Cedar Shake Installation Starts With Precise Spacing and Water Control
A successful cedar shake installation starts with a dry, solid deck, corrosion-resistant fasteners, correct shake spacing, and careful flashing. Install from the bottom up, use a double starter course at the eaves, keep side joints at least 1 1/2 inches apart from those in the course below, and leave room for natural wood movement.
For a roof, the basic sequence is:
- Install code-approved underlayment and flashing before the shakes.
- Set a doubled starter course with proper eave and rake overhang.
- Nail each shake without overdriving the fastener.
- Maintain the required keyway gap and stagger joints across every course.
- Add felt interlay between shake courses where the system requires it.
- Finish exposed cedar promptly with a compatible coating if a painted or stained look is planned.
Cedar is durable, beautiful, and naturally resistant to decay, but it is still wood. It expands and contracts with moisture. Small errors – tight keyways, aligned joints, exposed nails, weak flashing, or poor ventilation – can lead to cupping, leaks, and early wear. The details matter as much as the material.
I am Dustin Eatman, owner of James Kate Roofing & solar, with hands-on experience planning, inspecting, and managing cedar shake installation and other high-performance roofing systems across DFW. In the sections ahead, I will break down the installation details that help a cedar roof or sidewall look right and protect the property for the long term.
Essential cedar shake installation terms:
Pre-Installation Storage, Safety Precautions, and Deck Preparation
Before driving a single nail, jobsite preparation dictates the longevity of the entire assembly. Western Red Cedar and Alaskan Yellow Cedar arrive from the mill with specific moisture content profiles. If left directly on damp ground or raw concrete slabs, wood acts like a giant sponge. We always store bundles flat on pallets, elevated off the ground, inside a dry, well-ventilated, unheated staging area. If bundles must sit outdoors, keep them covered with a breathable tarp while placing a heavy vapor barrier beneath the pallets to block rising moisture. Using slip sheeting between pallet layers maintains balanced airflow so individual pieces acclimate evenly without cupping or warping.
Workplace safety is equally paramount. Cutting, trimming, and shaping cedar produces fine airborne wood dust. The International Agency for Research on Cancer (IARC) classifies hardwood and wood dust as a known nasal carcinogen. The natural aromatic thujaplicins and plicatic acid that give Western Red Cedar its rot resistance and rich fragrance can irritate respiratory tracts and trigger acute skin reactions. Installers should always wear NIOSH-approved N95 or P100 dust masks, wrap-around eye protection, and durable gloves when manipulating stock.
A reliable wood roof requires an unyielding, flat substrate. Solid plywood sheathing (minimum 15/32-inch CDX) or 7/16-inch OSB provides the baseline structural deck. For historic renovations or open-frame designs, spaced 1×4 or 1×6 boards nailed into rafters allow optimal back-ventilation.
Over solid decks, install an underlayment of No. 30 asphalt-saturated organic felt conforming to ASTM D226 Type II or ASTM D4869 Type IV. Non-breathable synthetic sheets and non-permeable underlayments can trap condensing vapor beneath the shakes, accelerating wet rot. When laying felt, provide minimum 2-inch horizontal laps and 6-inch vertical end laps. For comprehensive principles on underlayment anchoring and substrate alignment, review our guide on Mastering Roof Shingle Installation Tips And Tricks.
Step-by-Step Cedar Shake Installation Process for Roofs and Sidewalls
Proper installation requires disciplined geometric alignment. Wood shakes must never be treated like standard asphalt shingles; each piece is unique in grain, taper, and thickness.
- Calculate the Story Pole: Measure the rafter length or wall height. Lay out course intervals so exposure remains consistent from eave to ridge, aligning butt lines neatly with window heads and architectural trim lines.
- Install the Double Starter Course: At the bottom edge, fasten a full starter course of 15-inch starter shakes or trimmed full-length shakes directly to the deck. Project the starter butt 1 1/2 inches past the fascia board to allow water to drop cleanly into gutters, and overhang the gable/rake edges by roughly 1 inch. Fasten the face course directly over the starter course, staggering every side joint by at least 1 1/2 inches.
