As a construction specialist with a focus on woodwork, I often get asked about the best types of screws to use with pressure treated wood. Pressure treated wood is a popular choice for outdoor projects due to its durability and resistance to rot and insect damage. However, because of the chemicals used in the treatment process, it's crucial to select the right type of fasteners to ensure both the longevity of the wood and the integrity of the construction.

Fasteners for preservative-treated wood should be chosen with care. According to the American Wood Protection Association (AWPA), there are specific requirements for fasteners used in conjunction with pressure treated wood. The AWPA standard R317.3.1 outlines that fasteners for preservative-treated wood **shall be of hot dipped zinc-coated galvanized steel, stainless steel, silicon bronze, or copper**. These materials are chosen for their resistance to corrosion and their compatibility with the preservatives used in the wood treatment process.

### Hot Dipped Zinc-Coated Galvanized Steel
This is a common choice due to its affordability and availability. Galvanized screws are coated with a layer of zinc, which protects the steel from rusting. However, it's important to ensure that the galvanization is of the "hot dipped" variety, as this provides a thicker and more durable coating than other methods such as electroplating.

### Stainless Steel
Stainless steel screws are another excellent option, particularly for projects that will be exposed to harsh weather conditions or are in coastal areas where salt spray can cause rapid corrosion of other materials. Stainless steel offers superior corrosion resistance and is strong, making it a top choice for many professional builders.

### Silicon Bronze
Silicon bronze screws are known for their excellent corrosion resistance and are often used in marine environments. They are more expensive than galvanized or stainless steel screws, but their longevity and resistance to corrosion make them a worthwhile investment for projects where aesthetics and durability are paramount.

### Copper
Copper screws are a traditional choice that offers both aesthetic appeal and good corrosion resistance. While they are more expensive, they can add a touch of elegance to a project and are well suited for use in areas with high humidity or where the wood will be in contact with the ground.

When selecting screws for pressure treated wood, it's also important to consider the size and type of screw. For structural applications, it's recommended to use screws that are at least 2-1/2 to 3 inches long for every inch of thickness of the wood being joined. Additionally, coarse-thread screws are generally preferred for outdoor use as they provide better holding power in wood.

In conclusion, the choice of screw for pressure treated wood should be based on the specific requirements of the project, including the environment in which the project is located, the expected lifespan of the construction, and the aesthetic considerations. By adhering to the AWPA standards and selecting the appropriate fasteners, you can ensure that your project will stand the test of time.

read more >>

R317.3.1 Fasteners for preservative-treated wood. Fasteners for preservative-treated wood shall be of hot dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper.read more >>