Want to build a deck without digging deep or pouring concrete? Wondering if you can actually pull off a stable, stylish deck that just sits on the ground?
In this post, you’ll learn exactly how to build a floating deck step-by-step—from layout to leveling to finishing touches.
By the end, you’ll know how to create a custom deck (or if hiring a professional deck installer is the better move).
What Is a Floating Deck?
A floating deck is a freestanding deck structure that is not attached to the house. Unlike an attached deck, which connects to the house through a ledger board fastened to the rim joist, a floating deck stands independently on its own footings or support blocks.
The “floating” name comes from the deck’s independence from the house structure, not from any literal floating. A well-built floating deck is as stable as an attached deck. The structural difference is that all loads (weight, wind, lateral) are carried by the deck’s own footings rather than shared between the deck framing and the house.
Why homeowners choose floating decks:
- No ledger attachment means no penetrations through the house’s exterior envelope — which eliminates the flashing and moisture management required at attached deck ledgers
- Permitting is often simpler for freestanding decks in some jurisdictions
- Grade-level floating decks can be built without railings (in most codes, no railing required under 30 inches of deck height)
- The deck can be positioned anywhere on the lot, not just adjacent to the house
How to Build a Floating Deck at a Glance
A floating deck is a ground-level platform that isn’t anchored deeply into the ground or attached to a house. Here’s a step-by-step overview of how to build one:
- Plan Your Size, Layout, and Location
- Mark and Level the Area
- Set Concrete Deck Blocks
- Install and Level Beams
- Attach Joists with Hangers
- Lay Down Landscape Fabric
- Install Decking Boards
- Add Finishing Touches
Contact us today about your deck installation.
1. Plan Your Size, Layout, and Location
Before you build a floating deck, pick the right place and make sure it’s sized to match your needs. A flat spot in your yard is easiest, but even a slightly sloped area can work if you’re willing to dig down a few inches and level it out.
You’ll want to avoid building too close to the house or over grass that stays damp.
Make sure there’s enough space for walkways, furniture, and any additions like stairs.
Common deck sizes include 8×12 or 10×12, but your deck layout can be customized to fit the space you have.
Always check whether you’ll need permits to build a floating deck. Some cities have height or framing rules, especially in areas with a frost line that could shift the deck over time.
2. Mark and Level the Area
Start by outlining your deck area with string and stakes.
Keep the corners square by measuring diagonally from opposing corners—your lines should match up within about 1/4 inch.
Next, mark where the deck blocks will go. Most builders use a grid with 4-foot spacing between blocks.
Dig out each point about 4 to 6 inches deep and fill the bottom of each hole with compacted paver base to prevent settling. The goal is to get the blocks level with one another, even if your ground is uneven.
You might have to add or remove a bit of gravel or sand under certain blocks to get everything sitting evenly.
3. Set Concrete Deck Blocks
With your layout prepped, it’s time to set the deck blocks.
These will act as your concrete footings, holding up the rest of the structure without being anchored into the ground.
Start at the highest point in the yard, placing the first block. From there, work outward, making sure all the blocks are level with each other.
Use composite shims for any minor height adjustments. These can help you get the beams and frame perfectly flat without having to redo the base.
Remember: even a difference of a few inches between one corner and another can throw the whole deck off. Double-check the level as you go.
4. Install and Level Beams
Once all the blocks are set, lay your beams across the top.
These long boards, usually treated lumber, form the base that supports the joists and deck boards.
If needed, cut 4×4 posts to sit in the blocks and raise the beams to your desired height. Attach them with framing anchors or screws rated for exterior use. Make sure your beams are level across the span and sit flat on the blocks so there’s no rocking or wobbling.
This is the foundation for the entire frame, so take your time getting this part solid.
5. Attach Joists with Hangers
Now it’s time to build the main deck frame.
Start by constructing the outer frame with pressure-treated 2×6 boards and deck screws. Double-check that the frame is square and sits snugly on the beams.
Install joists every 16 inches using joist hangers. These metal brackets hold each joist securely and keep spacing consistent. You may need to measure and cut each joist individually, especially if your deck blocks aren’t spaced perfectly.
The tighter and more even your joists, the easier it will be to install the deck boards later on.
6. Lay Down Landscape Fabric
Before you cover it all up, lay down landscape fabric to block weeds and keep moisture from collecting under your deck.
This step is easy to skip but pays off big over time.
Unroll the fabric across the whole ground-level area, overlapping seams by a few inches. Secure it with staples or garden pins so it stays in place while you build the rest.
Some people skip this step to save time or money, but once weeds start growing up through your deck boards, you’ll wish you hadn’t.
Is landscape fabric the best move, or is there another?
7. Install Decking Boards
Start at one edge and lay your decking boards perpendicular to the joists.