- Set the 18-Inch Felt Interlay (Roofs Only): After nailing each course of shakes, lay an 18-inch-wide strip of ASTM No. 30 organic felt across the field. Position the bottom edge of the felt interlay up from the shake butt at a distance equal to twice the weather exposure. For example, on a 24-inch shake with a 10-inch exposure, place the bottom edge of the felt strip exactly 20 inches above the butt. This positions the felt entirely above the exposed wood, acting as an internal baffle that channels any moisture driven between the keyways back over the outer face of the course below.
- Maintain Course Straightness: Use a chalk line snapped across the upper portion of the shakes, or rest shakes along a straight-edge wood ledger temporarily screwed to the roof deck. Always verify horizontal level every three to four courses.
For full technical specifications on slope transitions and Certi-label® standards, consult the Cedar Roof Installation Manual – Cedar Shake & Shingle Bureau.
Essential Fasteners and Nailing Guidelines for Cedar Shake Installation
The wrong fastener will destroy a cedar roof decades before the wood reaches its natural service limit. Cedar contains natural tannins that corrode standard steel and strip electro-galvanized coatings, causing dark black streaks and fastener pull-out.
- Fastener Metal Chemistry: All nails or staples must be hot-dipped zinc-coated galvanized steel meeting ASTM A153 Class D (minimum 1.0 oz/ft² coating weight), Type 304 stainless steel, or marine-grade Type 316 stainless steel. Electro-galvanized (EG) fasteners are strictly prohibited.
- Coastal Environments: If the structure sits within 15 miles of salt water, code mandates Type 316 stainless steel fasteners to resist airborne chloride corrosion.
- Fastener Length & Penetration: Nails must penetrate at least 3/4 inch into the sheathing or pass completely through solid wood decking. For dimensional lumber framing or sidewall studs, ensure fasteners penetrate at least 1/2 inch to 1 inch into solid wood. Ring-shank nails are strongly recommended in high-wind regions for maximum withdrawal strength.
- Nail Placement: Use exactly two nails per shake for pieces up to 10 inches wide. Position nails 3/4 inch inward from each outer edge and 1 1/2 inches above the predetermined exposure line (or 1 inch above the butt line of the succeeding course for concealed nailing).
- Extra Nailing for Wide Shakes: When installing Western Red Cedar pieces wider than 10 inches, drive two additional nails centered approximately 1 inch apart near the midline to prevent cross-grain splitting and cupping.
- Drive Depth: Drive fastener heads flush with the wood surface. Never overdrive the nailhead into the wood fibers, as crushed wood creates pockets that hold moisture and cause premature localized decay.
Precision Keyway Spacing and Joint Staggering
As relative humidity swings between sweltering Texas summers and wet winter fronts, cedar breathes. For every 4 inches of dry Western Red Cedar width, the wood expands roughly 1/8 inch across its grain when saturated. If shakes are nailed edge-to-edge without a thermal expansion gap (keyway), the swelling wood will buckle, pinch, and crack off fastener heads.
| Cedar Grade & Product Type | Keyway Spacing (Sidewall) | Keyway Spacing (Roof Application) |
|---|---|---|
| Number 1 Grade Western Red Cedar Shakes | 3/8″ to 1/2″ | 3/8″ to 5/8″ |
| Number 1 Grade Western Red Cedar Shingles | 1/8″ to 1/4″ | 1/4″ to 3/8″ |
| Number 1 Grade Yellow Cedar Shingles | 3/16″ to 5/16″ | 1/4″ to 3/8″ |
| Number 2 Grade Rebutted & Rejointed (R&R) | 1/4″ to 3/8″ | 1/4″ to 3/8″ |
| Number 3 Grade Shingles | 1/2″ minimum | Not Recommended for Prime Roofs |
Never allow vertical side joints to line up in adjacent courses. Maintain a minimum side lap offset of 1 1/2 inches between joints in consecutive courses. Furthermore, ensure that no joints in any three consecutive courses align vertically. Checking spacing with a handheld gauge ensures flawless visual rhythm and absolute weather tightness.
