Shingle thatch is a distinctive and time-honored roofing technique that uses cedar shingles to recreate the sculptural texture and organic character of a reed-thatched roof. This craft emerged in the early 1900s and reached its peak popularity during the 1920s, when homeowners and builders sought to combine the romantic appearance of European thatch with the durability and availability of wood shingles. By steam-bending shingles along eaves and gables, curving course lines, and varying shingle exposures, craftsmen achieved a strikingly natural look. Understanding the history, materials, and methods behind shingle thatch is valuable for anyone restoring a period property or designing a new home with old-world character. For a comparison with other wood roof options, read our guide to fire treating cedar shakes.
The History and Origins of Shingle Thatch
Rise of a Distinctive Craft
In the early 1900s, a new shingling style came into fashion across North America. Known variously as shingle thatch, cottage thatch, and thatch-effect, this embellishment was designed to recreate the curved lines and varied textures of traditional reed-thatched roofs using readily available cedar shingles. By bending shingles around eaves and gables and by curving course lines while changing exposures, skilled roofers simulated the look of real thatch with remarkable fidelity.
The Creo-Dipt Company and Commercial Production
Shingle thatch became so popular in the 1920s that the Creo-Dipt Company of North Tonawanda, New York, began manufacturing prebent and precut shingles specifically for thatch-effect roofs. Architects and builders were encouraged to send their floor plans to Creo-Dipt, whose engineers would draw up appropriate roof-framing plans at no charge. The company also prestained their shingles using creosote as a preservative, offering five different shades matched to various hues of weathered thatch. Smaller competitors emerged in different parts of the country, which explains why shingle-thatch roofs turn up in many regions.
Enduring Examples
One of the most beautiful surviving examples is a large house built in 1921 in Sioux Falls, South Dakota. Many of these historic roofs feature eyebrow dormers, with shingle courses undulating gracefully over curved framing. Some examples even include curved ventilation windows in attic and garage roofs. Many of these original shingle-thatch roofs are now beginning to wear out, prompting a resurgence of interest in this nearly forgotten craft.
Structural Design and Framing Requirements
Roof Pitch and Geometry
Most historic shingle-thatch roofs were pitched to 12-in-12 or steeper. This steep pitch is essential for two reasons. First, it shows off the wave coursing to full visual effect. Second, steeper pitches make the bends in shingles at the eaves less severe, which reduces breakage during installation. Any shallower than 12-in-12, and the craftsmanship becomes difficult to appreciate from the ground.
Curved Framing Members
The visual magic of shingle thatch is only half the story. Hidden beneath the shingles is a carefully engineered system of curved framing members. The key structural elements include:
- Curved rafters that establish the undulating roof profile at valleys and ridges
- 1x lumber and lath strips bent to form the curved nailing surface for the shingles
- Curved valleys and rounded-over eaves that transition smoothly between roof planes
- Rounded rake (gable-end) rafters that complete the thatch effect at roof edges
Structural Load Considerations
Because shingle thatch uses much shorter shingle exposures than conventional roofing, the finished roof is significantly heavier. Here is a comparison of weight and material requirements:
| Property | Shingle Thatch Roof | Conventional Shingle Roof |
|---|---|---|
| Typical shingle exposure | 2.5 to 3 inches | 5 inches |
| Weight per square (100 sq ft) | Approximately 325 lb | Approximately 200 lb |
| Shingle grade | 16-inch perfection-grade | 16 to 18-inch standard grade |
| Material type | Western red cedar | Western red cedar or asphalt |
| Framing requirement | Reinforced rafters | Standard rafter spacing |
The additional weight means rafters must be sized accordingly. A structural engineer should evaluate existing roofs before converting to shingle thatch, and new construction should account for the heavier dead load from the outset. For more on modern alternatives, see our comparison of asphalt shingle roofing materials and installation.
