How many screws do I need to build a deck?
The number of screws you need to build depends on the size and layout of the deck, the type of fasteners you choose, and the space between the deck boards.
To calculate the total number of deck screws needed, divide the total square footage of your deck by the coverage area of one deck board. Let's see how we arrived at this solution.
-
Deck Size: Measure the dimensions of your deck to calculate the total square footage. Break down each section into the simplest squares and rectangles and multiply the length by width for each. Finally, add them to get the total square foot.
-
Spacing between Deck Boards: The material for decking boards can greatly impact the distance between them. Generally, the spacing must be around 1/8 to 1/4 inch for hardwood deck boards and 3/16 to 1/4 inch for pressure-treated wood and composite boards. The spacing along the length of the board can be consistent but must be more at the board ends as boards expand lengthwise.
-
Type of Fasteners: How many deck screws you use depends on the kind and combination of fasteners you use. Deck screws are better at holding together two pieces of wood, while wood screws are made from softer steel than deck screws, making them more likely to strip when driven into hardwoods. Irrespective of how many fasteners you use, keeping them evenly spaced is always recommended. The deck board thickness and the material you're using affects the size and the screw length. You also want to ensure that you pick corrosion-resistant screws.
-
Coverage Area: Calculate the surface area covered by one decking board. For example, if you have 5.5-inch-wide deck boards and you're spacing them 1/4 inch apart, each deck board covers approximately 5.75 square inches.
-
Total Deck Screws Needed: To calculate the total number of deck screws needed, divide the total square footage of your deck by the coverage area of one deck board. This will give you the approximate number of deck screws required. Be sure to add a small buffer for extras and replacement screws, typically around 10-15% of your calculated total, to account for any unexpected needs and build a secure deck.
You can use this simplified formula to help you estimate the number of screws needed for your deck:
Total Screws Needed = (Total Square Footage of Deck) / (Coverage Area of One Deck Board)
Remember that this is a rough estimate and doesn't account for the kind of joist hangers and hidden fasteners you need. The exact number of screws and the right size may vary based on the deck design, the layout, structural components like railings and stairs, and the variety of composites used. To get a precise count, it's best to consult with your deck plans or the manufacturer's guidelines for your chosen screws.
