CSSB Trade Show & AGM 2026
October
14-15, 2026
Chicago, IL
Preventing Buckling and Warping in Cedar Siding
Press Release |
September 3, 2026
Buckling and warping in cedar siding are among the most preventable failures in wood cladding installation, yet they remain a persistent source of callbacks for contractors who skip the fundamentals. At the Cedar Shake & Shingle Bureau, we have guided the industry since 1915, and the causes behind these deformation failures haven’t changed: improper moisture management, inadequate fastening, and material handling that ignores cedar’s natural behaviour. Understanding how to prevent buckling and warping in cedar siding starts before the first course is ever nailed.
How Moisture Drives Deformation
Cedar is hygroscopic. It absorbs and releases moisture in response to its environment, and dimensional movement is a natural consequence of that cycle. Problems begin when that movement is restricted or when moisture is introduced unevenly across a siding profile.
Key moisture-related failure points include:
- Installing at incorrect moisture content: Cedar siding should be installed at a moisture content appropriate for the local climate. Material delivered wet and nailed tight will buckle as it dries and tries to shrink.
- Omitting back-priming: Sealing only the face of a siding board while leaving the back exposed creates a moisture differential. The uncoated side absorbs and releases at a different rate, generating internal stress that leads to cupping and warping over time.
- Blocking drainage and ventilation: A rainscreen gap behind the cladding allows moisture to drain and the back face to dry. Without it, water trapped against the sheathing has nowhere to go.
Proper Storage and Acclimation on the Job Site
Material handling before installation is where many deformation problems originate. Cedar delivered to a site must be stored correctly, or the moisture content at time of installation will be inconsistent.
Storage Requirements
Store bundles off the ground on stickers to allow air circulation on all sides. Keep material covered but not sealed, since vapour needs to move. Direct sun and heat sources should be avoided, as both dry surface layers unevenly and set up the kind of moisture differential that causes problems once boards are fastened.
Acclimation
Allow cedar to acclimate to local ambient conditions before installation. In high-humidity climates, this reduces the risk of boards tightening against each other after fastening. In arid regions, it prevents the excessive shrinkage that opens face cracks and creates gaps at the joints.
Fastening Practices That Allow for Movement
Cedar siding must be fastened in a way that permits natural wood movement without restraining it to the point of failure. Overdriven fasteners, incorrect nail placement, and face nailing through multiple layers are common contributors to buckling.
Follow these fastening principles:
- Use the correct nail length and material: Hot-dipped galvanized or stainless steel nails are required to resist the corrosive extractives in cedar. Electrogalvanized fasteners will fail prematurely and stain the face.
- Nail placement matters: For bevel siding, nails should clear the top of the underlying course rather than penetrating through it. Through-nailing two courses ties them together and prevents independent movement.
- Do not face-nail near edges: Fasteners driven close to board ends split the grain and concentrate stress at exactly the point where checking is most likely to occur.
- Avoid overdriving: A fastener countersunk too deep crushes wood fibres and reduces holding power, which allows boards to move laterally with seasonal cycling.
Finishing and Coating Considerations
Finish application has a direct bearing on long-term dimensional stability. Cedar siding left unfinished, or finished only on the face, is significantly more vulnerable to moisture-driven movement.
Priming All Surfaces
Back-prime every board before installation. This is not a recommended best practice; it is a baseline requirement for genuine performance. All four sides, both ends included, should receive a coat of quality primer to equalize the rate of moisture exchange across the full profile.
Finish Selection
Penetrating finishes that allow the wood to breathe typically outperform film-forming coatings in regions with significant seasonal humidity swings. Film-building finishes that trap moisture beneath the surface can accelerate the very deformation they are meant to prevent.
Installation Detailing That Supports Long-Term Performance
Beyond fasteners and finish, the installation details that govern water management are equally critical.
- Maintain minimum clearance above grade, roofing, and horizontal surfaces to prevent wicking.
- Flash all horizontal joints and penetrations correctly to redirect water away from end grain.
- Ensure that the weather-resistive barrier beneath the cladding is properly lapped and integrated with window and door flashing.
End grain is the most moisture-vulnerable part of any cedar board. It absorbs water faster than face grain, and any installation detail that leaves end grain exposed or in contact with a water-collection point will eventually produce movement failures.
True Craftsmanship Starts With the Right Guidance
Buckling and warping in cedar siding are not wood failures. They are installation failures. Address moisture content before the first course, fasten correctly to allow seasonal movement, back-prime every board, and build in the drainage and ventilation details that cedar-clad assemblies require. These aren’t workarounds; they are the standard of true craftsmanship that has defined quality cedar installation for over a century. For technical questions about installation best practices, contact us directly through the contact form on our website.
