How to Build a Floating Deck
Ground-level floating decks don't need footings, railings, or steps
A floating deck is built directly on the ground, either on gravel or on concrete blocks. This proximity to the ground makes a floating deck so easy to build.
Many areas don't require permits for decks below a certain height (such as 30 inches). And, because less material is required, floating decks are less expensive and can be built quickly, making them ideal for DIYers with limited experience.
What Is a Floating Deck?
Floating decks, sometimes called freestanding decks, rest on the ground and are not attached to any structure, including your house.
Before You Begin
A building permit is typically not required for a floating ground-level deck, but confirm this with your city's building department.
In many areas, a deck does not need a handrail or stairs if its walking surface is under 30 inches above the ground. However, it's best to keep a floating deck as low as possible to prevent even minor injuries.
Safety Considerations
If you need to dig the site for the deck, call 8-1-1, the national Call Before You Dig hotline, a free service that will mark all underground utility lines on your property.
Need more help? Talk to a deck & porch builder
What You'll Need
Equipment / Tools
- Shovel
- Rake
- Tape measure
- Carpenter's level
- Circular saw
- Drill and drill bits
Materials
- 9 4 x 8 x 16-inch concrete blocks
- 3-1/2-inch and 2-inch or 2 1/2-inch deck screws
- 10 Pressure-treated 2x8s (10 feet long)
- 2 Pressure-treated 2x8s (12 feet long)
- 22 Pressure-treated 5/4x6 or 2x6 decking boards (12 feet long)
- Landscape fabric and gravel (optional)
Instructions
Clear a flat area of lawn (or use a garage floor or driveway) for building the deck frame. If necessary, you can also build the deck on top of the concrete blocks.
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Prepare the Deck Area
Clear the ground where the deck will be installed. Remove grass and all other organic material, as needed. Rake the ground flat and level. Tamp it firmly with a hand tamp tool. If desired, lay down landscape fabric over the soil and add a layer of gravel to slow down weed growth under the deck.
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Set the Concrete Blocks
Arrange four concrete blocks in a rectangle so they are 12 feet apart along the long sides of the rectangle and 10 feet apart along the short sides. Measure from the centers of the blocks.
Position a block between each pair of corner blocks so they are evenly spaced.
Use a level to ensure all the blocks are level with one another. Add or remove gravel beneath blocks, as needed, to level the blocks.
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Build the Outer Frame
- Cut standard joists: Using a circular saw or power miter saw, cut 10 pressure-treated 2x8 boards to 117 inches. These will be the standard joists.
- Trim end joists: Measure the two 12-foot 2x8s and, if needed, trim them to exactly 144 inches These long joists will be the end joists.
- Dry-fit the deck: Place the two end joists over the ends of two standard joists to create a 120-inch-by-144-inch rectangle.
- Assemble the frame: Drill pilot holes, and fasten the pieces with three 3 1/2-inch deck screws at each corner. Measure from the inside of one corner of the frame and make a pair of marks every 16 inches along one of the 12-foot end joists. Repeat for the other end joist.
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Position and Square the Deck Frame
Place the deck frame onto the concrete blocks so the frame parts rest over the centers of the blocks. Measure diagonally between opposing corners. Square up the frame, as needed, by pushing diagonally from opposing corners (this takes two people). When the diagonal measurements are equal, the frame is square.
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Check the Blocks
Confirm that the deck frame is level and makes solid contact with each concrete block. If necessary, add or remove soil or gravel beneath blocks to adjust their height.
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Install the Remaining Joists
Install the six remaining standard joists, following the layout lines. Keep the standard joists flush with the tops of the end joists, as this ensures the deck boards will lie flat.
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Install the Deck Boards
Lay the 12-foot-long deck boards on top of the frame, with the boards perpendicular to the joists. Drill pilot holes, then fasten the deck board to the joists with deck screws. Continue installing deck boards, spacing them about 1/8 inch apart. With the circular saw, trim the ends of the deck boards so they are even.
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Finish the Deck
Wood decking boards should be finished with a protective deck stain or sealer when the wood is suitably dry. If left unfinished, the decking will turn gray and weather naturally. Deck boards can be painted, too, but paint wears off relatively quickly.
As long as the frame is constructed of pressure-treated wood, it does not need to be finished.
How to Choose Materials for a Floating Deck
You have several budget-friendly choices for the floating deck's frame and deck materials:
- Pressure-treated wood: Pressure-treated lumber is the least expensive and most durable option for the deck frame and decking boards.
- Southern yellow pine: For decking, an upgrade from pressure-treated wood is Southern yellow pine (SYP). This wood typically has fewer knots and a better appearance than standard pressure-treated decking.
- Cedar, redwood: Cedar and redwood are good choices for improving the deck's appearance. Despite their reputation for being naturally decay-resistant, they are not as rot-resistant as treated lumber.
- Composite: Composite decking is made from recycled plastic and wood pulp, and it is essentially rot-proof and requires no protective finish.
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What are the pros and cons of a floating deck?
The pros of a floating deck are that it is easy to build, safe, and usually does not require permits. It's also inexpensive since it uses less materials. On the downside, a floating deck may provide less property value than a permanent, attached deck.
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Will a floating deck add value to my home?
A well-built element such as a floating deck likely can add value to your home. But it provides less value than a permanent deck that's attached to your home.
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Is a floating deck stable?
A floating deck is stable because it is built no more than 30 inches above the ground. In some cases, the floating deck is even built directly on the ground on a bed of gravel.