Materials and Preparation
Cedar Shingle Selection
Shingle thatch relies exclusively on high-quality western red cedar. The recommended specifications are:
- Length: 16-inch shingles provide the right balance of flexibility and coverage
- Grade: Perfection-grade (also called clear grade) ensures minimal knots and defects that could cause breakage during bending
- Species: Western red cedar offers natural decay resistance and excellent bending characteristics when steamed
- Moisture content: Shingles should be at the proper moisture level for bending, typically above fiber saturation point
Steam Bending Process
The defining feature of shingle thatch is the use of steam-bent shingles at roof edges. The process follows these steps:
- Shingles are placed in a steam box or exposed to live steam for 15 to 30 minutes until pliable
- Each shingle is removed and immediately bent over a curved form or jig to the desired radius
- Bent shingles are clamped or weighted and allowed to dry in position, which sets the curve
- Once dry, the shingles retain their curvature and can be nailed in place along eaves, rakes, and valleys
Steam bending requires practice and patience. Over-steaming can make the wood too soft and prone to crushing; under-steaming leads to breakage. The technique works best with clear, straight-grained cedar that has no pre-existing cracks.
Additional Materials
Beyond the shingles themselves, a shingle-thatch roof requires specialized materials for the curved substrate:
- Curved nailing strips cut from 1x lumber on site to match the roof profile
- Waterproof underlayment rated for steep-slope applications
- Hot-dipped galvanized or stainless steel nails for corrosion resistance
- Flexible flashing materials for curved valleys and penetrations
Installation Techniques and Best Practices
Wave Coursing Method
The hallmark of shingle thatch is wave coursing, where shingle courses are laid in gently undulating lines rather than straight horizontal rows. The technique involves:
- Snapping curved chalk lines at regular intervals across the roof deck
- Adjusting shingle exposure course by course to follow the curved lines
- Varying the exposure between 2.5 and 3 inches, compared to the 5-inch standard for conventional shingling
- Maintaining consistent visual density while following the curved layout
This method uses substantially more shingles than straight coursing, which contributes to both the heavier roof weight and the rich, textured appearance.
Edge and Valley Treatment
The most visible elements of a shingle-thatch roof are the rounded eaves, rakes, and valleys. These areas require careful attention:
- Eaves: Steam-bent shingles extend beyond the fascia and are curved downward to mimic the rounded edge of a thatched roof
- Rakes (gable ends): Bent shingles wrap around the gable edge, creating a soft, rounded profile instead of a sharp corner
- Valleys: Curved framing creates a smooth transition between roof planes, with shingles woven across the valley line
- Dormers: Eyebrow dormers are framed with curved rafters, and shingle courses undulate gracefully over them
Ventilation and Weather Protection
Proper ventilation is critical under a shingle-thatch roof because the short exposures and dense shingle coverage can trap moisture. Best practices include:
- Installing ridge vents sized for the additional roof mass
- Using breathable underlayment that allows vapor transmission
- Maintaining continuous soffit ventilation at the eaves
- Avoiding ice dam formation with proper insulation and air sealing at the attic floor
These measures ensure the cedar shingles dry effectively after rain, extending the roof life to 30 years or more with proper maintenance.
Maintenance and Longevity
A well-built shingle-thatch roof can last several decades, but it requires periodic attention. Annual inspections should check for loose or cracked shingles, particularly at bent areas where stress is highest. Treated wood still benefits from a UV-protective stain every 5 to 8 years. Moss and debris should be removed gently to avoid disturbing the curved courses. When repairs are needed, matching the shingle type and achieving the correct bend profile is essential for maintaining the visual continuity of the roof. For a broader overview of roof covering options, see our complete guide to residential roofing materials.
Conclusion
Shingle thatch represents a remarkable chapter in American residential roofing, blending the artistry of traditional thatch with the practicality of cedar shingles. From the steam-bent edges to the wave-coursed fields, every element of this technique requires skill and careful planning. Whether you are restoring a historic property built in the 1920s or designing a new home inspired by this timeless craft, understanding the structural requirements, material specifications, and installation methods is essential to achieving an authentic result. The resurgence of interest in shingle thatch is well deserved, and preserving this knowledge helps keep a beautiful and durable roofing tradition alive. For inspiration on the architectural style that often accompanies this roof type, browse our gallery of stately shingle style homes.