Before you start to build composite decking, you may want to gather enough materials first. Not having enough can cost you more time and effort, wasted on going to hardware stores to buy more. Since you will be using screws throughout the installation process, you will need a lot of them. So, how many screws do I need for composite decking. You also need to know how much you would need to drill on various parts of your deck. 

How Many Screws Should You Get?

decking screws

There isn’t a straightforward answer to this question, as not all decks are the same. Several factors might affect how much you screws you will need. Here are a few things you should consider. 

  1. Deck Dimensions – First, you will need to consider the dimensions of your deck, including the height, width, and length. The bigger and more spacious your deck will be, the more screws you will need. 
  1. Decking Board Spacing – Composite decking boards require spacing in between the boards. Decking boards need space to give way for occasional shrinking and expansion due to temperature changes. The more spaced the deck boards are, the more screws you will use. 
  1. Decking Board Width – You will also need to consider your decking boards’ width. Decking board widths range from 4 inches to 8 inches, with 6-inch boards being the most commonly used. 
  1. Joist Spacing – Another crucial detail to consider is the frame. Similar to decking boards, you also need to have proper spacing, especially for the joists. In decking, it’s often 12″. 16″, or 24″ inch on-centre. The joist spacing will determine how stable the boards will be. The more spaces in-between the joists, the more screws you will need. 
  1. Screws per Decking Board – You will also need to count how many screws you will use for each board. Most decking boards will require two screws each to fix them securely onto the floor joists. As for decking boards to rim joists, many recommend using at least three screws. 
  1. Hidden Fasteners – Hidden fasteners don’t use the same traditional method of laying the decking boards. These fastening systems use clips inserted into the grooves of the deck boards. As there are several varieties of clips and fasteners, the number of screws needed can vary. In most cases, you will often need half of what you will usually use. 

Manually counting all the screws you need is possible but would take a lot of time and effort. Most professional builders estimate the number of screws by the total square footage of the deck. For standard composite decks with 6-inch wide boards and 16″ OC joists, you will need at least 350 screws for every 100 square feet. Since most hidden clip fastener systems require fewer screws, you will need at least 175 screws for the same square footage. 

Use an Online Calculator

Besides manually calculating how many screws you will need, you can also use various calculators on the internet. However, you will need to know the specifics of your planned deck design to use them. You need to input the deck dimensions, boards and joists spacing, and how much screws you plan to use per decking board.

You can also check in with your decking board suppliers or manufacturers. They can supply you with an estimate of how many screws you will need. Some of them can even give you other advice and instructions for building a deck. It’s worth giving them a call.