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Part 1: Preparation for Building a Freestanding Deck

August 04, 2025

Outdoor decks are not always attached to a building. Freestanding decks are often used as viewing platforms or a secret place to read a book or relax after a long day at work. You may not know how to build a freestanding deck, but it’s no different than a regular deck. When making a freestanding floating deck or independent deck, it is important that the supporting feet do not move around. Other than that, it’s pretty simple.

What Is a Freestanding Deck?

A freestanding deck is a self-supporting outdoor structure that is independent of a house or other structure. Unlike decks attached to a building, freestanding decks are usually located in a different area of the house and can create versatile outdoor living spaces.

Instead of relying on the structural support of the house, these decks are supported by their own foundations, often using columns and beams. Freestanding decks are flexible in design and can be placed in scenic or uneven terrain. They can serve as a stand-alone retreat, providing a separate, dedicated space for relaxing, dining, or entertaining.

The design possibilities for freestanding decks are vast, making them a popular choice for homeowners looking to enhance their outdoor living experience.

Why Build a Freestanding Deck?

Because houses have cantilevered arms or brick veneers, some decks cannot be attached directly to the house with dividers. For example, when building a home with stucco walls, many builders prefer to build a separate deck rather than cut and flash stucco because it can be messy and difficult to maneuver.

The walls of some older homes may not have been built with enough care, and therefore may not be strong enough to support an additional deck. These decks can stand on their own by simply adding an extra beam and post next to the walls of the house.

To prevent these decks from sinking, it is necessary to place these frost-proof footings on top of filled-in dirt. When building a new house, the soil around the footings is often unstable because it is backfilled. It may be necessary to place these anti-freeze footings under the base of the house.

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Considerations Before Building a Freestanding Deck

Structural Design

Freestanding decks that are more than 2 feet off the ground must have diagonal bracing to prevent the deck from moving side to side or laterally. Since one end of a freestanding deck is not attached to the house, uplift and support are bigger issues to consider in structural design.

4×4 bolts bolted at a 45-degree angle between the support posts and the beams will prevent the deck from moving parallel to the house. Many people use these braces to support the corner posts and the rest of the fence. From the top of the corner post to the bottom of the next closest fence post, you will see a diagonal brace. This needs to be done on both sides of each individual corner of the deck.

Laying diagonal deck boards and sway braces under the joists will reduce the support. Strong winds can lift a freestanding deck off the ground, but buried support posts can help support the deck. But wood-eating bugs can burrow into hidden posts. Structural hardware can be used to connect the concrete footings to the deck posts above ground. The purpose of this hardware is to resist uplift forces.

A registered residential structural engineer should design any freestanding deck that is more than 4 feet off the ground. Videos of deck collapses are all over the Internet, and the risk of this happening is real. An expert can teach you how to build a safe structure that will prevent an independent deck from collapsing. Paying a structural engineer for advice is the best money you will ever spend on this job.

Start with The Zoning Department

Before hiring a structural engineer to create a plan for your structure, you should make sure you can build the deck. Many towns have strict zoning regulations that dictate what you can build and how far the deck is from the property line.

Communicating with zoning officials is easy. You just need to make sure you get a written copy of the zoning regulations that state you can build a deck. The building code will tell you the size of your new deck.

If you can’t meet the zoning regulations, you can apply for a zoning variance so you can build the deck. Keep in mind that a zoning variance is usually only granted if you can prove that complying with the zoning rules is too difficult for you.

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Obtaining a Building Permit

Building permits are required for all types of decks. In order to obtain a permit, you’ll need to show a floor plan for your deck, and you may even need a floor plan. Contact your city’s building department personnel to find out what drawings are required to obtain a permit.

Before spending a lot of time and money on this part of the process, make sure your new deck is large enough for your needs. In order to have enough room for a table and chairs that can seat four people, your new deck must be at least 12 feet by 12 feet. This will allow you to walk around the table as people sit down.

It’s a good idea to get a feel for the design options you want for your deck first. Make a note of the dimensions of your favorite outdoor decks and use those dimensions as a guide for your plan.

