Floating Deck DIY: Step-by-Step Instructions

Embarking on a DIY project to install a floating deck in your backyard? You're in the right place! This guide will walk you through every step, ensuring you build a sturdy, safe, and stylish deck that floats your boat – literally.

Before you start, gather the right tools and materials: pressure-treated lumber, screws, joist hangers, ledger board, post Anchor bolts, gravel, and concrete. Don't forget safety gear: gloves, safety glasses, and ear protection. Now, let's dive into the building process.

Deck Foundation and Footings

The first step is to create a solid base for your floating deck. This involves building footings that will support the entire structure.

Mark out the locations for your footings – they should be at least 6" deep into undisturbed soil. Use a post hole digger to create the holes, ensuring they're square and uniform in size. Fill the holes with a mix of gravel and concrete, using a 3:1 ratio.

Installing the Ledger Board

The ledger board is the horizontal board that attaches the deck to your house. It's crucial for the stability of your deck, so ensure it's level and properly attached to the house band joist.

Mark the location of the ledger board, then use a level to ensure it's perfectly horizontal. Attach it to the house band joist using lag screws or coach screws, ensuring they're long enough to grip into the joist. Use a drill driver for a clean, tight fit.

Setting Posts and Installing Post Anchors

Deck posts are the vertical beams that support the weight of the deck. Ensure they're square, level, and plumb for a stable structure.

Set your posts into the footings, using post anchors to attach them securely. The top of the post should be level with the ledger board. Use a level and a Carpenter's square to ensure perfect alignment. Once set, fill the post holes with concrete and allow it to cure.

Building the Deck Frame

Now that you have a solid foundation, it's time to build the frame of your floating deck.

Attach joist hangers to the ledger board and posts, ensuring they're level and spaced evenly. The hangers should be set back from the outer edge of the post to allow for a fascia board later on.

Installing Joists and Beams

Joists are the horizontal boards that span the width of the deck, providing support for the decking boards. Install them into the joist hangers, ensuring they're level and square.

For larger decks, you may need to install beams to support the joists. These are placed perpendicular to the joists, usually at the midspan of longer joists. Attach them using joist hangers or by notching the joists and using Carpenter's glue and screws.

Sistering Joists

If your deck is large or you're using wider decking boards, you may need to sister – or double – the joists for added support.

Place a second joist next to the existing one, aligning them perfectly. Attach them together using screws or wood glue, ensuring they overlap by at least 12". This will distribute the weight of the deck more evenly.

Installing Decking Boards

The final step is to install the decking boards. Choose a durable, weather-resistant material like cedar or composite.

Start at one end of the deck, laying the first board tightly against the framing. Use a 4" or 5" gap between each board for water drainage. Secure the board with hidden decking screws or nails, ensuring they're below the surface for a smooth look.

Adding Railings and Stairs

For safety, consider adding railings around the perimeter of your deck. Build them according to local building codes, ensuring they're at least 36" tall.

If your deck is more than 30" off the ground, you'll need to build stairs. Ensure they're evenly spaced, with a consistent rise and run, following local building codes.

Congratulations! Your floating deck is now complete. Enjoy your new outdoor space, knowing you've built something strong, safe, and stylish. Regular maintenance will ensure it stays in top condition for years to come. Happy building!