roof to ‘self-heal.’ “Scratches and other damage are sealed when the sun heats the material, which separates the bonds. As the shingles cool at night, the material re-bonds, closing up any scratches or damage caused by weather.”
“In general, the ‘self-healing’ trend has also extended to roof coatings,” he continues. “New coatings like RenoTec keep dirt and grime brought by rain and snow off the roof by preventing them from adhering to shingles. This also prevents moss or mold from developing as well.”
Tesla has been producing and installing solar roof tiles since 2016, and other companies have followed. Jay Sanders, a contractor from Maryland, notes that solar tiles and shingles are less efficient than solar panels, but they can still convert 15 to 18 percent of incident sunlight to electricity.
But are they really roofing? “Solar shingles are roofing in the same way that a poncho is a raincoat,” says Rudin. “These systems are functional but don’t have the test of time on their side yet due to how new they are in the marketplace.”
“The idea seems great,” says O’Brien. “But we just haven’t seen customers implementing it in real life. We have been in roofing and exteriors for over a decade and, to date, have only seen one home utilizing this technology.” She cites cost as a possible reason for the lack of interest.
Before installing any type of roof covering, roofers first staple down an underlayment to provide extra insulation and leak protection. Until the 2000s, the materials of choice were roofing felt or tarpaper, but since then, synthetic underlayment has become just as popular, if not more so.
Synthetics are manufactured using polyethylene or polypropylene plastic, and they offer several advantages. They are lighter, stay down better in the wind, absorb less heat, and stay flexible in the cold. They are also safer to walk on, which is good news for workers on high roofs.
Synthetics come in various thicknesses, and the thickest cost 30 to 40 percent more than felt. Some of the thinnest cost less than felt, but thinner products tend to tear out and can be punctured by imperfections in the decking.
Metal roofing panels and shingles come in various colors and are easy to install. Because metal is fire-resistant, they can earn homeowners a reduction on their insurance. However, one of their downsides is that metal, by itself, doesn’t provide much insulation. This prompted O’Brien’s company to experiment: “We recently completed a multifamily neighborhood of roofs in our Colorado mountains. Under the metal panels, we added specialized insulated foam boards. Although we haven’t had a chance to follow up on the results, I have no doubt that they saw improved energy efficiency over our brutal mountain winter months.”
Insulated metal roofing panels have been widely available since the 1960s. They offer the benefits you would expect from the extra insulation, but at nearly 10 pounds per linear foot, they are heavy and may require extra support.
Spray foam (SPF) roofing has also been around since the 1960s. It’s basically the same polyurethane foam that is commonly used for insulation, although the roofing material is a denser, closed-cell formulation. In fact, SPF roofing’s R-value of 6.7 per inch is the highest of any roofing material, according to Sanders.
Besides being a good insulator, SPF roofing has a number of other benefits. It’s easy to install, but not generally DIYable, according to Rudin. “Installation not only takes specialized equipment to operate, but also a lot of practice to get good at.” SPF roofing is self-flashing, which means it automatically conforms to irregular shapes around vents, skylights and HVAC units. An SPF roof lasts 20 to 30 years, and when it wears out, you can simply re-cover it.
Because they don’t shed water as easily as sloped roofs, flat roofs need the protection of a continuous membrane. Single-ply PVC membranes were common from the 1960s on, but they tended to shrink, crack and leak chemicals into the soil over time.
Thermoplastic polyolefin (TPO) membranes, introduced from Europe in the 1990s, have largely replaced PVC. The membranes are 10, 12 or 20 feet wide, and during installation, workers heat-seal the seams to create a continuous barrier. Some membranes are black, but white ones are more suitable for hot climates because they can reflect sunlight.
TPO roofs have an average lifespan of 30 years, costing from $6 to $12 per square foot to install.
Slate roofing isn’t new; it has long been a designer roofing material known for its longevity and curb appeal. It isn’t more mainstream because of its weight, which requires a more robust structure than other roof coverings.
Slate Tec is a new product promoted by Andrew Prchal, president of Gunner Roofing. It “allows for a lightweight installation and easier maintenance options” because it incorporates an interlayment that reduces the actual slate amount in each tile. This allows the product to be lightweight without compromising its structural integrity. “This means that someone doesn’t have to deal with major structural design changes in order to get the look they want with slate.” (Prchal emphasizes that Gunner is not associated with Slate Tec, and he offers this recommendation in a purely informational spirit.)
3D roofing is “a new concept that has transformed the roofing systems,” says Sanders. On one front, engineers use 3D imaging techniques to design complex roof systems; on the other, they use 3D printing technology to produce tiles and other materials.
A YouTube video uploaded by Paul MH illustrates the usefulness of 3D printing techniques. When a windstorm blew tiles off his roof, destroying them and leaving a gaping hole in the roof, he was able to patch the hole using 3D-printed plastic replacements. Shamrock Roofing and Construction notes on its website that this technique successfully creates affordable roofing options for lower-income populations.
Anthony Perera, who founded a major air conditioning servicing company, wants builders to be aware of virtual inspections, so he created the website Inspected.com to help make them more accessible.
“With virtual inspection, roofers can experience same-day virtual inspections and instant permit approvals, enabling contractors to save time and money,” he says. This may make traditional onsite inspections, carried out manually by walking on the roof, a thing of the past.
Virtual inspections can be carried out by drone or aircraft, with the latter method being the most common. They allow roofers to schedule inspections online, get results instantly and make necessary changes quickly — sometimes on the same day. This speeds up roofing projects and reduces labor costs.
At a cost of $21 to $25 per square foot, solar tiles and shingles are pricey, but depending on type and brand, slate can be even pricier, costing as much as $30 per square foot.
If you’re wondering what the cheapest roof style is, that would be asphalt rolled roofing at $0.50 per square foot.
Cedar, wallaba and teak shingles are attractive and fairly easy to install, but they require more maintenance than other types of roofing to prevent mold, rot and water damage. With proper maintenance, they can last upwards of 30 years.
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