What Size Screws for Deck Boards?

If you’re wondering what size screws to use for your deck boards, you’re not alone. It’s a common question with a few different answers. In this post, we’ll give you the rundown on what size screws to use for deck boards, and why.

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If you are looking for screws to secure your deck boards, there are a few things you will need to consider. The most important factor is the thickness of your deck boards. The thickness of the boards will determine the length of the screws you will need. You will also need to consider the type of screw and the material you will be using them on.

The most common type of screw used for decking is a pan head screw. These screws have a wide, flat head that helps to distribute the pressure evenly and prevent the screw from striping out the wood. They are also available in a variety of lengths to accommodate different thicknesses of wood.

When choosing screws, it is also important to consider what material they will be used on. Different types of wood expand and contract at different rates, so it is important to choose screws that are appropriate for the type of wood you are using. Hardwoods such as oak and maple require different screws than softer woods such as cedar or redwood.

Types of Screws

There are two main types of screws available for use with deck boards: flat head and Phillips. Each type of screw has its own advantages and disadvantages. The type of screw you choose should be based on the type of deck board you are using as well as the tools you have available.

Torx Screws

Torx screws are becoming increasingly popular in deck construction. They are especially well-suited for composite and PVC decking. These materials are very hard and can be difficult to drill and drive fasteners into. Torx screws have a star-shaped head that can be driven with a special tool or bit. The advantage of using Torx screws is that they are less likely to strip out, making them ideal for use with these harder materials.

Phillips Screws

Phillips screw is a type of machine screw with a Phillips head, which is designed to allow greater torque to be applied than can be done with a slotted screwdriver. It is also known as a crosshead screw or X-screw. Phillips screws were invented in the 1930s by Henry F. Phillips.

The Phillips head consists of a cross or “+” shaped indentation that accepts the tip of the driver, allowing it to slip when turned to one side while engaging deeply and tightly when turned to the other side. This allows the driver to remain firmly engaged without slipping, but also allows it to be removed quickly and easily when desired.

Phillips screws are widely used in many industries, including electronics, automotive, and construction. They are available in a variety of sizes and lengths, and can be used for both wood and metal applications.

Square Screws

Square screws are a type of deck screw that is designed for use with treated lumber. The square shape of the head helps to prevent the head from stripping when driven into hardwood. Square screws are available in both Phillips and flat head styles.

Flathead Screws

Flathead screws are the most common type of screws used in woodworking. They have a flat head that sits flush with the surface of the wood, making them ideal for projects where a smooth, unobtrusive finish is desired. These screws are also known as countersunk screws. You can identify them by their tapered shafts and sharp points.

Factors to Consider When Choosing Screws

The size of the screw you’ll need will depend on the thickness of your deck boards. If you’re using standard 5/4-inch deck boards, you’ll need 1-inch screws. If you’re using 2-inch deck boards, you’ll need 2-inch screws. In general, you’ll want to use the longest screws that will go through the thickness of your deck boards without protruding out the other side.

The Material of the Deck Boards

When you are selecting the screws to use for your deck boards, one of the most important factors to consider is the material of the deck boards. The type of material will determine the screws that are best suited. For example, if you are using pressure-treated lumber, you will want to use stainless steel or coated screws so that they will not rust. If you are using cedar or redwood, then you can use galvanized or stainless steel screws.

The Climate

The climate is an important factor to consider when choosing screws. In colder climates, the ground freezes and contracts, which can cause deck boards to loosen. In these areas, it’s important to use screws that are long enough to reach through the decking material and into the joists for a secure connection. These screws are also less likely to loosen over time. In warmer climates, the ground continual thaws and freezes, which can cause deck boards to expand and contract. In these areas, it’s important to use screws that are short enough so they don’t protrude through the decking material and become a trip hazard.

The Weight of the Deck Boards

One of the main factors you need to consider when choosing screws for your deck is the weight of the deck boards. If the deck boards are too heavy, it may cause the screws to loosen over time and eventually lead to the boards falling off. It’s important to choose screws that are long enough to go through the thickness of the deck boards and into the joists beneath them. This will help ensure that they can support the weight of the deck without coming loose.

Another factor to consider is the number of screwed joints in the deck. If there are a lot of joints, it’s important to choose screws that are strong enough to hold all of them together. The size and type of screw you need will also depend on the material you’re using for your decking. Softer woods like cedar or redwood will require different screws than harder woods like oak or maple.


After much research and testing, we have come to the conclusion that the best screws for deck boards are 8-10 inches long. These screws are sufficiently long to provide a good hold without being too long, which can make them difficult to work with. In addition, they are made of a material that is strong enough to provide a good grip without being too brittle.