Cedar siding is a popular choice for residential and commercial construction due to its natural beauty, durability, and resistance to decay. However, to ensure long-term performance and aesthetic appeal, proper installation is essential. This article provides a detailed overview of cedar siding installation, based on guidelines from official documentation and technical specifications from reputable sources. It covers key aspects such as material selection, wall construction, fastening techniques, flashing, and sealing requirements. The goal is to equip builders, contractors, and DIY users with accurate, actionable information for successful cedar siding projects.
Key Considerations for Cedar Siding Installation
Before beginning the installation process, it is important to understand the specific requirements for cedar siding. Western Red Cedar, the species most commonly used for siding, has natural preservatives that make it resistant to insects and decay. However, to maintain its integrity and appearance, cedar must be installed with proper spacing, fastening, and sealing. The following sections break down the essential components of a cedar siding installation.
Pre-Installation Preparation
Wall Construction and Framing
Cedar siding must be installed on a properly constructed wall frame. The wall structure should support the siding and allow for proper ventilation and drainage. For stud walls, cedar siding can be applied directly to studs or over sheathing. When installing over sheathing, it is important to ensure that the sheathing is compatible with cedar and does not trap moisture.
According to the documentation, cedar siding should be nailed into studs at intervals of 24 inches (61 cm) when installed over wood-based sheathing and 16 inches (41 cm) when installed without sheathing. For vertical installations, horizontal blocking or furring strips may be required, depending on the wall construction. It is always recommended to check local building codes for specific requirements.
Masonry walls require furring strips to support cedar siding. The furring strips must allow for 1.5 inches (38 mm) of nail penetration into the masonry. This ensures secure fastening and prevents issues such as warping or loosening over time.
Flashing and Drainage
Flashing is a critical component of any siding installation, as it prevents water infiltration and directs moisture away from the building. Flashing should be installed around all wall penetrations, including windows, doors, bandboards, and water tables. The flashing must slope downward to allow water to drain away from the wall. Siding or trim should be installed at least ¼ inch above the flashing ledge to prevent water from seeping into the wall cavity.
It is important to avoid caulking areas where the flashing and trim meet, as this can trap moisture and lead to rot or staining. Flashing should be used as the primary method of moisture control, with caulking serving only as a secondary measure.
Ground Clearance and Air Space
To prevent water damage and staining, cedar siding should be installed at least 6 inches above the ground. This helps to minimize contact with moisture and soil. For vertical siding, the bottom end grain should be treated with a water repellent to further protect against wicking.
In some cases, an air space between the siding and rigid foam sheathing can be beneficial. This allows for better moisture ventilation and reduces the risk of staining or buckling. Furring strips can be used to create this air space when installing over foam sheathing.
Material and Fastening Requirements
Nail Selection
Choosing the right nails is crucial for the longevity and appearance of cedar siding. The documentation emphasizes the use of corrosion-resistant nails such as hot-dipped galvanized, aluminum, or stainless steel. Copper nails should be avoided, as they can react with the natural oils in cedar and cause staining.
Stainless steel nails are recommended, especially when using transparent stains. Two types of stainless steel are commonly used: No. 304 for general applications and No. 316 for coastal environments. These nails resist corrosion and maintain their integrity over time.
Nail Type and Size
To minimize splitting and ensure secure fastening, splitless nails are recommended. These nails have thin shanks and blunt points, which reduce the likelihood of cracking the wood. For greater holding power, ring-threaded or spiral-threaded shanks are preferred.
The appropriate nail size depends on the thickness of the cedar siding. For example, bevel siding with a thickness of ½ inch or less requires 13 mm or smaller nails, while thicker boards require larger nails for secure fastening. A detailed table in the documentation provides specific recommendations for nail sizes based on siding thickness and type.
Caulking and Sealing
Caulking is an important step in sealing gaps and preventing water intrusion. However, it is not a substitute for proper flashing and should be used in conjunction with it. The documentation recommends using non-hardening caulks such as polyurethane, polysulfide, or latex-silicone. Pure silicone caulks are not recommended for cedar, as they can cause adhesion issues and are not compatible with the wood’s natural oils.
Caulking should be applied to all joints, including butt joints, window and door openings, and trim areas. It is important to maintain the recommended overlap between siding panels to prevent wind-driven water from seeping through. If the overlap is reduced, it can compromise the siding’s ability to resist water damage.
Installation Techniques for Common Cedar Siding Profiles
Bevel Siding
Bevel siding is one of the most commonly used cedar siding profiles. It is installed horizontally and typically features a 1/8-inch reveal between panels. The recommended overlap is 1/8 inch, which helps to direct water away from the wall and prevent staining.
To install bevel siding, start at the bottom of the wall and work upward. The first panel should be installed at least 6 inches above the ground and secured with splitless nails. Each subsequent panel should be placed with a 1/8-inch gap to allow for expansion and contraction.
Tongue & Groove Siding
Tongue & groove siding is designed for tight, seamless installation. The interlocking profile helps to reduce air and water infiltration while maintaining a clean, finished appearance.
When installing tongue & groove siding, it is important to ensure that the grooves are aligned and that the panels fit snugly together. Splitless nails should be used to avoid splitting the wood, and the recommended nail size depends on the thickness of the panel.
Board & Batten Siding
Board & batten siding consists of wide boards and vertical battens that cover the seams. This style offers a distinctive look and is suitable for both horizontal and vertical installations.
For horizontal board and batten siding, the boards are installed first, followed by the battens. The battens should be placed over the seams and secured with splitless nails. For vertical installations, the boards are installed vertically, and the battens are applied horizontally to cover the joints.
Shiplap Siding
Shiplap siding features overlapping panels that are typically installed horizontally. The overlapping design helps to direct water away from the wall and provides an additional layer of protection against moisture.
When installing shiplap siding, the panels should be staggered for a more even appearance. The recommended overlap is 1/8 inch, and splitless nails should be used to secure the panels.
Special Considerations for Rigid Foam Sheathing
Rigid foam sheathing is a high-performance insulation material that offers excellent thermal resistance. However, it has little or no nail-holding power and can cause issues if not installed properly.
When applying cedar siding over rigid foam sheathing, it is important to use thicker siding panels in widths of 8 inches (203 mm) or less. Thicker, narrower panels are more stable and less prone to warping.
Kiln-dried cedar is the most stable option for use with rigid foam sheathing. It should be prefinished according to the manufacturer’s recommendations to ensure compatibility with the foam.
An air space between the siding and foam sheathing can be beneficial in severe climates. This can be achieved by installing furring strips before attaching the siding. The air space allows for better moisture ventilation and reduces the risk of staining or buckling.
Building paper or a similar weather-resistant barrier should be applied over the foam sheathing to provide an additional layer of protection.
Maintenance and Longevity
Proper installation is the first step in ensuring the longevity of cedar siding, but regular maintenance is also essential. This includes inspecting and replacing caulk as needed, checking for signs of water damage, and reapplying protective finishes.
Cedar siding can be finished with a variety of stains and sealants to enhance its appearance and protect it from the elements. Light-colored finishes are recommended to maximize heat reflection and reduce dimensional movement.
In coastal or high-moisture environments, it is especially important to use corrosion-resistant fasteners and apply a protective finish regularly. This helps to prevent staining, warping, and premature deterioration.
Conclusion
Cedar siding is a durable and attractive option for exterior wall finishes, but its success depends on proper installation techniques and material selection. From wall construction and flashing to fastening and sealing, each step plays a critical role in ensuring the longevity and performance of the siding. By following the guidelines outlined in this article, builders and DIY users can achieve a professional, long-lasting cedar siding installation.