The Base of a Freestanding Deck

The base of a deck consists of freestanding deck feet. Most decks are supported by just six or eight 6×6-foot posts, which means that the entire weight of the deck is concentrated on these posts. When filled with people and furniture, the average outdoor deck can weigh several tons.

For this reason, outdoor deck footings usually need to be at least 2 feet wide. Have a structural expert specify the diameter and thickness of the concrete footings so the deck doesn’t sink into the ground.

Frost Levels Matter

You may live in an area where the ground freezes in the winter. In these places, the ground beneath the deck footings must be below the frost level. Some parts of the United States can have frost depths of more than six feet!

If the foundation is not below the frost level, the frozen ground will pull the entire deck up and put a lot of stress on the structural connections. Don’t skip this very important step. Local building inspectors almost always want to personally look at the footing bolt holes before pouring concrete to make sure they are deep enough.

To prevent the footings from sinking, these freeze-proof footings must be secured to the top of the fill. When a new home is built, the soil around the footings is often unstable because it is backfilled. These footings may need to be placed under the foundation of the home.

Freestanding Deck Framing

The most important thing to consider when planning a freestanding deck is the need for vertical bracing to prevent the deck from collapsing. If there are a lot of people dancing or walking around on the deck, the deck will start to rock back and forth. Don’t put the deck in danger of falling apart, especially if a lot of people are enjoying themselves on the deck.

Don’t underestimate the amount of deck support that needs to be set up under the deck joists. Installing beams from the top of one post to the bottom of the next post next to it will be the most important support. Again, the structural engineer will draw these supports and list the exact tools and materials needed to install them.

Finally, make sure there is a 2-inch space between the deck and the deck framing. This will ensure that debris does not get stuck in this area, which could damage the deck.

Deck Height

You may not think about how high your outdoor deck is, but it does matter. A deck-height surface that is 2 inches lower than the deck of the house will feel good. This way, water won’t come in under the doorway leading from the house to the deck.

If you have a choice of deck height, try to have it at least 7.5 inches higher than the poured platform at the bottom of the floor, patio, or steps leading up to the deck. Almost all engineers and experienced builders agree that steps with 7.5-inch risers and 10-inch treads are the most comfortable to walk up and down. In addition, they are very safe.

Summarize

As you embark on the exciting journey of building a freestanding deck, thorough preparation is the key to success. By taking the time to plan meticulously, adhering to local building codes, and gathering the right materials and tools, you set the foundation for a sturdy and beautiful outdoor space.

Prepping involves not just the physical aspects of construction but also a thoughtful consideration of your design, purpose, and how the deck integrates with your landscape. As you move forward, remember that safety is paramount, so take the necessary precautions during construction. With careful prepping, you’re not just building a deck. You’re creating a haven for relaxation, entertainment, and the enjoyment of the great outdoors.

FAQ

What is the 3/4/5 rule deck?

Mark 3 feet along one edge, starting at the corner. Next, measure and mark 4 feet along the edge next to the first. Take the diagonal that connects the two specified spots and measure its length. If your corner measures exactly 5 feet, it is square.

Is it necessary to install footings under a freestanding deck?

If the deck will be at ground level, it does not need footings for free-standing decks under certain conditions:

  • If the entire length of the girder is directly supported by the ground.
  • If the walking surface is 20 inches or less above the ground.

How far apart should posts be on a free-standing deck?

Posts should be spaced no more than 8 feet apart. Some builders place them every four feet to create a perfectly rigid structure. The maximum distance between footings is governed by the width of your joist material.

How do you support a freestanding deck?

Additional supports running parallel to the joists must be put on freestanding decks to avoid swaying. Typically, these braces are attached to the same joist as the post.

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Galen Content Writer
Galen is a content creator and decorator with five years of experience designing home decor. In his daily life, Galen is constantly on the lookout for the latest, great examples of house design and further optimizes his solutions. Additionally, he writes articles related to outdoor design, interior design, and architectural decorating materials to help brands build more engaging relationships with their audiences.
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