How to Build a Floating Deck

A floating deck with a table and chairs set on it surrounded by plants.
What You'll Need
Tape measure
Leveling tool
Auger (or shovel)
Chalk line (or spray paint)
Concrete deck blocks
Pressure treated lumber
Miter or hand saw
Deck screws
Circular saw

The idea of constructing a deck can be intimidating for anyone, especially considering all the planning and permits involved in the process. However, a floating deck is an elegant and simpler alternative to a traditional deck that is attached to a home. Not only are floating decks easier to build, but they can be placed anywhere in a yard and offer a great place to relax and enjoy the outdoors. By following these simple steps, you can build a floating deck that is sure to add enjoyment to your outdoor living for years to come.

Step 1 - Take Measurements

The size of the space in your yard will largely determine the size of the floating deck. After measuring the length and width of the intended space, draw out the measurements of the deck, including its length, width, depth, and inner framework. With these plans in hand you can start the process of laying down a good foundation.

Step 2 - Level the Ground

After marking the outer boundaries of the deck, you can start leveling the ground. This is a critical step that should not be overlooked. If the ground isn’t level then the deck won’t be, either. First, dig down until you reach the hard ground and then start making things level. A laser level is handy for this and will ensure the ground is completely level.

Step 3 - Outer Deck Blocks

With the ground level, dig post holes for the deck blocks. The easiest way to do this is to rent an auger, but a shovel will also get the job done on a limited budget. There should be a block in each corner of the deck, with each block placed six inches deep. These blocks will bear the weight of the deck, so it is important to make sure they are level and on solid ground.

Step 4 - Interior Deck Blocks

A construction worker framing together a deck.

For the interior support structure, start by measuring two feet from each of the four corner blocks. Use either string or spray paint to connect these measurements in straight lines along the short side of the deck. Repeat this process for the long side of the deck. The end result should be interior areas where the lines cross. In each of these intersections, dig down and place a deck block.

Step 5 - Setting Blocks

It's important that each of the deck blocks are level—and that they remain level long after the deck is finished. In order to make sure everything stays as flat as possible, mix in some concrete around the blocks. Before leaving things to dry, make sure all the blocks are level by using a straight board and level.

Step 6 - Lay Down Joists

The deck joists will make up the framework of the floating deck. Make sure you use pressure treated lumber, which is better suited for outdoor climates. After everything has dried, simply lay down the deck joists in the blocks. You’ll need to do some cutting and measuring as you go along, but if the blocks are each two feet apart then this process should be quick and easy.

Step 7 - Placing Deck Boards

A wood deck with a measuring tape and a work boot in the corner.

With the joists in place, you can start laying out the deck boards. Start in the middle of the deck and make sure the board hangs off each side of the deck. Screw in the board in each location that it meets a joist. Make sure to space out the next board—a nail or piece of scrap wood works great for this purpose—and continue the process until the joists are properly covered. If the deck boards are too short, then stagger the boards along the seam for better structural integrity.

Step 8 - Finishing Touches

Once the deck boards are in place, it’s time to trim off the overhang. To accomplish this, simply mark a straight line on the outer edge of the joists using a chalk line and cut. Use a long deck board as a face frame to conceal the concrete blocks and complete the look of a floating deck. Depending on the type of deck boards used, you may need to stain them. If you have to stain the boards, it is easier to stain them prior to installing them onto the joist boards.