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Building A Floating Deck Over Concrete Slab

Are you tired of staring at your dull, gray concrete slab in the backyard? It’s time to transform that space into a stunning floating deck that you can enjoy all year round.

Building a floating deck over a concrete slab may seem daunting, but with the right tools and materials, it’s an achievable DIY project that will bring new life to your outdoor living space.

First, you’ll need to assess the feasibility of your project. Check the condition of your concrete slab and make sure it’s sturdy enough to support the weight of a deck.

Then, gather all the necessary materials and tools, including lumber, screws, a circular saw, a drill, and a level. With these in hand, you’re ready to begin the process of measuring and marking your slab, building a frame, installing joists and beams, laying decking material, and adding railings and stairs.

Once your deck is complete, you’ll need to waterproof and seal it to protect it from the elements. With proper maintenance, your new floating deck will provide you with a beautiful and functional outdoor space for years to come.

Assessing the Feasibility of Your Project

Before you start, it’s important to figure out if your project is doable. Assessing the feasibility of building a floating deck over a concrete slab involves several factors.

Firstly, you need to ensure that the concrete slab is level and stable. If the slab isn’t level, you’ll need to level it to avoid potential safety hazards. Additionally, if the slab isn’t stable, it may not support the weight of the floating deck.

Secondly, you need to consider the size and shape of the concrete slab. If the concrete slab is too small or irregularly shaped, it may be difficult to build a floating deck that fits properly. You may need to adjust the size and shape of the deck to fit the dimensions of the slab. Alternatively, you could choose to build a smaller deck or consider other options, such as a patio or pergola.

Lastly, you need to determine if building a floating deck over a concrete slab is within your skill level and budget. If you’re not experienced in carpentry or construction, you may need to hire a professional to help you with the project. Additionally, building a floating deck can be expensive, so you’ll need to budget accordingly and consider alternative options if necessary.

By assessing these factors, you can determine if building a floating deck over a concrete slab is the right choice for you.

Gathering Materials and Tools

We’ll need to grab some wood, screws, a saw, a drill, and a level to get started. The type of wood you choose is important and will depend on your location and budget. Pressure-treated lumber is a popular choice for its durability and resistance to rot and insects. Cedar and redwood are also good options, but they can be more expensive. Make sure to choose wood that’s rated for outdoor use.

Along with the wood, you’ll need screws to attach it to the concrete slab. Tapcon screws are specifically designed for this purpose and are a popular choice. You’ll also need a saw to cut the wood to the appropriate length and a drill to make holes for the screws. A level is essential to ensure that your deck is level and even. You may also need additional tools depending on the specifics of your project.

Gathering the right materials and tools is essential to the success of your project. Take the time to research and choose the best materials for your location and budget. Make sure you have all the necessary tools and equipment before you begin. With the right materials and tools, you’ll be one step closer to building a beautiful floating deck over your concrete slab.

Measuring and Marking Your Concrete Slab

Now it’s time for you to measure and mark your sturdy foundation with precision, ensuring a level and stable base for your new outdoor oasis. Begin by measuring the length and width of your concrete slab using a tape measure. Make sure to record these measurements accurately as they’ll determine the size of your deck.

Next, mark the center point of each side of the slab using a chalk line or marking paint. This will help you accurately place the ledger board, which’ll be the main support for your deck.

Once you have marked the center points, measure and mark the location for your ledger board. This board will be attached to the concrete slab using concrete anchors. It’s important to ensure that it’s level and properly aligned with the markings on the slab. Use a level to ensure that the ledger board is straight and adjust as necessary.

Once you’re satisfied with the placement of the ledger board, mark the location of the anchors and drill holes into the concrete slab using a hammer drill.

Finally, double-check all of your measurements and markings before proceeding with the next step. Any errors at this stage could lead to an unstable and unsafe deck. Take your time and make sure that everything is level, straight, and properly aligned.

Once you’re confident in your markings, you’re ready to move on to the next step in building your floating deck over your concrete slab.

Building a Frame for Your Deck

To construct a sturdy and level base for your outdoor oasis, you should begin by framing your foundation with precise measurements and accurate markings. The frame serves as the support structure for your deck, ensuring that it’s stable and can withstand the weight of people and furniture.

When building your frame, it’s crucial to use pressure-treated lumber that can withstand exposure to the elements. Use galvanized metal brackets and fasteners to secure the frame to the concrete slab, ensuring that it’s level and square. Take your time when building the frame, double-checking your measurements and making any necessary adjustments to ensure that it’s perfectly square and level.

Once you’ve completed the frame, it’s time to add the joists. Joists are the horizontal supports that run perpendicular to the frame and provide the structure for your decking boards. Use metal joist hangers to attach the joists to the frame, spacing them out evenly. Make sure that the joists are level and that they’re attached securely to the frame.

With the frame and joists in place, you’re now ready to move on to the next step in building your floating deck over a concrete slab.

Installing Joists and Beams

Upon completing the frame, the next step involves the precise installation of the horizontal joists and support beams. This is the crucial stage that requires attention to detail and accuracy.

Here are the steps to follow when installing joists and beams:

  1. Measure and mark the spacing for the joists on the frame. The recommended spacing is 16 inches apart, but you can adjust depending on the size of your deck boards.

