How To Lay Cedar Shingles: A Master Craftsman Guide To Architectural Installation

Laying cedar shingles requires precise spacing, careful flashing integration, and adherence to exposure and overlap standards to achieve a roof or siding assembly that lasts for decades. Mastery of this process depends on maintaining proper side-laps, selecting top-grade vertical-grain lumber, and allowing adequate ventilation beneath the shingles to prevent premature moisture decay.

Pre-Operation & Equipment Checklist

Successful installation of red or white cedar shingles demands an exacting approach to site preparation, material sorting, and tooling. Whether applied to a vertical wall or a sloping roof deck, cedar shingles interact dynamically with ambient humidity, swelling when wet and shrinking when dry. Accounting for these natural dimensional shifts dictates the tools you need and the layout standards you must follow.

• Essential Gear, Tools, and Materials:

  
  
  
  • Premium No. 1 Blue Label cedar shingles (radiata, western red, or northern white cedar, preferably clear, vertical-grain).
  • Pneumatic or palm nailer with stainless steel or hot-dipped galvanized ring-shank nails (minimum 3d size, 1-1/4 inches long for walls, longer for roofs).
  • Chalk line, blue or red chalk (avoid black permanent chalk that bleeds through wood).
  • Stainless steel stapler or hammer tacker for underlayment.
  • Plumb bob, spirit level, and framing square.
  • Utility knife with heavy-duty hook blades.
  • Wide-jaw shingle hatchet or specialized shingle laying gauge.
  • Non-corrosive flashing materials (copper, lead-coated copper, or heavy-gauge aluminum) for valleys, eaves, and penetrations.
  • Breathable breather-type underlayment (avoid non-porous asphalt felt that traps moisture beneath wall shingles).

• Mandatory Prerequisite Knowledge and Standards:

  
  
  
  • Familiarity with local building codes regarding fire ratings and minimum roof pitches (typically 4:12 pitch for standard shingle applications, though lower slopes require specialized multi-ply underlayment systems).
  • Understanding of the natural "double-start" course and the 1/4-inch spacing rule between individual shingles to allow for lateral expansion.

• Estimated Budget and Duration Benchmarks:

  
  
  
  • Material costs range from moderate to high depending on grade and species, generally calculated per "square" (an area that covers 100 square feet when applied at the recommended weather exposure).
  • Labor output averages 1.5 to 2.5 squares per installer per day, depending on architectural complexity, corners, and window/door trim details.

Step-by-Step Cedar Shingle Installation Workflow

Step 1: Surface Preparation and Underlayment Installation

Ensure the substrate is clean, dry, and structurally sound. For roof applications, install spaced sheathing (1x4 or 1x6 boards spaced on centers equal to the shingle exposure) or solid plywood sheathing covered with a breathable, UV-resistant breather membrane. For wall applications, install furring strips over a weather-resistive barrier to establish a continuous rain screen cavity, preventing capillary moisture movement from the sheathing into the back of the cedar. Snap a baseline horizontal chalk line along the bottom edge of the wall or roof to guide the critical first course.

Pro-Tip: Always install a starter course consisting of a double layer of shingles at the eave or base. This ensures proper water shedding and height transition for the subsequent courses.

Step 2: Setting the Double Starter Course

Align the bottom edge of your starter course shingles 1 to 1.5 inches below the framing line to create a drip edge over the fascia or foundation. Nail each starter shingle with two fasteners positioned approximately 3/4 inch in from each edge and 1 to 2 inches above the future exposure line. Drive nails flush, ensuring the heads do not crush the wood fibers or countersink deeply enough to split the grain. Maintain a 1/4-inch gap between adjacent starter shingles.

Warning: Never butt cedar shingles tightly against one another. Without the 1/4-inch expansion gap, wet weather will cause the shingles to buckle, split, or pop their fasteners.

Step 3: Laying Subsequent Courses and Maintaining Spacing

Work upward from the starter course, snapping chalk lines for every single course or every second course to maintain absolute horizontal alignment. Select shingles randomly from different bundles to blend natural color variations and grain densities evenly across the facade. Offset the vertical side-joints of each new course by at least 1-1/2 inches from the joints in the course immediately below, and never let side-joints line up with joints two courses apart (the "no-joint alignment in three consecutive courses" rule).

Step 4: Managing Openings, Corners, and Valleys

When encountering windows, doors, or outside corners, custom-rip shingles using a utility knife or fine-tooth handsaw. For outside wall corners, construct a woven corner or use pre-assembled corner boards, alternating overlapping shingles from left to right on successive courses. On roofs, weave closed valleys carefully or install W-type metal valley flashing, keeping fasteners at least 2 inches away from the center of the valley line to prevent water infiltration.

Comparative Specifications of Cedar Shingle Grades

Common Site Failures and Field Fixes

Even experienced installers occasionally encounter issues stemming from wood movement or fastening errors. Identifying these problems early prevents catastrophic moisture intrusion.

• Root Cause: Fastener staining and dark tannin bleeding around nail heads.

  
  
  
  • Actionable Fix: Remove standard steel fasteners immediately and replace them with Type 316 stainless steel ring-shank nails. Apply an oxalic acid wash to neutralize and lift the tannin stains before finishing.

• Root Cause: Cupping, warping, and splitting of wide shingles.

  
  
  
  • Actionable Fix: Shingles wider than 8 inches experience excessive internal stresses. Rip any wide shingles into narrower 4-to-6-inch segments prior to installation, and verify that the back side of the wall assembly features adequate ventilation space.

• Root Cause: Premature rot at the butt line due to ground splash-back.

  
  
  
  • Actionable Fix: Maintain a minimum clearance of 8 inches between the bottom edge of wall shingle courses and finished grade, mulch beds, or concrete flatwork. Install non-corrosive kick-out flashing where roofs intersect vertical walls.

Frequently Asked Questions

Do cedar shingles need to be treated or sealed after installation?

Cedar contains natural preservative oils (thujaplicins) that resist decay and insect infestation without chemical treatments. However, applying a transparent, breathable oil-based sealer or weathering stain can slow down UV graying and extend the aesthetic lifespan of the installation. Avoid film-forming polyurethane coatings, as they trap moisture and cause peeling.

What is the correct nail size and type for cedar shingles?

Always use ring-shank nails made of Type 316 stainless steel or hot-dipped zinc-coated galvanized steel. Standard electro-galvanized nails will react with the natural acids in cedar and rust rapidly, causing severe staining and loose shingles. Nails should be long enough to penetrate at least 3/4 inch into solid wood sheathing or framing.

How do you calculate how many bundles of shingles are needed for a project?

Coverage is measured in "squares," where one square equals 100 square feet of finished wall or roof surface. Premium No. 1 cedar shingles are typically packaged so that four bundles equal one square when installed at standard weather exposures. Always add a 10% waste factor to your total material calculation to account for cuts, trimming around openings, and imperfections.

Can cedar shingles be installed directly over old asphalt roof shingles?

While some building codes permit installing wall shingles over old siding if furring strips are used, laying cedar roof shingles directly over old asphalt shingles is generally discouraged. Old asphalt layers trap heat and moisture, accelerating the decay of the cedar from underneath. Stripping the roof down to the wooden deck allows for proper installation of breather underlayment and spaced sheathing.

Transform Your Exterior with Professional-Grade Cedar Craftsmanship

Start your cedar shingle project with confidence by sourcing high-grade vertical-grain materials and adhering strictly to proper fastening and spacing guidelines. Explore our library of advanced architectural tutorials for more expert techniques on flashing, framing, and long-term wood preservation.