Deck 103

Hardware Options

Hardware for decks should be weather resistant. The extra cost for longer lasting fastners is usually small relative to the cost of the whole project.

Machine Bolts

Properly sized and installed, machine bolts provide exceptional strength for major structural connections. For most deck loads, 3/8 inch diameter bolts are adequate, although some longer bolt lengths(more than 7 inches) are availabale only in wider diameters. If you are unsure which size to use, check with your local building inspector. Use washers, under both nut and bolt head, to help distribute the pressure. Drill bolt holes that are the same diameter as your bolt shanks. Figure the length by adding about 1 inch to the total thickness of wood you intend to bolt. You need at least ½ inch of thread protruding to install a nut and washer.

Carriage Bolts

Carriage bolts have a square section of shank just under the head. The shank engages the wood, and keeps the bolt from turning when you tighten the nut. Figure length by adding about an inch to the total thickness of wood you will bolt together. Tighten the nut with a socket wrench. Stop once the bolt head has pulled into the wood and you see or hear the wood fibers start to crush under the washer. If you install carriage bolts in wet wood, the bolts will need to be retightened after the wood dries and shrinks.

Lag Screws

Lag screws are long, thick screws with hexagonal heads. They have a greater resistance to withdrawal and can hold a greater load than nails can. Though carriage bolts are stronger and often easier to install, lag screws are the best choice when you cannot reach around to fasten a nut and washer. Lag screw diameters range from 1/4 to 3/4 inch. Lengths range up to 10 inches.

Nails

Nails for deck construction must resist corrosion and hold tight as the wood expands and contracts. Hot-dipped galvanized nails have a dull grey lumpy coating. This rough texture helps them to hold, but makes them harder to drive. Spiral shank, galvanized nails resist withdrawal far better than standard nails. They are also a bit harder to drive than standard nails. Stainless steel, ring shank nails are well suited for corrosive environments like salt air. Don't hold nails in your mouth when you work. No matter how mant times you've seen tradesmen doing it. Nail coatings are not a source of nutrition and can sometimes cause sores in your mouth.

Screws

Decking screws hold far better than nail. Buglehead screws are manufactured with sharp threads and a horn shaped head so they can be power driven, usually without pre-drilling. Usa a screw gun or a variable speed drill to drive them. Deck screws are sold with phillips or square head. Driver bits cost under a dollar either style. The screw thread should penetrate at least as deep in the holding member as the piece to be held is thick. Thus, a 1½ inch deckboard requires a three inch screw.

Framing Hardware

A wide variety of sheet metal connectors are available to strengthen the joints between wood framing members. Joist hangers, post bases and post to beam connectors are commonly used in deck building. Some connectors, like joist hangers, speed the work and provide greater strength than the wood to wood connections they replace. Connectors allow nails and bolts to be oriented for maximum holding power in the wood.

Updated:08/06/03 07:41 PM