How Many Footings Do I Need for a Deck?

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how many footings do i need for a deck

When building a deck, it is very important that you consider safety. 

Having your deck be structurally sound is crucial to its longevity and security. This means taking the time to ensure that it is stable. 

In order for your deck to have a solid foundation, you need to install footings. 

Footings keep the deck secure in the ground and keep it from shifting. They are especially important in climates with a lot of moisture. 

Knowing how many footings you need for your deck can help you keep it strong and safe. 

In this article, we have laid out everything you need to know about deck footings. Using this information, you can build a deck that will last a long time and stay in place. 

Number of Footings for a Deck: Basic Idea 

The number of footings that you need for your deck will depend on a few factors. These factors include:

  • Size of the Deck 
  • Size of the Beams 
  • Size of the Footings 
  • Load Weight
By taking these factors into consideration, you can decide on the best number for your particular project. Getting this right will provide you with a solid foundation so your deck will be safe. 

Why Do You Need Footings for a Deck? 

why do you ned footings for a deck

Deck footings are usually made of concrete and are buried in the ground below the deck itself. 

They are meant to not only support the weight of the deck, but also the people on it. They do this by spreading the weight across the surface area of the footing. 

This keeps the posts that connect the footing and the deck from driving into the ground. 

Having your footings spread out will evenly distribute the load of the people and the deck. This way, no one footing will be bearing the weight of the entire load. 

If you live in an area that gets cold, frost is an important consideration. 

You will need to bury the footings below the frost line. This will prevent the concrete from decaying and becoming weak over time. 

Having enough footings will allow you to keep your deck safe and secure, even with a lot of people on it. 

Deck Size and Shape 

The size and shape of your deck will determine how many footings you need. 

A good rule of thumb is that you should never have footings more than eight feet apart. Your deck’s shape will have a lot to do with how many you’ll need to accomplish this. 

For example, if you have an 8×8 square deck, all you will need is four footings. One at each corner will be enough to support the entire thing. 

If your deck is square but larger than this, you can add more in the middle. However, they will need to be evenly spaced out. 

You can do this by triangulating them. This means measuring them from side to side as well as diagonally. 

Beam Size 

The size of the beams will also determine how many footings you need. 

No matter how large your beams are, you still shouldn’t go more than eight feet without a footing. However, if you are only using 2x6s, cutting that number in half is recommended. 

Many times, people will fasten together two 2” pieces of lumber to make beams. This will help you support the deck and keep the footings in place. 

Footing Size 

Footings will generally be between eight and 24 inches in diameter. 

The most common footing size, however, is 12 inches. This gives you enough space to spread out the load. 

The type of soil you are building on will affect your required footing size. 

Gravelly soils can usually support 3,000 pounds per square foot. Sand and clay soils can support around 1,500 pounds per square foot. 

The weaker the soil is under your deck, the larger your footings will have to be. 

This gives them a better surface area for the deck to sit on without collapsing underneath it.  

Deck Load 

You need to consider what you will be putting on your deck as well. 

If you are only going to have people on it, footings every eight feet is sufficient. 

However, if you are going to have things like hot tubs or furniture, more footings are recommended. If you aren’t sure, check with your local city building code to see what the requirements are. 

Frequently Asked Questions

faq how many footings do i need for a deck

  • Can I use concrete deck blocks instead of footings?

It is possible that you can use concrete deck blocks instead of footings. 

However, if you live in an area with a lot of frost, footings are recommended. They will be protected from the moisture and will not deteriorate so quickly. 

  • Can I build a deck without digging holes?

As with anything, the better you prepare for a deck, the longer it will last. 

Making sure that your deck has a quality foundation is essential. If you don’t bury your footings, it may start to sink within just a few months. 

  • What is the minimum height for a deck?

Most zoning laws require that your deck guardrails need to be at least 30 inches high. However, this changes from city to city. 

Your best bet will always be to contact a local code inspector and find out. 


Making sure that your deck has a solid foundation is the best way to make it last longer

Most decks need to be replaced after 10 years. If you follow the above considerations, you can keep the same footings and make less work for yourself. 

On top of that, you can be certain that your deck will be safe and secure for you and your family. 

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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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