Repairing a Concrete Deck Footing for Decking Posts

How to Restore your Deck to a Level Footing

By Mark J. Donovan

When a deck is built with improperly installed concrete deck footings, the deck can heave or sink as the decking posts rise and fall with the moving deck footings. When this situation arises repairing concrete deck footings is a must.

In colder climates, if the concrete deck footings are installed above the frost line, the deck footings or deck concrete pads often heave up during the cold weather and then sink down when the warm weather returns. Repeated cycles of this type of action often lead to a deck surface that is no longer level.

How to Repair Deck Footings

To repair a concrete deck footing you first need to brace or jack up the deck near the area of the particular deck footing. 

Consider using deck piers when building your deck as an alternative to using concrete deck footings.

If the decking post is mechanically fastened to the deck footing with deck post anchor bolts remove them so that the deck post can easily rise up when you jack up the deck area.

Next, use a shovel to dig out around the deck footing. Be prepared for some hard work. Wear work gloves and proper shoe wear and plan some serious digging.

Once you have fully exposed the deck footing or concrete deck footing pad, break it up with a sledge hammer and remove all the pieces. Make sure to wear eye protection when breaking up the old deck footing or concrete pad.

After removing the old concrete deck footing, continue to dig down deeper in the footing hole until you are at least 6 inches below the frost line area for your local area. Make sure the base of the hole is wider than the top of it when digging out the hole.

 Repairing a Concrete Deck Footing

It is important to understand that deck footings support a serious amount of weight. A small deck, for example, with deck furniture and people on it can easily way in at over 10,000 lbs.

Consequently it is important to install new deck footings that are 12-24 inches in diameter to provide an effectively wide enough area for supporting a significant portion of the weight of the deck.

In addition, it is important to have the deck footing wider at the base of the hole. By creating an upside down funnel shaped hole, if you will, it becomes more difficult for frost to push a concrete deck footing pad upwards.

After digging out your deck footing hole, visit your local home improvement store to find Sono-tubes with wide plastic footing form bases.

Place the Sono-tube with the attached footing form base into your deck footing hole and use a level to plumb it. Also use a plumb bob to position the Sono-tube directly under the existing deck post.

After ensuring that the Sono-tube is plumb backfill dirt around it. Then pour concrete into the Sono-tube to create the new deck footing. 

Deck Installation Bid Sheet

Use this deck installation checklist and save time and money on your deck construction project.

As you pour the concrete into the Sono-tube, place a few vertical reinforcing steel bars (re-bar) into the Sono-tube to increase the strength of the deck footing. After pouring the cement, install mechanical deck footing anchor hardware into the top surface of the concrete.

Allow the new deck footing to setup for 24 to 48 hours, depending upon weather conditions, and then re-attach the deck post to the repaired deck footing. You may need to trim the decking post, depending upon the new height of the repaired deck footing.

Finally remove the bracing and your deck should once again be level.  You should have no more issues with heaving concrete deck footings, decking posts and your deck.

For help on building a deck, see’s Deck Installation Bid Sheet. The Deck Installation Bid Sheet will teach your how to hire the right deck contractor, and help to ensure that your deck project is completed on time and budget.

Deck Installation Bid Sheet

Related Information on Installing Concrete Deck Footings and Decking Posts

Additional Deck Building and Design Resources

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