Common deck footings include concrete poured directly into excavated holes, concrete poured into cardboard tube forms or cast concrete blocks, called piers, that rest directly upon the ground's surface. Checking local building codes is the most important aspect of building deck footings. Areas that regularly receive freezing temperatures require larger and deeper holes than areas with little or no frost. Local building authorities or licensed contractors can help you determine the right type of footing for your deck construction project.
Dig the deck post's footing with a shovel or a posthole auger. Refer to local building requirements for hole diameter and depth requirements. In general, add approximately 6 inches to the hole's depth for a layer of compacted gravel.
Fill the bottom of the hole with approximately 6 inches of gravel and compact the gravel with a tamper. Combine concrete mix and water in a wheelbarrow or concrete mixer according to the concrete manufacturer's instructions.
Pour concrete mix into to the hole until concrete reaches the ground's surface. Smooth the poured concrete with a concrete trowel and insert an anchor bolt or post bracket if required by the deck design. Use a level to adjust the anchor bolt or post bracket on both horizontal and vertical planes.
Dig the tube form's hole with a shovel or posthole auger. Excavate the hole according to local building requirements and leave adequate space for gravel beneath the tube form and around the form's sides.
Fill the bottom of the hole with gravel according to design specifications or local codes, often approximately 6 inches. Compact the gravel with a tamper. Insert the tube form into the hole, place a level across the form's top and use the level to level the form's top surface.
Fill the sides of the tube form's hole with gravel and lightly tamp the gravel with a tamper. Mix concrete mix in a wheelbarrow or concrete mixer according to manufacturer instructions, fill the tube form with concrete and smooth the concrete with a trowel. If required by design, insert an anchor bolt or post bracket into the concrete and level the hardware with a level.
Smooth the ground's surface with a shovel or rake to create a pad for the concrete pier. Compact the pad by pounding the ground with a tamper.
Place the concrete pier atop the smoothed, compacted pad.
Place a level atop the pier and use the level to adjust the horizontal position of the pier's top surface. If necessary, remove the pier from the pad, add soil and compact the soil with a tamper to adjust the levelness of the pad.
Consult local building authorities to determine allowable footing types, hole depths and hole diameters.
Many municipalities require deck footings to protrude above the ground's surface; direct-pour post holes do not protrude above grade unless reinforced with wood frames. Pre-cast piers are usually prohibited in areas that regularly experience freezing temperatures.