  2. Install the beams perpendicular to the joists. Attach the beams to the frame using metal brackets. Ensure that the beams are level and sturdy.

  3. Install the joists on top of the beams, making sure that they are perpendicular to the beams. Secure the joists to the beams using metal hangers.

  4. Double-check the level of the beams and joists. Use a spirit level to ensure that everything is even and straight. Make any necessary adjustments before proceeding to the next stage.

Once you have successfully installed the joists and beams, you’re ready to move on to the next step of building your floating deck. Remember to take your time and be thorough in your work to ensure that your deck is stable and safe to use.

Laying Your Decking Material

You’re ready to transform your outdoor space into a beautiful oasis by laying down the perfect decking material that will have you feeling proud and excited to show off your new space to friends and family.

Before you start, make sure to measure and cut your boards to fit the size of your deck. Next, lay down your first board, ensuring that it is straight and flush with the edge of your deck. Use decking screws to secure the board in place.

Continue laying down your decking material, making sure to leave a small gap between each board for expansion. Use a chalk line to ensure that your boards are straight, and a square to ensure that they are flush with the edge of your deck. As you lay down each board, use a level to ensure that it is even with the previous board.

If you encounter any obstacles, such as a post or a drain, use a jigsaw to cut the board to fit around it.

Once you have laid down all of your decking material, it’s time to finish the edges. Use a circular saw to trim any excess boards, making sure that they are flush with the edge of your deck. To create a clean and polished look, consider adding trim boards around the edges of your deck.

Finally, give your deck a thorough sweep to remove any debris. You’re now ready to enjoy your new outdoor space!

Adding Railings and Stairs

Now it’s time to make your deck safer and more accessible by adding railings and stairs, giving your oasis a stylish and functional upgrade.

First, decide on the railing style that best fits your deck’s aesthetic and your personal preferences. Some popular options include wooden railings, metal railings, and cable railings. Make sure to check local building codes to ensure your railings meet safety standards.

To install the railings, begin by measuring the distance between each post and cutting the railing material to fit. Attach the railing posts to the deck using sturdy brackets and screws. Then, attach the railing sections to the posts using appropriate hardware. If necessary, add decorative post caps or finials for a finishing touch.

Once your railings are in place, it’s time to add stairs to your deck. Determine the best location for your stairs and measure the height and depth of each step. Cut stair stringers to fit and attach them to the deck using metal brackets. Install the stair treads and risers, making sure they are securely fastened.

Finally, add handrails to the stairs for added safety and support. With your railings and stairs installed, your floating deck is now a safe and stylish outdoor oasis.

Waterproofing and Sealing Your Deck

It’s time to make sure your outdoor oasis can withstand the elements by waterproofing and sealing it, giving your deck a longer lifespan. After all the hard work you’ve put into building your floating deck over a concrete slab, you don’t want it to rot or warp due to moisture. Here are some tips to protect your investment:

  • Choose the right product: There are many waterproofing and sealing products available in the market, but not all of them are suitable for your deck. Make sure to select a product that is designed for your specific decking material and climate.

  • Follow the instructions carefully: To get the best results, it’s important to follow the manufacturer’s instructions for application, drying time, and maintenance. Don’t rush the process or skip any steps, as this may compromise the effectiveness of the product.

  • Keep up with maintenance: Even with the best waterproofing and sealing, your deck still needs regular maintenance to keep it in top shape. This includes cleaning it regularly, removing any debris, and reapplying the product as needed.

By taking these steps, you can ensure that your floating deck over a concrete slab will look great and last for years to come. A well-maintained deck not only adds value to your home, but also provides a relaxing space for you and your loved ones to enjoy the great outdoors. So, take care of your deck, and it’ll take care of you!

Maintaining Your Floating Deck

Don’t let neglect ruin your outdoor haven – keep up with regular maintenance to ensure your floating deck stays beautiful and functional for years to come.

One of the most important things you can do is to inspect your deck regularly for any signs of damage or wear. Check for loose or damaged boards, as well as any signs of rot or mold. If you do notice any issues, address them as soon as possible to prevent further damage.

Another key aspect of maintaining your floating deck is cleaning it regularly. Dirt, debris, and even leaves can accumulate on your deck, leading to staining and deterioration if left unchecked. Use a broom or leaf blower to remove any loose debris, and then use a power washer or a deck cleaner to thoroughly clean the surface. Regular cleaning can help prevent the need for more extensive repairs down the line.

Finally, consider applying a protective coating or sealant to your deck to keep it looking and functioning its best. A high-quality sealant can help protect your deck from water damage, fading, and other types of wear and tear. Be sure to follow the manufacturer’s instructions for application, and reapply as needed to keep your deck in top condition.

With regular maintenance and care, your floating deck can serve as a beautiful and functional addition to your outdoor space for years to come.


Congratulations! You’ve successfully built a floating deck over your concrete slab.

Now that your deck is complete, it’s important to maintain it properly. Regular maintenance will ensure that your deck lasts for years to come.

To maintain your deck, start by cleaning it regularly to remove dirt and debris. You can also use a power washer to remove stubborn stains.

Check for any signs of damage, such as rotting or warping, and repair them immediately. Finally, apply a fresh coat of sealer every few years to protect your deck from the elements.

By following these maintenance tips, you can enjoy your beautiful new deck for many years to come. So sit back, relax, and enjoy the fruits of your hard work!