Let The Light In

Roofing Strategies For Skylights

G.K. Sharman, Writer
Reading Time: 7 minutes
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Skylights, which have been around at least since ancient Roman times, were a fashionable way to brighten residential interiors between the late 1970s and the early 1990s.

Many of those homes now need new roofs. Advances in skylight styles and technology, as well as the trend toward converting attics into guest rooms, home offices or other usable space, are boosting the popularity of “roof windows” once again.

“Proper installation of skylights is critically important to the integrity of asphalt roof shingles and the roof system,” said Paul Casseri, product manager of residential roofing products at Atlas Roofing. “Like all roofing projects, managing safety, design, building codes, installation and integration with other building components is necessary to obtain the desired results. Contractors should always read and follow all installation instructions and refer to local building codes for specific requirements.”

Here’s a look at some strategies roofers can use to ensure a smoother skylight process from selection through installation.

Drip, Drip, Drip

Perhaps the biggest misconception about skylights is that they all leak. Early versions certainly didn’t have a watertight reputation. Whether cracked plastic or faulty framing let in rainwater, or condensation formed inside and dripped onto the carpet, the result was the same: unhappy homeowners.

Properly installed modern skylights shouldn’t leak any more than the rest of the roof or a regular window, experts say. Raised curb designs and factory-manufactured flashings get a lot of the credit, as do advances in installation practices.

“The roof cements and caulks that were typical in many installations back in the 1980s and ’90s are no more,” said Andy Bredesen, a manufacturer’s representative with Preferred Marketing Associates Inc., which represents Wasco Skylights.

A waterproof barrier is a must. Many contractors prefer to use an ice and water membrane rather than standard underlayment around the skylight frame. Ice and water synthetic underlayment may be required in some areas. Step flashing on the sides of the frame also is more reliable than continuous flashing that relies on roofing cement for a waterproof seal.

“The most important thing to do is to have your best mechanics perform the skylight work,” Bredesen said. “Whether the skylight is self flashed or step flashed or curb mount with step flashing, be thorough and conscientious in your work and you’ll avoid most callbacks.”

New Roof, New Skylight?

Skylights should be replaced when a new roof is put on, right? Depends.

Most experts and contractors advise doing both tasks together. Replacing skylights and roof shingles at the same time makes sense, both in terms of time management for the crew and financial outlay for the homeowners. Some roofing contractors feel so strongly about replacing skylights that they write disclaimers into the contract specifying that the roofer is not responsible if the skylight leaks.

Skylights can be manufactured to fit the exact openings of old skylight brands that are no longer in business, Bredesen said.

Casseri also advises installing skylights concurrently with new shingles.

“When all work is done at the same time,” he said, “contractors can assess the arrangement and location of attic ventilation, gutters, plumbing vents and other existing roof-mounted equipment to ensure that the skylights do not interfere with the effectiveness of those roof system components.”

A skylight that’s in good shape, however, may not have to be replaced during a re-roof.

“In most cases, skylights don’t have to be disturbed when a new roof is put on,” said home improvement expert Danny Lipford, host of the nationally syndicated TV and radio program, Today’s Homeowner with Danny Lipford. “But you do have to be careful not to damage them.”

A skylight that is not replaced still needs to be reflashed, he said, and the shingles properly integrated around it. Replacing all of the flashing is essential to maintaining a long-lasting roofing system.

“This is another window that allows light into the home,” Lipford said. “Homeowners should treat it like any other window, though it is subjected to more extreme conditions being on the roof.”

If roofers do replace the skylights, he said, they should be sure to read the instructions for the particular model they are installing, even if they’ve put in skylights before.

Under no circumstances should homeowners attempt to DIY a skylight replacement, Lipford said, “unless they have a lot of skill as a roofer and the ability to understand the details of shingles, flashing and sealant.”

Not Your Grandpa’s Skylights

Customers depend on roofers for more than just skylight installation, so contractors should be prepared to offer advice on skylight location and the latest in style and tech as well.

Location counts, and how the skylight is positioned in relation to the sun can mean the difference between sun splashes and soft light or gentle warmth versus overheating. Skylights on a south-facing roof surface that gets uninterrupted sun all day can serve as passive solar heaters and free illumination — or cause rooms to overheat. North-facing skylights are a good choice for homeowners who prefer a soft, diffused light.

“Contractors should not be wary of installing skylights,” said Salvatore Torquato, sales representative for Supreme Skylights. “Skylights today are so much more technologically advanced than they were even 20 years ago, and more efficient as well. The flashing systems today provide for an easy installation that incorporates ice and water membrane and step flashing for a leak-proof design that cuts down on callbacks.

“Another advantage is that the glazings utilize double-pane insulated glass with Low-E coatings and Argon gas, which results in a lower U-value and greater thermal performance. The skylights also incorporate condensation channels with weep systems to mitigate any condensation that accumulates in high-moisture environments such as bathrooms and kitchens.

“For the homeowner, skylights brighten up dark hallways or corners and just generally provide beautiful, natural light in a home. They can provide natural ventilation in the spring and summer, allowing warm interior air to escape. In the fall and winter months, skylights let in much-needed natural light, as well as warmth from the sun's radiant heat."

Other considerations include how the skylights will affect the aesthetics and architectural lines of the home and whether they will be visible from the street.

In terms of style and functionality, old-style dome-shaped acrylic skylights are a very small percentage of the residential skylight market these days, Bredesen said. Tempered or laminated glass is the norm.

Skylights also don’t have to be square or rectangular. Cylindrical skylights known as solar tubes, sun pipes, light tubes or the brand name Sun Tunnel™ are a way to bring natural light into corridors, stairwells and bathrooms or under-pitched roofs where regular skylight installation may not be possible.

Other recent advances include tintable-on-demand glass controlled with a smartphone app and solar-powered skylights that not only open and close without wiring or electricity but also have built-in rain sensors that close the unit as soon as they detect a drizzle.

For customers who turn an attic into office space, a playroom or an extra bedroom, Lipford said, skylights that “flip out and open as a balcony” are an innovative option. Skylights also can be a method of emergency egress, particularly for homes with finished attic spaces and steep-sloped roofs.

Open Up To Skylights

The experts at Atlas Roofing — a leader in the manufacturing of asphalt roof shingles and roofing products — can help contractors understand the ins and outs of shingling for skylights. Atlas offers technical roofing advice along with information on how to more effectively grow your business. Sign up today for the Atlas Pro™ Plus program to gain an advantage over competitors.