Flashing, Corners, and Wall Penetrations Integration
Every roof penetration, chimney, dormer, and wall intersection demands rigid flashing integration:
- Valley Assemblies: Install minimum 24-gauge pre-finished sheet metal, copper, or stainless steel center-crimped “W” valley flashing over a full layer of self-adhering modified bitumen membrane. Keep shake butts trimmed back along a straight chalk line to leave an open valley trough at least 6 inches wide at the top, tapering wider toward the eaves.
- Sidewall & Corner Boards: When butting shakes against corner boards, window casing, or exterior door trim, the trim material must extend outward at least 1 inch from the sheathing to accommodate the full profile depth of the cedar. Leave a 1/8-inch gap between the shake edge and the casing, and seal this perimeter with a high-grade, non-hardening sealant.
- Woven Outside Corners: For a classic craftsman finish without corner boards, weave the outside corners. Shingle both adjoining wall faces simultaneously. Lap the edge of the corner shake on Wall A over Wall B, plane it flush with a block plane, and on the next course, reverse the lap by overlapping Wall B over Wall A.
- Ground and Flashing Clearance: Keep the bottom edge of the starter course at least 1/2 inch clear of horizontal flashings, hardscape surfaces, or lower roof decks to prevent the wood end-grain from wicking pooling water.
Detailed wall intersection patterns are documented inside the CSSB EXTERIOR & INTERIOR architectural guide.
Advanced Applications: Single vs. Double Coursing and Treated Cedar
When installing cedar shakes on exterior sidewalls, craftsmen choose between single coursing and double coursing methods.
- Single Coursing: Shakes are applied one layer per exposure line over No. 30 felt. This system is fast, economical, and delivers classic architectural texture with standard shadow lines.
- Double Coursing: A layer of inexpensive Number 3 or 4 grade undercourse shingles is applied first, and a Number 1 grade face shake is nailed directly over it, completely concealing the undercourse while dropping roughly 1/2 inch lower at the butt. Double coursing allows dramatically wider weather exposures (up to 12 inches on 16-inch shingles and 14 inches on 18-inch shingles), delivers rich, deep shadow relief, and creates an exceptionally durable thermal wall envelope. Furr out the bottom wall course with a 3/8-inch by 1-inch wood strip to maintain uniform angle cant throughout.
- Fastening Double Courses: In double-course wall assemblies, face-nail the outer exposed shake with two 5d or 6d small-head corrosion-resistant nails driven 2 inches above the butt line and 3/4 inch in from each side edge.
For property owners seeking the organic visual appeal of wood with alternative low-maintenance performance, explore how you can Upgrade Your Curb Appeal With Synthetic Cedar Shake Siding.
Sidewall vs. Roof Differences in Cedar Shake Installation
While sidewalls shed water quickly through gravity, roofs must contend with slow drainage, ponding risks, and wind-driven rain. Consequently, the mechanical rules diverge:
- Roof Pitch Limitations: Cedar shakes demand a minimum roof pitch of 4:12. Slopes between 3:12 and 4:12 require an engineered, fully waterproof continuous bituminous membrane underlayment system overlaid with a wood lattice assembly.
- Weather Exposure Allowances: Sidewalls tolerate significantly higher exposures because they shed moisture rapidly. On roofs, maximum weather exposure for 18-inch handsplit shakes is 7 1/2 inches, and for 24-inch shakes it is 10 inches. On sidewalls, single-course 18-inch Number 1 shakes can be exposed up to 8 1/2 inches, and double-coursed up to 14 inches.
- Felt Interlays: Felt interlays are strictly utilized on shake roofs. Felt interlay is never installed between courses of sawn cedar shingles on roofs, nor is it used between courses on sidewall shingle installations. Sawn shingles lie flat and require uninhibited breathability across their underside to dry evenly.
Post-Installation Finishing, Extractive Bleeding Prevention, and Maintenance
Western Red Cedar contains water-soluble extractives (tannins). When unprotected raw wood meets excessive moisture before curing, tannins migrate to the surface and react with atmospheric oxygen, creating unsightly dark brown and black streaks called extractive bleeding.
- Priming and Painting: If painting cedar shakes, always apply a high-solids, 100% oil-based stain-blocking primer to all sides (including cut edges) before installation. Follow the primer with two topcoats of premium exterior acrylic latex paint. Acrylic paint forms a flexible, vapor-permeable membrane that expands and contracts with the wood without blistering.
