How to Choose the Right Fastener for Your Deck

Choosing the right fasteners for your deck can feel like an overwhelming decision. Screws, nails, and anchoring hardware have to stand up to many years of moisture, so it's important to select a durable fastening system when building a DIY deck. Standard galvanized fasteners, for example, have a single protective coating, which might flake off and rust. Double-dipped galvanized fasteners are better protected, but you'll get the best life from coated fasteners made for decks. Stainless steel is costly but one of the best deck fastener materials available. We'll walk you through all of the deck fastener options, plus provide pros and cons for each material.

1. Nails and Screws

Nails are sized by their length, designated by a penny, or d, size. Gauge, or diameter, increases as the penny size increases; a 16d nail is both longer and fatter than an 8d.

• Common nails, used for general framing, have large heads and thick shanks. They hold well but are hard to drive and may split the wood.
• Box nails, thinner than common nails of the same size, reduce splitting in 3/4-inch or thinner stock.
• Ringshank and spiral nails grip the wood fibers and don't easily work their way out. They are very difficult to remove.
• Finishing nails have slender shanks and small, barrel-shaped heads. Use them for trim work and countersink the heads.
• Casing nails are heftier versions of finishing nails and provide more holding power.

Screws come in a wide array of styles. A good all-around choice is #10 decking screws—generally in 2 1/2- to 3 1/2-inch lengths. Decking screws are sharp, tapered, self-sinking, and coated for corrosion resistance. With a cordless drill/driver, you can drive them about as fast as nails. Be sure to match your screwdriver bit to the screw head (or vice versa). Decking screws generally are machined with a Phillips, square, or combination head. Square heads drive more securely.

How to Choose Between Nails and Screws for Deck Fasteners

Screws are nearly as quick to drive as nails and have greater holding power. As long as you drive them accurately, without stripping the head, screws are easier to remove than nails. However, many people don't like the way screw heads look because a small amount of water will puddle inside them. Water will not puddle on a nailhead unless you drive it too deep. To an experienced builder, driving nails is a bit faster than driving screws.

However, if you miss a nailhead with the hammer, or if you drive the nail too far, you will mar the wood. And it is difficult to remove a nailed board without damaging the board.

2. Framing Hardware

Framing connectors strengthen the joints between framing members. Not too long ago, framing members were joined with nails or screws, but most current building codes now require framing hardware.

Attach joists to the side of a ledger or beam using joist hangers. At the corner, either cut a joist hanger in half using tin snips or use an angle bracket. Angled joist hangers accommodate joists that attach at a 45-degree angle.

Where a beam sits on top of a post, a post cap provides a reliable joint. If joists sit on top of a beam, many local codes allow you simply to angle-drive screws to secure the joists to the beam. Other local building departments require special seismic (or hurricane) ties, which add lateral strength.

A post anchor secures a post to a concrete pier and supports it so the bottom can dry between rainfalls. Get the style that you can adjust so you can fine-tune the posts and keep them on the same line.

3. Heavy-Duty Screws and Bolts

To fasten a large piece like a post, use either a lag screw or a carriage bolt. Bolts are stronger and can be tightened in future years if the lumber shrinks. Always use washers under the head of a lag screw or the nut on a carriage bolt so that the fastener does not sink into the wood.

Attach a ledger to brick, block, or concrete with lag screws and masonry anchors. Hold a ledger temporarily with masonry screws, which are not quite as strong but are easier to drive and don't require anchors.

4. Other Types of Deck Fasteners

You can avoid visible nails and screws completely with invisible deck fastening systems. Invisible fasteners come in many forms. They are more expensive and more time-consuming to install, but they leave a clean, uncluttered deck surface. They are especially useful in contemporary deck designs or with complicated decking patterns because they don't distract from the pattern of the decking itself. Deck clips are the easiest to install because you can work from the top of the deck. Continuous fasteners require driving screws from underneath and are better suited to raised decks.

You can also use masonry fasteners. With this hardware, an anchor bolt comes preassembled so its sleeve expands against the sides of a predrilled hole as you tighten the bolt. Drill a hole of the same diameter and at least 1/2 inch longer. Blow out the dust and drive the bolt with the nut just at the top of the threads. Make sure the bolt doesn't turn when tightening. Plastic or soft-metal expansion shields are designed to spread their sides as you tighten the fastener. Drill a hole of the same diameter and length of the shield, and tighten the screw.

Power Fasteners

Power fasteners, such as nail guns, screw guns, and power-actuated fasteners, speed up carpentry projects. Some are powered by compressed air, others use a power cell or chemical or explosive charges. Power fasteners are expensive, but you can rent the tool you need at most rental stores. Plus, they offer many advantages over a traditional hammer and nails:

• The gun can be operated with one hand, leaving the other hand free to steady the work and keep it aligned.
• A single blow drives the nail from the gun, eliminating the repeated hammer blows that can jolt a piece out of alignment.
• The risk of bending a nail or missing the nailhead and denting the deck is eliminated.
• Nails used in nail guns are thin and have blunt tips that seldom split the wood piece.
• You can nail in places or positions that would be difficult to reach with a hammer.
• Many guns can be set to countersink the fasteners or leave them flush with the surface.

How to Choose the Right Size Fastener

Use these tips to get the sizing right for your deck fasteners:

• Decking: Fasten 5/4 decking with 2 1/2-inch coated screws or 12d ringshank or spiral nails.
• Railings: Attach 1x trim, rails, and cap rails with 10d, 8d, and 6d galvanized, finishing, or casing nails.
• Framing: Use 10d or 16d common, spiral, or ringshank nails (or decking screws) in 2x stock; 8d or 10d box or ringshank nails (or shorter deck screws) in thinner stock. Attach framing hardware with the fasteners supplied by the manufacturer, 16d nails, or 3-inch deck screws. Check with your building inspector—some codes prohibit attaching framing connectors with screws.