Types of Footings

• The type of footing that is suitable for your deck depends on the height and size of the structure along with the soil it will be constructed upon. In climates where frost is not a issue, precast concrete piers work well and require less work to install than in frost prone climates. In colder climates, you must dig beneath the frost line to install the footings, which often requires a poured foot because of the depth. There are several tube-like systems on the marked which make it easier and more efficient to install this footing type, but you can generally simply dig holes to the correct depth and add concrete if your soil is firm enough to maintain the opening until you're done.
  
  

Size of Footings

• If using concrete pier block footings to construct a low, freestanding deck, you should dig a hole at least 3 inches wider than its base or as wide as your local building codes require. When using circular footings determine the square footage of your intended deck, the total weight the footings will be supporting and the type of soil. Once you have these calculations you can contact your local building inspections department to obtain the proper size requirements to construct your footings.
  
  

Depth for Footings

• In mild climates where frost lines are not an issue, you can usually pour a 12 inch deep shallow footing, and embed a precast pier block 1 inch into the concrete while it's still wet, but firm enough to handle the weight. The tops of your the piers should be at least 3 inches above ground. If the soil is stable and firm you can sometimes place the piers directly on the ground, where local building codes allow.
  
  

Footing Inspection

• Though some smaller, low-level decks and their footings can be built without a building inspection, most footings must be approved before you can construct the deck. A building inspector will measure your foundation holes to verify that the size and depth meets local building codes along with the approved building plans. The inspector will also require that the holes are clear and dry in preparation for the concrete pour. Once the holes have passed inspection, you can pour the concrete to continue the completion of your footings.