What Are The Best Screws For Pressure Treated Wood

What Are the Best Screws for Pressure Treated Wood?

Choosing the right screws for pressure treated wood is crucial for a long-lasting and secure project. Pressure treated lumber, while incredibly durable, presents unique challenges due to its chemical composition. Using the wrong fasteners can lead to premature failure, stripped threads, and compromised structural integrity. This article will guide you through selecting the best screws for your pressure-treated wood projects, considering factors like material, coating, and size.

Understanding the Challenges of Pressure Treated Wood

Pressure treated lumber is infused with preservatives, typically copper azole, chromated copper arsenate (CCA – now less common due to environmental concerns), or other chemical compounds, to protect it from rot, decay, and insect damage. These chemicals can react with certain metals, causing corrosion and weakening the connection. This is why selecting the appropriate screw type is paramount.

Screw Material: The Key to Success

The most important factor to consider is the screw's material. Stainless steel screws are generally the best choice for pressure treated wood due to their exceptional resistance to corrosion. Look for grades 304 or 316 stainless steel. Grade 316 offers superior corrosion resistance in harsh environments, making it ideal for outdoor projects constantly exposed to the elements.

While galvanized steel screws are sometimes used, they are not as resistant to corrosion as stainless steel, particularly in contact with the chemicals in pressure treated lumber. Over time, galvanization can break down, leading to rust and screw failure.

Avoid using plain steel screws, as they are highly susceptible to rust and corrosion in pressure treated wood.

Coating Considerations: Enhancing Durability

Even with stainless steel, a suitable coating can further enhance performance. Look for screws with a coating designed to resist corrosion, even in damp conditions. While not strictly necessary with high-grade stainless steel, a coating can offer additional protection and prolong the life of the screw.

Choosing the Right Screw Type & Size: A Matter of Application

The type and size of screw you need depend heavily on the application and the thickness of the wood. For most projects, exterior-grade, coarse-threaded screws provide excellent holding power in pressure-treated lumber. The coarse threads help create a stronger bite and prevent the wood from splitting.

Consider these factors when selecting screw size:

• Wood thickness: Use longer screws for thicker pieces of wood to ensure adequate penetration and secure fastening.
• Application: Heavily loaded applications (like decks or fences) require larger diameter screws for greater strength.
• Screw head type: Choose a head type appropriate for your project's aesthetics and functionality (e.g., countersunk, pan head, etc.).

Tips for Success with Pressure Treated Lumber and Screws

• Pre-drilling: Pre-drilling pilot holes is almost always recommended, especially when working with pressure treated wood, to prevent splitting and ensure easier screw installation. The pilot hole should be slightly smaller than the screw's shank diameter.
• Using a good quality driver: Using a driver with the correct bit size and applying appropriate torque will prevent stripping the screw head.
• Consider the environment: If your project is exposed to extreme weather conditions (e.g., salt spray near the coast), use higher-grade stainless steel screws for added protection.

By carefully considering these factors, you can choose the best screws for your pressure treated wood project and ensure the longevity and structural integrity of your work. Remember, investing in high-quality fasteners is a worthwhile investment in the overall durability of your project.