how to extreme

Upgrade a Roof with Architectural Shingles

Construction How-To, Roofing February 9, 2015 Sonia


One of our recent EHT projects was a “roof-over” in which we covered an existing single layer of three-tab asphalt roof shingles with architectural shingles.

In roofing, the term “architectural” generally means the shingle has a three-dimensional design and construction. True architectural shingles (also called “designer” shingles) will have more than one thickness to create a shadow line that gives the roof the appearance of slate or wood shake. Not only does the three-dimensional design enhance the look of the roof, but the extra thickness of the shingles provides additional weather protection.

“Asphalt shingles are aesthetically diverse and come in a wide range of styles and colors that will enhance the look of your home,” says Reed Hitchcock, executive vice president for the Asphalt Roofing Manufacturers Association (ARMA). “Designer shingles can display a more natural appearance, and can also match metal, cedar and slate materials that are more expensive. Meanwhile, you’re still getting the durability and easy maintenance that comes with asphalt shingles.”

A ladder stabilizer will hold you steady.

A ladder stabilizer will hold you steady.

For our roof-over project the EHT staff chose StormMaster Shake shingles from Atlas Roofing. These designer roof shingles resist high winds, harsh impact and extreme weather conditions. StormMaster Shake also features Scotchgard Protector to defend against those dark, dingy streaks that appear on roofs due to algae. With the algae threat removed, your home’s roof keeps the original color. The shingles are designed to resist cracking, splitting, warping and shrinking in both hot and cold weather climates for many years.

One option is to spray-paint all the roof penetrations to match.

One option is to spray-paint all the roof penetrations to match.

As always, check with the manufacturer and your local building inspector about code requirements for roof work in your area. Some manufacturers don’t warranty their product if installed over existing shingles, and a new layer should never be installed over any more than a single layer of old three-tab shingles. For this job to meet local code and the manufacturer’s warranty, we had to first cover the old shingles in 30-lb. felt paper before roofing installation. It’s also important to follow the manufacturer’s instructions to the letter regarding shingle layout and fastener placement.

First step is to apply 30lb. roofing felt. Apply the adhesive starter strip.

First step is to apply 30lb. roofing felt. Apply the adhesive starter strip.

Preparation

For a roof-over project, first replace all missing shingles. Split and securely nail any buckles, raised tabs or curled shingles.

My starter strip was too wide for the underlying shingle tabs, so I trimmed to fit.

My starter strip was too wide for the underlying shingle tabs, so I trimmed to fit.

To ensure performance and qualify for the warranty, make sure the attic ventilation complies with FHA Minimum Property Standards.

I applied Through the Roof roofing sealant above and below the starter strip.

I applied Through the Roof roofing sealant above and below the starter strip.

To maintain a Class A fire rating, I applied a layer of 30-lb. felt underlayment  over the old shingles, beginning at the rake and overlapping each succeeding course by roughly 4 inches, tacking it down with roofing nails.

Fastening

The StormMaster Shake shingles require 11- or 12-gauge corrosion-resistant roofing nails with 3/8-in. minimum head. The nails must be long enough to penetrate the roof deck 3/4 inch. If the deck is less than 3/4-in. thick, the nails should be long enough to penetrate fully and extend at least 1/8 inch through the roof deck. Keep in mind that a roof-over project requires nails that are long enough to pass through the extra layer of shingles. For this project I recommend a minimum nail length of 1-3/4 inch.

Chalk lines can help guide the layout.

Chalk lines can help guide the layout.