Whether you’re using pressure-treated wood or composite decking, space the deck boards slightly to allow for expansion and water drainage.
Secure the boards using exterior-rated deck screws. If you’re using composite materials, check whether pre-drilling is required—it depends on the brand.
Make sure each board runs past the outer frame slightly for a clean, finished edge.
You can also install a picture frame border if you want to cover the board ends and add a polished look.
Also Read: Deck Board Spacing: 1/8″ to 1/4″ and When to Use Each
8. Add Finishing Touches
Now that the structure is complete, you can customize your deck with extra details.
Trim boards around the outer edge to hide the joist ends and give the whole thing a more professional finish.
If your deck is raised slightly off the ground, stairs or a small landing might be a smart addition.
Some people even add built-in benches, planters, or lights to make the space feel like an outdoor room.
If your floating deck connects to an existing deck or walkway, now’s the time to make that tie-in look clean and seamless.
Need more inspiration? Check out these unique floating deck ideas.
The Illinois Frost Problem: What Every Belvidere Homeowner Needs to Know
This is the content that separates a Belvidere deck builder’s guide from a generic national DIY article. Most floating deck guides are written for warmer climates or don’t account for frost depth. Illinois has a frost depth of 42-48 inches in Boone County. That changes everything about how a “floating deck” should be built here.
The surface block problem:
The most common DIY floating deck method uses precast concrete deck blocks (Dek-Block, Bison Block, and similar products) placed directly on the ground surface. The deck framing rests on these blocks without any buried footing. This method works well in frost-free climates and is widely shown on YouTube and in national DIY guides.
In Belvidere, it doesn’t work long-term.
Northern Illinois’s freeze-thaw cycle causes soil to heave, the ground literally rises and falls as it freezes and thaws each winter. Surface-placed concrete blocks move with that soil. A floating deck built on surface blocks in Belvidere may be perfectly level at installation and noticeably unlevel by the following spring. After two or three winters, the deck frame has shifted enough to create visible slope, loose connections, and in some cases structural problems.
The correct approach for Belvidere:
A properly built ground-level “floating” deck in Boone County uses concrete footings poured below the frost depth, a minimum of 42 inches deep. These footings don’t move through freeze-thaw cycles because they extend below the frost line where soil movement doesn’t occur.
Below-frost footings eliminate the heaving problem but add cost and complexity over surface blocks. The result is a deck that stays level for decades rather than one that requires periodic shimming and releveling.
What this means for DIY:
Digging and pouring footings 42-48 inches deep requires either a rented power auger (difficult on solo projects) or a concrete contractor for the footing work. The footing excavation and pour is typically the most labor-intensive part of a proper ground-level deck in this climate. Many homeowners who plan to DIY a floating deck discover the footing work is the point where professional help makes sense.
Frequently Asked Questions
Do you need a permit for a floating deck in Illinois?
Sometimes. Many Illinois jurisdictions exempt a deck that’s under 200 sq ft, less than 30 inches above grade, freestanding, and not serving a doorway, which describes most floating decks. But Belvidere and Boone County set their own limits, so confirm before you build. A floating deck’s “no permit” appeal has real boundaries.
How big can a floating deck be without footings?
Most floating decks stay under about 200 sq ft and low to the ground, which is also where the common permit exemption sits. There’s no fixed engineering cap, but the larger and taller the deck, the more the deck-block base is prone to shifting and heaving, beyond roughly a single-level 12×16, dug footings or a permitted design become the safer choice.
How far apart should deck blocks be?
Typically 4 feet or less on center, but it depends on your beam and joist size and the decking you’re using. Closer spacing carries more weight and reduces sag. Always check the span against a joist/beam span table for your lumber, undersized spacing is the most common cause of a bouncy floating deck.
Will a floating deck heave in winter?
It can. This is the single biggest risk in Northern Illinois. The frost line here runs deep (about 42 inches), and because a floating deck sits on blocks above the frost line rather than on footings below it, the ground can lift the whole structure as it freezes and thaws. A well-drained, compacted gravel base under each block is what minimizes it. This is why the frost section on this page matters more here than in warmer states.
How long does a floating deck last?
It depends on materials: a pressure-treated floating deck lasts roughly 10–15 years, while composite decking on a well-built base can last 25 years or more. The base is the real lifespan driver, a floating deck built on poorly drained or un-compacted ground will shift and fail long before the boards wear out.
Hard Decks, Easy Living: Build Smarter with Us
If building your own floating deck feels a little out of reach, Hard Decks is ready to step in. We design and install custom decks across northeastern Illinois that are built to last—and look good doing it.
Let’s bring your outdoor vision to life. Fill out our contact form today or give us a call at +1 (815) 706-3325. You’ll be relaxing on your new deck before you know it.