Rake the area where you would like to build a dance floor outdoors, or, if indoors, clean the area. Use a bar level to check several spots to make sure the area is level enough to work on.
Count the number of 2 by 4’s on each pallet. Measure the length of the 2 by 4's in the pallets, and calculate how many will be needed to create a standard 16 by 16 foot dance floor. You will need to create a 16 foot square frame built out of four, 16-foot long sections of 2 by 4's.
Take out each pallets' 2 by 4’s with a hammer's end to remove all screws or nails. Build a frame measuring 16 feet per side. Build it according to how long the top boards are, so the pieces can be screwed into the frame. Create two to three 16-foot long joining pieces inside the frame. For example, if the 2 by 4's are 4 feet long, you will need to build three, evenly-spaced 16 foot joining seams inside your frame. Secure the frame at each joint using the 3-inch long screws.
Place the pieces of pallet wood one at a time over the frame. These pieces will form your dance floor. Screw them in place using the 1-inch, flat-topped screws. Four screws per board, two at each end, should do. Screw them in tightly so they are flush with the wood and so they won't snag clothing or trip any dancers.
Sand the entire floor with an electric sander. Seal the floor using a floor sealant or filler to level any cracks or dips that may be in the wood.