A platform deck, also sometimes called a floating deck, is a deck that sits close to the ground and typically doesn't have railings. This type of deck is a cost-effective alternative to other decking options. If you have a little help, you can generally complete a small or medium-sized platform deck in one day.
Determine the dimensions for your platform deck: 10 feet by 10 feet is a common size for platform decks. In addition to selecting the dimensions for the deck's length and width, determine how tall your platform deck needs to be. Generally, you will want it slightly lower than the threshold for your exterior door, or a full step's distance below the threshold.
Prepare the building site for your platform deck. Clear away debris and level the ground where your deck will be located. To do this remove or add soil and gravel to get the grade you want.
Set up the cinder block (concrete block) foundation for your platform deck. You will want to place and level your cinder blocks at critical support points such as on the corner, at the center point of each side and down the middle of the platform deck. Use a level and a string to check that all the cinder blocks line up and are level with each other. This is an important step to master, as it will determine how level your platform will be. If your cinder blocks are not level add or remove sand/dirt underneath the blocks to make them level.
Frame out your platform deck in a square or rectangle based on the measurements from step one. Use decking screws to secure the lumber together. Then place the outside frame on your cinder blocks. Install joist hangers or deck hangers every 16 inches on center on both the header and footer of your deck frame, adjust as needed to space the hangers evenly. Make sure the hangers line up or else your support beams will not fit properly into the hangers. To install the hangers you generally just need to screw them into place.
Measure the distance between the joist hangers. Cut your support beams and slip them into the hangers.
Screw on the decking so that there are two screws per intersection with each support beam. When you are done snap a chalk line on the ends of the deck and cut along this line. This will remove the excess decking and create a nice straight line for your deck. Finish the deck by sanding and staining the decking.