- Staining and Weathering: To highlight natural grain, apply semi-transparent or solid-color penetrating oil-based exterior stains. For an authentic Cape Cod or vintage rustic aesthetic, apply commercial accelerated weathering agents, which convert the wood’s outer cell layers to a uniform driftwood silver-gray while protecting the core against uneven ultraviolet breakdown.
- Deck Ventilation Integrity: Never install impermeable spray foam insulation directly against the underside of a cedar shake roof deck. Spray foam encapsulates the sheathing, traps moisture inside the wood cellular structure, prevents normal drying cycles, and will induce rapid deck rot within three to five years. Ensure continuous, balanced soffit-to-ridge passive ventilation.
For long-term care plans to preserve system performance year after year, refer to our comprehensive Roof Maintenance Guide 2026.
Frequently Asked Questions About Cedar Shake Installation
What is the minimum offset required between cedar shake joints across adjacent courses?
Every joint between shakes must be offset by a minimum of 1 1/2 inches from the joints in the course directly below it. Additionally, ensure that no joints align vertically across any three consecutive courses. Staggering joints prevents water entering a keyway gap from finding a direct seam into the underlayment.
Which fasteners must be used when installing cedar shakes within 15 miles of salt water?
Building codes and CSSB standards mandate the use of Type 316 stainless steel nails or staples for all installations located within 15 miles of a saltwater coastline. Marine air contains airborne chlorides that break down ordinary galvanized coatings, causing rapid structural fastener failure.
Why is felt interlay placed between shake courses on roofs but omitted from shingle installations?
Because handsplit and tapersawn shakes have rough, irregular, split surfaces, they do not lie perfectly flat against each other. Wind can drive rain or fine snow beneath their uneven butts. The 18-inch felt interlay acts as an internal watershed baffle. Conversely, sawn cedar shingles are smooth and tapered; installing felt between shingle layers traps moisture between the tightly stacked flat surfaces, leading to wood rot.
Conclusion
A master-crafted cedar shake roof or sidewall represents the pinnacle of residential exterior artistry. Achieving generational performance requires absolute adherence to keyway spacing, disciplined joint offsets, non-corrosive fasteners, and balanced deck ventilation. When executed with precision, a genuine cedar system provides unmatched wind resistance, natural thermal insulation, and timeless beauty.
At James Kate Roofing & solar, our family-owned team brings honest craftsmanship, deep technical expertise, and Biblical integrity to every project we undertake across the DFW Metroplex. Whether you need specialized cedar installation, comprehensive storm recovery, or expert roof installation services in Grand Prairie, TX, we stand behind our workmanship with up to a 25-year warranty. Contact us today to schedule your professional property assessment.
Dustin Eatman is a seasoned roofing professional with deep, hands-on expertise that spans residential and commercial roofing, insurance solar, and long-term roof asset management. As the owner of James Kate Roofing & solar in the Dallas–Fort Worth metroplex, he’s built a reputation for diagnosing roof systems accurately, communicating clearly, and executing projects with a high standard of workmanship and documentation. Dustin understands the technical details that make roofs perform—proper underlayment selection, slope and drainage considerations, ventilation strategy, flashing and penetration detailing, and manufacturer-specific installation requirements—because he’s worked through the real-world challenges that cause leaks, premature wear, and warranty issues. He’s equally fluent in the operational side of roofing: jobsite planning, quality control, safety, material ordering, crew coordination, and customer experience from inspection to closeout. In insurance-related projects, Dustin brings practical knowledge of claim workflows, adjuster meetings, scope alignment, supplements, and the importance of photo evidence and thorough records, helping property owners navigate stressful situations with confidence. For commercial clients—especially property and facility managers—he emphasizes proactive maintenance and targeted repairs that reduce disruption, extend roof life, and prevent expensive interior damage. Dustin also stays focused on doing things the right way: educating customers on realistic options, setting expectations, and prioritizing solutions that hold up over time rather than quick fixes. That blend of technical skill, field experience, process discipline, and owner-level accountability is what makes Dustin Eatman a trusted expert in the roofing industry.