Choosing Fasteners for Hardwood Siding

The Importance of Fastener Material

The material of your fastener is paramount when working with hardwood siding. Hardwoods, especially certain species, contain natural tannins and extractives that can react with incompatible metals. This reaction can lead to unsightly black staining on the wood surface, a common issue with steel fasteners.

Stainless steel, specifically 304 or 316 grade, is generally recommended for exterior hardwood siding applications. Grade 304 offers good corrosion resistance for most environments, while grade 316 provides superior resistance to salt water and other harsh conditions, making it suitable for coastal projects. Hot-dipped galvanized fasteners can be an alternative in some cases, but their coating can be compromised during installation, potentially leading to rust and staining. Always verify compatibility with the specific hardwood species you are using and consult manufacturer guidelines.

Fastener Length and Penetration

The length of the fastener is crucial for secure attachment.

Insufficient penetration can result in boards loosening over time, especially with wood movement due to changes in humidity and temperature. Conversely, excessively long fasteners are unnecessary and can be more difficult to install, potentially splitting the substrate or causing issues with interior finishes.

Choosing the Right Fastener Type

Several fastener types are suitable for hardwood siding, each with specific applications:

Face Nailing: This method involves driving fasteners directly through the face of the siding board into the framing. Ring-shank or screw-shank nails are often preferred for their superior holding power compared to smooth-shank nails. Screws, particularly self-tapping stainless steel screws, offer even greater holding strength and can be removed if necessary, which is useful for future maintenance or repairs. While visible, face nailing provides a very secure attachment.

Hidden Fasteners: For a cleaner aesthetic, hidden fastening systems are popular. These systems typically involve clips or specialized screws that attach to the back or edge of the siding board, securing it to the furring without visible fasteners on the face. Hidden fasteners often require specific siding profiles and meticulous installation to ensure proper alignment and drainage. Examples include tongue-and-groove profiles designed for clips or systems that allow screws to be driven at an angle through the tongue.

Each method has trade-offs in terms of appearance, installation effort, and long-term performance. Consider the desired aesthetic and the specific siding profile when making your choice. Lumber Plus offers a variety of hardwood siding options, including Ipe, Cumaru, Garapa, Angelim, Jatoba, and Tigerwood, which can be installed using appropriate fastening methods. We also supply Maximo Accoya and thermally modified wood products like Scandinavian thermally modified wood, Ayous, Ash, and Clear Radiata, which may have specific fastener recommendations.

Explore our range of siding and cladding at /siding-and-cladding.

Worked Example: Fastener Selection for Ipe Siding

Consider a hypothetical project for a residential facade using 1x6 (nominal) Ipe hardwood siding, installed horizontally over 3/4-inch furring strips, with studs spaced at 16 inches on center. The project is located in a general suburban environment, not directly on the coast.

Siding Thickness: A 1x6 nominal Ipe board typically measures about 3/4 inch actual thickness. The furring strips add another 3/4 inch.

Substrate Penetration: We aim for at least 1.25 inches of penetration into the structural studs.

For a hidden fastener system, stainless steel clips or screws designed for hardwood would be considered.

Fastener Type: For a clean, modern look, a hidden fastening system might be preferred.

Considerations for Exposure and Environment

The environmental conditions of your project site significantly influence fastener selection. Coastal areas, for instance, demand fasteners with higher corrosion resistance due to salt spray. In such cases, 316-grade stainless steel is often a better choice than 304-grade.

Areas with high humidity or frequent rain also put more stress on fasteners. Even in inland locations, proper drainage and ventilation behind the siding are essential to prevent moisture buildup that could accelerate fastener degradation. Always consider the local climate and specific microclimates of the building when making your final selection.

Installation Best Practices

Proper installation techniques are just as important as selecting the right fastener. Pre-drilling pilot holes is highly recommended for hardwood siding to prevent splitting, especially near board ends or when using larger diameter screws. This is particularly important for dense hardwoods like Ipe and Cumaru.

Maintain appropriate spacing between boards and at butt joints to allow for natural wood movement. Fasteners should be driven straight and flush with the surface, or slightly countersunk if desired and appropriate for the fastener type. Avoid overdriving fasteners, as this can damage the wood fibers and reduce holding power. For hidden fastening systems, follow the manufacturer's specific instructions for spacing and clip placement.

Before you order

• Verify the hardwood species and its specific recommendations for fastener material.
• Determine the total thickness of the siding, furring, and sheathing to calculate required fastener length.
• Confirm the minimum penetration depth into structural framing (typically 1 to 1.5 inches).
• Assess environmental exposure (e.g., coastal, high humidity) to choose appropriate stainless steel grade (304 vs. 316).
• Decide between visible (face nailing) or hidden fastening methods based on aesthetic preference and siding profile.
• If face nailing, choose ring-shank nails or screws for better holding power.
• If using hidden fasteners, ensure compatibility with the specific siding profile and system.
• Plan for pre-drilling pilot holes, especially for dense hardwoods.
• Account for wood movement by allowing appropriate spacing between boards.

Confirm installation details, approved uses and warranty terms in the current instructions for the exact product and profile. Your installer should verify the substrate, structure and applicable project requirements.

Questions to help you decide

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