Build a Floating Deck in Six Steps

Lead Image
  • 8-10 hours
  • Intermediate
  • 1,200-3,000
What You'll Need
Pre-cast concrete footings for each upright post
2x6-inch lumber for the outside of the frame and the decking
2x4-inch lumber for the stringing supports
4x4-inch lumber for the uprights
Stain or other wood preservative

If you are renting or plan to add to your existing structure, a floating deck may be the solution to creating a non-permanent backyard space. Instead of having to dig out footings and attach the deck directly to the home, you can easily install a beautiful deck that is separate from the main structure.


You will need to figure out the design of your floating deck before you can start building it. The most common and simple designs are obviously rectangles with dimensions customized to suit the space. Obviously, the more complicated you make your structure, the more experience you will have to have to build it.

Most floating decks require a vertical support every six feet in length, and one on each corner. Decide if you want to have a railing around the deck or steps. Depending on how high your deck is off the ground, local building codes might require both.

It is a good idea to put down the measured plans on paper and take that paper with you when you go to purchase your materials.


Most pre-cast footings have a metal bracket made for the 4x4 lumber built into them. Also, consider purchasing lumber that has been sealed or treated to prevent warping over time.

Step 1 – Build Frame

Build the main deck frame by using the 2x6 lumber for the outside, and 2x4 lumber for the interior supports. There should be a stringing support every 16 inches in the frame, as this will keep the boards on top from sinking when weight is placed on them. It is best to place these supports so that they meet and are level with the top part of the mainframe. Use 16d nails, deck screws, or bolts. Do not use drywall screws.

Step 2 – Place Pre-cast Supports

Lay the frame onto the area where you want the deck to go, put the pre-cast supports down at the four corners, and then mark them. You may need to dig out some of the placements to make sure that the frame will sit level when you are finished. The easiest way to check the even height of the pylons is to use a string level.

Place other supports at least every six feet, making sure that the location of the uprights will not conflict with the frame and its support stringers. The upright 4x4 lumber should fit just barely inside the perimeter of the mainframe.

Step 3 – Attach the Frame

Attach the uprights to the pre-cast, level pylons using lag bolts or deck screws.

Now you can lower the frame over the uprights. Attach it to the first pylon with screws. Then, go to each of the other three corners, checking the level at each post prior to screwing the frame to the upright.

Step 4 – Fasten Decking

Install the decking itself by cutting and screwing the 2x6 lumber on top of the frame, both to the stringers and the mainframe deck screws.

If you are going to have a railing, you may need to make cut-outs in the decking to allow the uprights to be higher than the deck itself.

Step 5 – Construct a Railing

Follow this step if you want to have a railing. Using the level string line, cut the vertical supports to the same even level. Start with the shortest vertical support, and mark off the others to the desired height. You can then top the uprights with more 2x6 material.

Step 6 – Stain or Finish

Spray or roll on a good seasonal wood finish. Follow the manufacturer's instructions for proper coating and drying time.