How to Build a DIY Floating Deck: A Beginner-Friendly Weekend Project

Differences Between a Floating Deck and a Traditional Deck

A floating deck is the perfect way to start your decking journey without having to deal with all the complexities of other forms of deck construction. Unlike the more conventional form of decking, which relies upon a solid connection to either permanent foundations or an existing structure, a floating deck rests on a series of concrete piers laid directly on the ground.

Why Beginners and Renters Choose Floating Decks

A number of factors contribute to why floating decks are so popular among new home builders and temporary or rental living arrangements:

• Floating decks require simple foundation work compared to the deep footings required for a traditional deck
• Design tolerances on floating decks allow for some error in measuring dimensions (i.e., floating decks do not need to be built to the same tolerance as a traditional deck)
• Modular construction allows you to build a floating deck at your own pace
• You will need fewer tools to build a floating deck than would be needed to build a traditional deck.
• You can purchase the basic tools needed to build a floating deck (e.g., hammer, tape measure)
• You can avoid investing in the expensive, specialized equipment required to build a traditional deck.

Many renters can enjoy the benefits of floating decks because they can be removed and relocated. Once a traditional deck is installed, it becomes an improvement to the rented property, making it difficult for the tenant to remove it after they move. In addition, many landlords are willing to accept floating decks into their rental properties more quickly than they would accept traditional decks, since floating decks do not damage or alter the permanent structure of the house.

Since floating decks are considered temporary installations, they should not increase a property's value. Therefore, floating decks offer budget-conscious homeowners and renters the opportunity to create outdoor spaces without creating long-term financial obligations.

With proper care and maintenance, floating decks can last up to 15 to 20 years. While this may seem comparable to traditional decks, the cost to build a floating deck is considerably lower. Modern concrete deck blocks feature notched designs that provide effective support for beams and joists by securing them in place.

Layout Planning Steps

Your deck is an extension of your home, so choosing a size and shape for your floating deck will have to take into account how much room you have in your yard, as well as what you want to do with it.

Decide on a Shape and Size

Take accurate measurements of the space and note anything that could impede the design of a floating deck (such as tree roots, underground utilities, property lines, etc.).

Newcomers will likely begin with rectangular or square designs measuring less than 200 square feet. The 8’ × 10’ area will be adequate to hold a small dining table with four chairs. A 12’ × 12’ decking area is large enough to accommodate larger pieces of furniture and/or other deck features.

When determining how large to build your decking project, you need to consider your joist spacing. 16” apart is standard and will provide good stability to your decking project. Building your decking project at 12” apart will add even more strength and support in an area where there will be heavy usage. However, building a decking project using a 24” spacing is not recommended in an area that has high traffic, as it may create a bouncy and unstable condition on the decking.

Consider Sun Exposure and Drainage

How you place your deck will greatly affect its comfort and usability throughout the day. Sunlight exposure varies dramatically depending on where the deck is located and its orientation. Decks that face south get the most direct sunlight every month of the year. The other side of the coin is decks that face north; these areas remain shaded for the majority of the time.

Decks located east have a nice morning sun and can be very pleasant. On the flip side, decks that face west receive intense afternoon sun. Proper drainage is also crucial to extending the life of your deck and preventing water damage. To ensure proper drainage, your site should have a slight slope (about 1/4 inch per foot) away from the building(s). There should also be a ½-inch gap between decking boards to provide adequate drainage space.

When installing deck blocks, they should sit on 2-3 inches of compacted gravel rather than directly on the ground. This helps prevent deck blocks from shifting due to freeze-thaw cycles and improves drainage beneath the deck.

Use Free Online Deck Design Tools

Multiple online tools will let you see what your deck will look like before purchasing any materials.

• SketchUp is a 3D tool with a very user-friendly interface
• Deck Designer estimates of all the materials needed are provided in addition to your designs
• Lowe's Deck Designer provides a list of all the materials you need to buy based on your designs
• Home Depot Deck Planner has pre-built designs that you can customize to fit your needs

For simple designs, graph paper is also an effective tool. Use one square per foot when using graph paper, so you have a reference point to measure your design and accurately estimate material costs.

Tools and Materials Checklist

Planning ahead with the right tools and materials will make all the difference between a successful weekend build and an ongoing battle.

Essential Tools for Weekend Construction

Most float decks can be completed using standard woodworking tools that many homeowners have on hand. This will help minimize your purchase price for the remaining required tools.

Lumber Selection and Sizing

The selection of lumber will also affect how the deck looks, how much you have to maintain it, and its overall life expectancy.

Standard floating deck construction requires:

• Posts at corners with 4 x 4 lumber
• Joist material: 2 x 6 or 2 x 8 lumber (depending upon span)
• Rim joist material: 2 x 8 or 2 x 10 lumber
• Decking surface: 2 x 6 or 5/4 x 6 lumber

Hardware and Fasteners

High-quality hardware will help ensure your deck stays firm and long-lasting. Spend money on corrosion-resistant materials to avoid early failure from corrosion.

