Choose and install asphalt shingles carefully when putting on new roofs or repairing old ones. This helps prevent water leaks from damaged or blown-off shingles in high winds, hurricanes, wildfires, or severe winter weather.  Typical Asphalt Roofing Shingle Sizes

Width: 13 1/4 inches (metric) or 12 inches (imperial)

Length: 40 inches (metric) or 36 inches (imperial)

Thickness: Approximately 1/8 inch; fiberglass shingles are thinner than tar paper shingles.

Components of Shingles

Framing: This includes roof trusses that support the roof's weight. The structure must be strong enough for the roofing material used, such as ceramic tiles or slate.

Insulation: Insulation is found in the attic to reduce heat loss. It’s placed on the attic floor or between rafters in a finished attic.

Ventilation: Essential for removing heat and moisture from the attic. Proper ventilation prevents damage to framing, insulation, and sheathing, and avoids mold and mildew.

Roof Deck: The material on top of the roof trusses, usually plywood.

Water Shield: A peel-and-stick layer that creates a waterproof barrier against ice and water buildup near the eaves.

Underlayment: Felt or fiberglass paper covering the roof deck. It’s water-resistant and helps prevent water leakage.

Shingle Starter Strips are installed at the eaves to prevent wind uplift. They can be purchased or made by cutting regular shingles.

Roofing Material: The visible layer of the roof is available in various materials like asphalt shingles, cedar shakes, tiles, metal sheets, or rubber for flat roofs.

Ridge Vents: Located at the roof’s peak, allowing warm, moist air to escape from the attic.

Flashing: Sheet metal used to prevent water penetration at seams where materials meet, such as along eaves (drip edge), chimneys (step flashing), skylights, and vents.

For New Construction

For new construction, you may install these roofing:

Seal the Roof Deck: Install a self-adhered membrane over the entire deck (use #15 felt as a bond break). Install 4-inch-wide roof deck flashing tape over panel seams and cover with #30 felt or synthetic underlayment. Install a two-layer #30 felt underlayment system.

Install Drip Edge: Place at eaves and rakes.

Install Flashing: At roof penetrations and roof-wall intersections, integrated with roofing and wall underlayment.

Install Shingles: Based on the local wind speed, use high-wind-rated shingles (consider impact-resistant and solar-reflective shingles).

Follow the Manufacturer’s Instructions

• Use 6 nails per shingle.
• Properly locate and drive nails (no staples).
• Use hot-dip galvanized or stainless steel fasteners near salt or brackish water.

Enhance Shingle Securement

Apply asphalt roof cement beneath shingles and starter strips along eaves, rakes, hips, ridges, and open valleys.

For Wildfire-Prone Areas

Choose Fire-Resistant Materials: Use Class A-rated materials like fiberglass-reinforced asphalt shingles, fiber-cement shingles, galvanized metal with gypsum, slate, or concrete/clay tiles with bird-stopping.

Design Considerations: Choose a simple roof design to reduce ember trapping.

For Cold Climates and High-Snow-Load Regions

Install Self-Adhering Membrane: Along roof eaves. Ensure proper air sealing, insulating, and ventilation of the attic to prevent ice dam formation.

How to Install Asphalt Shingles

Dekr Roofing simplifies things by covering the basic steps and the purpose of each roofing component. However, it’s not a replacement for hands-on training, and Dekr advises that only trained roofing professionals should do the work. 

Step 1: Prioritize Safety in Roofing Projects

The first step in any roofing project is safety. Working on a roof has fall risks and other safety concerns. Dekr Estimation advises using qualified professionals who are trained in roofing safety. Also, check local building codes to make sure the roof meets all requirements.

Step 2: How Shingles Work to Shed Water

Asphalt roofing shingles use gravity to move water away from the roof. When shingles and other roof parts are properly arranged and overlapped, the roof will effectively shed water. “To shingle” means to lay out or arrange things so they overlap. Let’s look at how this overlapping sequence works in roof construction.

Step 3: Deck Preparation

Before installing roofing materials, ensure the roof deck is smooth, well-fastened, dry, and free of gaps or holes. A clean, flat deck will help the new roof look smooth and flat.

Step 4: Starting with the Drip Edge

We start with the bottom layer of roofing components. Asphalt shingles are the top layer, but what’s underneath matters too. The first material installed is the drip edge. It creates a clean edge and protects the roof deck from water damage by preventing water from flowing back up.

Step 5: Adding Ice and Water Protection to Your Roof

In cold climates, your roof needs extra protection, just like you need boots in winter. An ice and water protector is a thin, self-adhering membrane installed over the drip edge. It helps prevent ice dams and is often required by local codes. The membrane should extend 1/4″-3/4″ over the eaves and up the roof at least 24″ from the wall. It should also cover any roof valleys. This protector seals around shingle fasteners, adding extra water-shedding protection.

Step 6: Installing Roof Underlayment

Next, install the roof underlayment, which can be asphalt-saturated felt or synthetic. Both types protect under the shingles. While asphalt shingles handle the main water-shedding, underlayment adds extra protection. Felt should be laid in horizontal rows, overlapping the eave ice and water protector by 4″ and the valley membrane by 6″. Dekr’s RoofGard-Cool Grey Synthetic Roof Underlayment provides extra protection for your roof.

Step 7: Flashing and Valley Installation for Leak Prevention

Roofs are most likely to leak where shingles are penetrated, interrupted, or meet walls, so these areas need flashing to direct water down the slope. For open valleys, line them with corrosion-resistant metal before installing shingles. Closed valleys are completed during shingle installation. Dekr recommends using open metal valleys for better performance. Before applying shingles, complete the underlayment and valley flashing with 28-gauge galvanized metal or similar material. Center a 36″ strip of ice and water protector in the valley, overlapping pieces by at least 6″, and secure the metal valley liner with nails at the edges, sealing overlaps with asphalt plastic cement. Snap chalk lines in the valley and lay shingles over the flashing, trimming them to the lines, nailing them 2″ back, and using asphalt plastic cement at the valley ends. Flash around plumbing stacks, vents, and where shingles meet walls or chimneys. Use ice and water protector membranes for skylights and other tricky areas, ensuring that flashing and shingles work together for complete protection.

Step 8: Installing Asphalt Shingles

Once the preparation beneath the shingles is complete, it’s time to shingle the roof. Start at the bottom and work your way up, overlapping each row. Begin with a course of starter shingles at the eaves. These can be purchased or cut from standard shingles. Starter shingles provide seal and water protection at shingle joints. Professional contractors often use starter strips along rake edges for a straight start and better wind resistance.

Follow the manufacturer's instructions for exposure, offset, and nail placement. Proper nail placement is cru important for wind resistance and warranty coverage. For closed valleys, shingles are laid across the valley, with each course extending at least 12″ into the valley. Trim shingles on the adjoining side to 2″ back from the valley centerline.

Step 9: Installing Ridge and Hip Caps

Once the field shingles are in place, you’re ready to install the hip and ridge caps. These caps cover the roof’s peak and hips to ensure water sheds correctly. For ridges, start at the end opposite the prevailing wind direction to enhance wind resistance. For hips, begin at the bottom and work up. Use longer nails for ridge caps to ensure they penetrate through the caps and the underlying shingles. Seal and cover the nail heads with asphalt roof cement to prevent leaks.