How Far Apart Should Deck Posts Be?

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how far apart should deck posts be

Installing a deck is a great way to increase your home’s value and usable space. 

A well-built deck will last for many years and give you the service you need. However, if you don’t build your deck properly, you could be facing a lot of maintenance and repairs. 

Understanding how far apart deck posts should be can help you design the perfect plan. 

By taking the time to make sure your deck is supported, you can be sure it will be safe. This is especially important with floating decks, which need to be as secure as possible. 

In this article, we have laid out everything you need to know about deck post spacing. This will help ensure that you have no issues going forward and can enjoy your new deck. 

Deck Post Spacing: Basic Idea

Many factors will determine how far apart your deck posts should be. There is no catch-all answer and it will depend on your plan and what your deck is like. 

The things that will influence your deck post spacing include: 

  • Design of your deck
  • Height of your deck
  • Your local building codes
  • Size of the deck beams 

Why Do Deck Posts Need to Be Properly Laid Out?

why do deck posts need to be properly laid out

Your deck posts need to be properly laid out because they are going to be supporting the weight. Since the posts hold the deck up, they need to have the right weight distribution. 

If you don’t lay out your posts correctly, you could end up with sagging. 

This is especially true for floating decks but also needs to be done with platform decks. Even if your deck is attached to the house, the posts will still hold most of the weight. 

If you plan on having a hot tub or other features, post spacing is even more important. Making sure that your deck is properly supported will keep it in better shape for much longer. 

Deck Design 

Simpler deck designs will most likely need fewer posts. 

If you have a complicated design with a lot of outcroppings and other features, you will need more posts. That is because every part of the deck that uses other beams needs to be supported. 

A simple square or rectangle deck design will need posts every 8 feet. As long as you observe this rule, you should be in compliance with codes and safe. 

If your deck is in a circle or has curved outcroppings, you will most likely need more posts. If you have never built a deck before, it is best to keep it as simple as possible. 

Deck Height 

If your deck is going to have more height to it, you will want to have more posts. 

This is because there will be more pressure on each individual post. Holding the deck upright will become more stressful and it will be difficult for each post to hold it. 

If your deck is more than 5 feet high, you will not want to use 4×4 posts. Instead, use 6×6 posts as these can withstand greater pressure and will hold up for longer. 

Check with your local building codes to see what they dictate as far as spacing for raised decks. 

Building Codes

building codes

Building codes will have a lot to do with how many posts you will need for your deck. 

Every county and municipality has its own rules regarding decks and how they are designed. If you are unfamiliar with your local codes, it is best to check with them before construction. 

This is one of the reasons that hiring a professional may be your best bet when building a deck. They will be able to make sure that everything complies with local codes. 

For the most part, deck posts need to be, at most, 8 feet apart. However, this may change depending on things like soil, weather, and other location characteristics. 

Deck Beam Size 

The size of your deck beams will determine how many posts you need to have. 

The thinner the beams are, the more likely they will be to flex. This means that you should have more post support to hold them up. 

For example, if you are using 2x8s for beams, your posts should be about 7 feet apart. However, if you are using 2x10s, they can be 9 feet apart. 

Check with a deck designer before finalizing your design to make sure you will have enough support. 

Frequently Asked Questions

faq how far apart should deck posts be

Should I concrete my deck posts?

Whether or not you should concrete your deck posts will depend on the soil they are sitting in. However, it is almost always recommended that you should do this. 

This will help prevent the posts from deteriorating and keep them in place if the ground shifts. 

How long will pressure-treated posts last in the ground?

Pressure-treated posts are perfect for decking posts since they are weather-resistant. If they are properly cared for, pressure-treated posts should last up to 25 years. 

How long these posts last will depend on things like weather and soil condition. 

How many bags of concrete does it take to fill a post hole?

For the most part, it should take between 1 and 4 bags of concrete to fill a post hole. However, this will depend on the depth and width of the hole. 

It is always a good idea to get more concrete than you think you will need. 


Building a deck can be incredibly rewarding and greatly improve your home. Making sure it is secure will give you the peace of mind you need. 

By understanding what factors go into post spacing, you can be sure your deck is safe. 

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Michael J. O’Connor is a writer and marketing specialist from the Bay Area of California. A graduate of Sonoma State’s Creative Writing program, he spent many years as a contractor and carpet layer, learning the ins and outs of flooring and general contracting. When he’s not typing away at his desk, he enjoys hiking with his dogs, woodworking and collecting rare books. See full biography here.

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