Galvanized or stainless steel should be used exclusively as fasteners. Due to the corrosive effects of salt air on standard materials, stainless steel fasteners are required in coastal areas.

Step-by-Step Build Process

The construction process will be divided into five phases, which you will generally complete over a weekend. The five phases are sequential, as each phase is dependent upon the completion of the previous phase and will create a solid base for your floating deck.

1. Prepare the Ground and Layout

Remove grass, weeds, and rock debris from the area where you have designated your floating deck. Roughly level the area so it slopes slightly (about 1/4 inch per foot) away from structures such as houses to ensure proper drainage. Outline your floating deck using string and stakes by referencing your deck plans.

Apply a layer of landscaping material (such as landscape fabric) over the leveled and cleaned area to inhibit weed growth underneath your completed floating deck.

2. Set Deck Blocks in Place

Set concrete deck blocks at corners and at regular intervals based on the overall dimensions of your floating deck. Create shallow holes for each block and fill each hole with 2-3 inches of gravel to aid in drainage. Level each individual block. Once all the blocks are set, verify that they all line up using a long level or a string line.

3. Build and Square the Frame

To build the outer framing of your box, use 2×8 or 2×10 pressure-treated wood. When connecting the two ends of each piece at a corner, use a galvanized bracket. To ensure your frame is square, measure both diagonals from one end to the other. The measurement for both diagonals should be exactly the same.

4. Add Joists and Support Beams

Install your interior joists spaced 16 inches on center. From the center of one joist to the center of the other. Use a joist hanger to attach each joist to the rim board. On larger decks, you will need to add vertical support beams every 6-8 feet in addition to your horizontal joists. Verify that all of your joists are level from end to end. If any of your deck blocks have become out of level during the framing process, add shims as necessary.

5. Install Decking Boards

Install decking boards parallel to each other across the joists. Space boards 1/4 inch apart for water flow and 1/8 inch at each end for expansion. Fasten each board with two #10 x 1-1/2" deck screws at every joist crossing.

Begin installing decking boards at both ends of the decking area and work toward the middle, checking frequently to ensure alignment. Use a circular saw to trim decking boards that extend beyond the edge of the decking area, creating clean, finished edges.

Finishing Touches

Once you have completed the structural elements of your floating deck, there are additional details to finish that will enhance both its aesthetic appeal and user safety. The following steps will help you turn a simple flat surface into an attractive, safe outdoor space, which is what many users want in their floating deck.

Sand Rough Edges and Corners

First, use 80-grit sandpaper to sand all rough-cut edges and corners. Then, use 120-grit sandpaper for the final pass to provide a smooth finish. Be sure to pay special attention to the ends of decking boards and all other spots that could potentially create a splinter. For large decks, a palm sander can speed up the process.

Add Railings or Steps if Needed

Railings on decks that are 24 inches or more above grade are required. Railing height should be at least 36 inches. Baluster spacing is also limited (less than 4 inches) to prevent small children from being able to slip through. Steps need to have standard measurements as well: the maximum riser height allowed is 7.75 inches. The minimum tread depth for each step is 10 inches.

Inspect for Stability and Safety

Before using your deck, perform a comprehensive inspection to help ensure it is safe:

• Look for exposed nails and screws on both the underside of the decking and the top surface
• Push down firmly on each railing to check whether they are securely fastened to the frame
• Check that the decking blocks are still at the proper height and securely in place
• Walk across the decking to check whether any boards flex excessively

Set up a semi-annual inspection schedule to keep your deck structurally sound and extend the time you can enjoy it.

Conclusion

Proper planning is important to ensure you're successful with your project. Selecting appropriate dimensions for your deck, considering how much sunlight it will receive, and choosing the material you use all help prevent costly mistakes before and/or after building your deck. Your deck's build process can be divided into five phases: ground preparation, placing the blocks, framing the deck, installing the joists, and finally adding decking.

A finished floating deck can add multiple functions to an area outside your home. A floating deck usually pays back at least the majority of the money spent on it when you sell your house due to the increased value of your property. In addition, a properly built floating deck will provide many years of use. To extend the life of your floating deck, it should be inspected regularly for damage or needed repairs to ensure it is safe and attractive.

You may want to consider a floating deck if you need a temporary or semi-permanent solution. Since a floating deck can be easily modified, expanded, or relocated, it is great for transforming outdoor spaces.

There are many rewards associated with finishing this project. Beyond having created a new outdoor area made just for you, you will also have learned some useful carpentry skills that you can apply to future projects. With proper care, your floating deck will remain available to you for years and serve as a base for additional outdoor projects.