How Many Footings Do I Need for a Deck?

How Many Footings Do I Need for a Deck

How many footings do I need for a deck: It depends on the deck size, floor, and beam. The larger the shaft and base size, the fewer the number of legs. In most situations, you’ll want to keep the legs and poles at least 8′ apart.

If you plan to install a hot tub or veranda on your deck, you’ll usually need more legs and posts for extra edging. A freestanding deck attached to the house with ledger boards does not require beams and another row of floors. Decks with lots of corners may also require additional legs.

Also Read: White Oak Vs Red Oak Flooring

What Is a Deck Footing?

What Is a Deck Footing

Deck footings are an essential part of a deck’s support. Basement posts hold the weight better, prevent them from sinking into the ground and keep the decking level. To maintain weight, deck foundaitons within the environment often must be below frost level.

Use non-crumbling materials such as concrete and gravel to stabilize and strengthen your deck’s foundation. Deck posts “quite literally” stand on solid ground, distributing and holding the weight of the entire decking structure.

A good rule of thumb using concrete foundation piles is one shed every 8-10 feet. This means an 8×10 shed should have four steps when support is needed, while a 16×40 shed should have about 15. Solid concrete footing holes need to be installed below the frost line.

A good rule of thumb is that you should only have footings at most eight feet. You will usually require more if you plan to install a hot tub or veranda on your deck.

A standard rule of thumb for footings is that the larger the size of the beams and feet, the fewer footings you will need for the original deck. On average, if you’re building a simple deck, the floor, and posts should be 8 feet apart.

However, if your deck includes a hot tub or terrace, you should support that weight more closely with other legs. Or, if your deck has multiple corners, separate foundations are required.

The web in the bases shall not exceed eight feet. Net, the standard rule for flooring is that the larger the beams and bottoms, the fewer feet you will need for a basic deck. You can usually get away with a 15×15 base and then at least six thick so you don’t break the deck.

You can use engineered beams to reduce the number of stories, but the construction cost will likely increase. Before you begin building the deck, it is recommended that you make sure footing spacing meets local building codes.

5 Types of Deck Footings

1. Concrete Foundations Were Laid at the Site:

Concrete Foundations Were Laid at the Site

One of the most familiar footing types is the site-poured concrete footing. Concrete is mixed and sprayed directly on your job site. An important one of these types of foundation is customized in any shape or size as per your requirement. This provides more flexibility for your deck design.


  • Poured concrete footings are the most common type of deck footing.
  • They provide super stability and cushioning.
  • They are considered a good choice for decks in areas with cold winters.


  • Installing them is expensive.
  • Installing them requires much labor and time.
  • If any damage occurs, it is challenging to repair.

2. Buried Post Footings:

Buried Post Footings

Buried post footings are often used on low-profile decks or near the ground. Concrete is poured around buried posts that extend above ground level with this foundation. Seats are usually made of wood but can also be made of steel or composite materials.


  • It is a good choice for deck posts that are large or tall.
  • The sound of post footing depends on the frost line in your area.
  • The deck vehicle is attached to the posts with bolts and lag screws.


  • They are less common than other types.
  • They are expensive to install.
  • If any damage occurs, it is challenging to repair it.

Also Read: What Is Lintel? | Size of Lintel Beam | Types of Lintel

3. Screw/helical Piles:

helical Piles

A new type of footing, screw, or helical pile is driven into the ground until it reaches the solidified soil layer. These piers are then used to support the deck structure. This type of footing is often used on slopes or adjacent to fragile systems where conventional foundations are difficult to install.


  • They are a good choice for soft soil or unstable ground decks.
  • It is sustainable.
  • It is lowered into the ground with a hydraulic screw drive.


  • It is more expensive than other types of deck footing.
  • Installing them takes a lot of labor and time.
  • Challenging repair of any damage.

4. Deck Blocks:

Deck Blocks

An easy and most economical step, deck blocks are also small precast concrete pillars that support the weight of your deck in the basement. Deck blocks are thus placed at regular intervals around the perimeter of your deck. And they are easy to install but less intense than other fittings.


  • Applying them is easy.
  • They don’t need any digging.
  • It is less expensive than other types of deck footings.


  • It is unstable. If you live in an area with uneven ground, there are better options than deck blocks for you.
  • It is less common than other types of deck footings.

5. Precast Concrete Deck Post Footings:

Precast Concrete Deck Post Footings

One of the most familiar footing types, precast concrete piers are poured, fixed off-site, and transported to your deck construction site. They are usually round or square, and the concrete passes through steel reinforcing bars and rebars. This design provides both concrete strength and steel reinforcement to precast concrete piers.


  • It installs quickly.
  • No need to dig it.
  • It comes in various shapes and sizes.


  • Precast units require specialized labor to lift, move and set up.
  • They can be expensive to install.
  • If any damage is done, it takes work to fix it.

The number of feet you need depends on the design and size of the deck and the size of your beams. Wider spokes and foot sizes require fewer feet. You can use a footing and beam calculator to determine how many footings would be best for your deck design. To get an accurate calculation, you will need to know the following:

  • Ridge span
  • Joist span
  • Deck footing size

A 12-foot by 12-foot attached deck foundation requires three 12-inch diameter deck footings. If you are building a stairwell, it will need at least two more. You’ll want to space and post at least eight feet in the center. If you install heavy items like a hot tub or porch on your new deck, you’ll need more legs and posts to support the extra weight.

Also Read: What Is the Difference Between Ho3 and Ho5 Homeowners Policies?

Deck Post Spacing And Beam Size

The size of the deck Beam size Footing spacing Number of footings
8’ x 10’ (2) 2×8 6’0” 2
10’ x 10’ (2) 2×8 8’0”* 2
10’ x 12’ (3) 2×8 8’0”* 2
12’ x 12’ (2) 2×6 6’0” 3
16’ x 16’ (3) 2×8 7’0”* 3
20’ x 12’ (2) 2×8 6’0”* 3
20’ x 14’ (2) 2×8 6’0”* 3
20’ x 20’ Two beams (2) 2×8 6’0”* 6 (2 rows of 3)

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Frequently Asked Questions

How Many Footings Do I Need for a Deck?

he answer depends on the size and shape of your deck, the size of your footings, and the size of your beams. The larger the beam and footing size, the fewer footings that are required. For most situations, you will want to place footings and posts less than 8′ apart.

How Many Deck Footings Do I Need?

Before starting to build, the first question is: How many footings do I need for a deck? For an attached 12 x 12′ deck, you’ll need at least 3 footings, plus at least 2 more if you’re planning on building stairs with it. If your deck will be a different size, it’s easy to figure out how many you’ll need.

Do You Need Footings for a Deck?

In general, a deck footing is usually used if it is going to be higher than your waist or larger than 100 square feet. The footings ensure that the deck will not fall, tip or rot away after a few years.

What Is the Best Footing for a Deck?

Poured Concrete Footing
A poured concrete footing is going to be your strongest, most permanent and stable deck footing. While similar to a buried post footing in that it involves pouring concrete to below the frost line, a poured concrete footing includes additional fortification by metal brackets.

How Deep and Wide Do Footings Need to Be?

The depth of concrete you need will depend on the use: footings for extensions, for example, will need to be at least 200mm thick, while around 100mm should be deep enough for a shed base.

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