Deck Footings

Deck footings, part 3 (of 7) of the 10 x 10 how to build a deck tutorial, provide support at the base of your vertical posts.

Build your own deck

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Design Framing Footings Decking Stairs  Railing Stair Railing

The size and depth of footings vary depending on your location and soil composition. For example, in Northern Virginia, a deck's footing needs to be at a depth of 24" below the ground.  In more southern locations, many concrete footing details indicate that the footing can be placed much closer to the surface.

You must check the building code for your area to determine the size and depth of your footings.

Building Deck Footings

In Austin, Texas (in 1987) footings could be placed on top of the ground. Generally, they should be placed upon "undisturbed" earth, meaning that if topsoil was brought in to level the ground, etc., you should dig down to where the bottom of the footing is resting on solid ground. 

The top of the footing can be above the ground.  You can build a simple concrete form out of 2x material to support the freshly poured concrete until it sets up.

Deck Footing
Corner post and footing detail

Once you have built the form, notch the 4" x 4" vertical post as shown in the diagram above and cut the post to where it will be about 1" below the top of your form.  This is so that once you fill up the form with concrete, it will surround the bottom part of the post.

Plumb the post.  Mix some ready-mix concrete in a wheel barrow (or other large container), and pour or shovel it into the form until it surrounds the base of the post. When the concrete hardens, it will not only vertically support the post, but it will keep it from sliding from side to side.

  1. Anchor bolts
  2. Ledger board
  3. Joists (typical)
  4. Band board
  5. Vertical post
  6. Concrete footing (shown with form)
Deck Frame
Completed deck frame with footings poured

Let the concrete harden for about 24 hours.  Remove the wood forms and the temporary supports used to hold up the end of the deck.  The deck frame and footings are now complete.

For deck design and structural information, check out the Prescriptive Residential Wood Deck Construction Guide, by the American Wood Council.

What next?

Continue to step 4 (of 7) - (Decking)

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