Decking will create the floor of your deck. There are many options depending on your tastes and budget. Use the decks.com floor material calculator to determine the number of linear feet of decking you will need for your project. This material can be wood, composite, vinyl, or aluminum. Wood deck boards can be screwed or nailed in place across the deck frame. Wood decking will require staining to protect the wood. You should stain your deck soon after it is completed and every few years afterwards. Over time unprotected wood will check or crack and gray.
Composite materials are available in a wide variety of colors and textures. The primary advantage of composite decking over wood is that it doesn't require staining. Most composite decking comes with a limited warranty. Make sure your composite decking material has an ESR report and is approved for use in your area. There solid composites and hollow composites. Some are tongue and groove and others include a slot for hidden fasteners. Composite decking should be spaced to prevent buckling due to thermal expansion. Always follow the manufacturer's installation instructions.
Vinyl decking is a low maintenance product that it more scratch and stain resistant than composite decking. Aluminum decking is another option that can also create a watertight area under the deck.