A Comprehensive Guide to Installing Cedar Shingles

Installing cedar shingles is a time-honored method for creating a durable, aesthetically pleasing, and natural-looking roof or exterior wall. This classic building material offers excellent insulation properties, natural resistance to decay and insects, and a unique character that improves with age. However, a successful installation requires careful planning, the right tools, and a meticulous approach to ensure longevity and weather resistance. This guide will walk you through the entire process, from preparation to the final brush stroke.

Before you begin the physical work of installing cedar shingles, thorough preparation is the most critical step. First, check your local building codes to understand any specific requirements for roofing materials, especially concerning fire ratings. Cedar shingles must often be treated with a fire-retardant solution in many regions. Next, calculate the amount of material you will need. Shingles are sold in bundles, and coverage is measured in “squares,” with one square equaling 100 square feet. Always add a waste factor of 10-15% to your total order to account for cutting and mistakes.

Gather all the necessary tools and materials. You will need a hammer, a utility knife with extra blades, a chalk line, a tape measure, and a ladder. For safety, a roof harness is non-negotiable. The key materials include: cedar shingles, roofing felt (typically 30-pound), galvanized roofing nails (often 3d or 4d ring-shank nails with a 7/8-inch head), and 1×3 or 1×4 pine furring strips for walls. For a roof, you will also need ridge cap shingles, drip edge flashing, and valley flashing if your roof has valleys.

The foundation of a good shingle job is a solid underlayment. For a roof, start by installing a drip edge along the eaves. Then, roll out your roofing felt, starting from the bottom edge and overlapping horizontal rows by at least 2 inches. Staple it securely to the roof deck. For walls, you may apply a weather-resistant barrier like house wrap directly over the sheathing. On both roofs and walls, this underlayment acts as a secondary barrier against wind-driven rain.

The process of installing the shingles themselves is a methodical one. The core principle is to ensure that no joint between shingles in one course aligns with a joint in the course above or below. This is achieved by staggering the shingles.

1. Starter Course: For roofs, a double starter course is often used. The first course is installed upside down and backwards to create a level base and ensure the first regular course has the proper exposure. For walls, a starter strip or a pressure-treated board is used at the bottom to provide a slight angle outwards for water runoff.
2. Layout and Snapping Lines: Use your chalk line to snap horizontal lines across the entire surface at intervals equal to the desired exposure. Standard exposure for roofs is between 4 and 5 inches, while for walls it is usually 7 to 10 inches, depending on the shingle size and local weather conditions. These lines are essential for keeping your courses straight.
3. Nailing: Place each shingle and secure it with two nails, positioned about 3/4 inch to 1 inch from each edge and about 1 inch above the exposure line. This ensures the nail is completely covered by the next course. Do not overdrive the nails; the head should be flush with the surface of the shingle without crushing the wood.
4. Spacing: Leave a small gap, approximately 1/8 to 1/4 inch, between adjacent shingles to allow for natural expansion when the wood absorbs moisture.
5. Staggering Joints: As you move up each course, offset the joints by at least 1 1/2 inches from the joints in the course below. Many professionals recommend a stagger of half the shingle’s width.
6. Cutting and Fitting: Use a sharp utility knife to score and snap shingles to fit around obstacles like vents, pipes, and windows. For complex cuts, a pair of snips or a fine-toothed saw may be necessary.

Flashing is what keeps water from leaking into your structure at vulnerable points. Key areas that require flashing include: roof valleys, where two roof planes meet; the intersection of the roof with a wall or chimney; and around all protrusions like vent pipes. Use corrosion-resistant metal flashing (galvanized steel, aluminum, or copper) and integrate it carefully with the shingle courses, ensuring each layer overlaps the flashing to shed water downward.

Once all the field shingles are installed, you will need to finish the ridges and hips. For a roof, this is done with pre-made ridge cap shingles or by cutting and bending standard shingles. They are installed in an overlapping manner, starting from one end and working toward the other, with each cap shingle nailed on both sides. The final shingle is often bedded in a sealant for a watertight finish.

While unfinished cedar will eventually weather to a beautiful silvery-gray patina, applying a stain or sealant can enhance its durability and control its color. If you choose to finish them, use a brush or sprayer to apply a high-quality, penetrating oil-based stain or clear water repellent. This should be done after installation is complete and the wood has had a chance to dry out, typically waiting for a few weeks of dry weather. Reapply finishes as recommended by the manufacturer to maintain protection.

• Buckling or Curling: This is often caused by insufficient nailing or failing to leave expansion gaps. It can also occur if shingles were installed while too wet or too dry.
• Leaks at Flashing: The most common source of leaks is improperly installed flashing. Take your time here and ensure all overlaps are correct and facing downward.
• Inconsistent Exposure: Relying on the previous course of shingles as a guide, rather than your snapped chalk lines, can lead to a wavy, uneven appearance. Use your lines for every course.
• Splitting Shingles: Nailing too close to the edge or using the wrong type of nail can cause the cedar to split. Always use sharp, galvanized nails.

Installing cedar shingles is a rewarding project that significantly enhances the beauty and value of a home. While it demands patience and attention to detail, the result is a long-lasting, natural exterior that stands out for its quality and craftsmanship. By following these steps—meticulous preparation, careful layout, proper nailing, and flawless flashing—you can ensure your cedar shingle installation will protect and beautify your home for decades to come.