Buckling and warping in cedar siding are among the most preventable failures in wood cladding installation, yet they remain a persistent source of callbacks for contractors who skip the fundamentals. At the Cedar Shake & Shingle Bureau, we have guided the industry since 1915, and the causes behind these deformation failures haven’t changed: improper moisture management, inadequate fastening, and material handling that ignores cedar’s natural behaviour. Understanding how to prevent buckling and warping in cedar siding starts before the first course is ever nailed.
How Moisture Drives Deformation
Cedar is hygroscopic. It absorbs and releases moisture in response to its environment, and dimensional movement is a natural consequence of that cycle. Problems begin when that movement is restricted or when moisture is introduced unevenly across a siding profile.
Key moisture-related failure points include:
- Installing at incorrect moisture content: Cedar siding should be installed at a moisture content appropriate for the local climate. Material delivered wet and nailed tight will buckle as it dries and tries to shrink.
- Omitting back-priming: Sealing only the face of a siding board while leaving the back exposed creates a moisture differential. The uncoated side absorbs and releases at a different rate, generating internal stress that leads to cupping and warping over time.
- Blocking drainage and ventilation: A rainscreen gap behind the cladding allows moisture to drain and the back face to dry. Without it, water trapped against the sheathing has nowhere to go.
Proper Storage and Acclimation on the Job Site
Material handling before installation is where many deformation problems originate. Cedar delivered to a site must be stored correctly, or the moisture content at time of installation will be inconsistent.
Storage Requirements
Store bundles off the ground on stickers to allow air circulation on all sides. Keep material covered but not sealed, since vapour needs to move. Direct sun and heat sources should be avoided, as both dry surface layers unevenly and set up the kind of moisture differential that causes problems once boards are fastened.
Acclimation
Allow cedar to acclimate to local ambient conditions before installation. In high-humidity climates, this reduces the risk of boards tightening against each other after fastening. In arid regions, it prevents the excessive shrinkage that opens face cracks and creates gaps at the joints.
Fastening Practices That Allow for Movement
Cedar siding must be fastened in a way that permits natural wood movement without restraining it to the point of failure. Overdriven fasteners, incorrect nail placement, and face nailing through multiple layers are common contributors to buckling.
Follow these fastening principles:
- Use the correct nail length and material: Hot-dipped galvanized or stainless steel nails are required to resist the corrosive extractives in cedar. Electrogalvanized fasteners will fail prematurely and stain the face.
- Nail placement matters: For bevel siding, nails should clear the top of the underlying course rather than penetrating through it. Through-nailing two courses ties them together and prevents independent movement.
- Do not face-nail near edges: Fasteners driven close to board ends split the grain and concentrate stress at exactly the point where checking is most likely to occur.
- Avoid overdriving: A fastener countersunk too deep crushes wood fibres and reduces holding power, which allows boards to move laterally with seasonal cycling.
Finishing and Coating Considerations
Finish application has a direct bearing on long-term dimensional stability. Cedar siding left unfinished, or finished only on the face, is significantly more vulnerable to moisture-driven movement.
Priming All Surfaces
Back-prime every board before installation. This is not a recommended best practice; it is a baseline requirement for genuine performance. All four sides, both ends included, should receive a coat of quality primer to equalize the rate of moisture exchange across the full profile.
Finish Selection
Penetrating finishes that allow the wood to breathe typically outperform film-forming coatings in regions with significant seasonal humidity swings. Film-building finishes that trap moisture beneath the surface can accelerate the very deformation they are meant to prevent.
Installation Detailing That Supports Long-Term Performance
Beyond fasteners and finish, the installation details that govern water management are equally critical.
- Maintain minimum clearance above grade, roofing, and horizontal surfaces to prevent wicking.
- Flash all horizontal joints and penetrations correctly to redirect water away from end grain.
- Ensure that the weather-resistive barrier beneath the cladding is properly lapped and integrated with window and door flashing.
End grain is the most moisture-vulnerable part of any cedar board. It absorbs water faster than face grain, and any installation detail that leaves end grain exposed or in contact with a water-collection point will eventually produce movement failures.
True Craftsmanship Starts With the Right Guidance
Buckling and warping in cedar siding are not wood failures. They are installation failures. Address moisture content before the first course, fasten correctly to allow seasonal movement, back-prime every board, and build in the drainage and ventilation details that cedar-clad assemblies require. These aren’t workarounds; they are the standard of true craftsmanship that has defined quality cedar installation for over a century. For technical questions about installation best practices, contact us directly through the contact form on our website.
