Concrete
deck footings provide the base for the whole deck or porch structure.
Deck footings should be at least twice the width of the posts that rest on them (in our case 12" wide footings).
During the process of getting a permit
for your new deck, you should find out the required depth for the
deck footings. Wherever the ground freezes, deck footings need to be dug below the frost line to prevent frost upheaval.
The depth may vary from 12" in southern climates, to 48" (or more) in northern climates.
Dig the
deck footing holes using post hole diggers if footings are fairly deep. The diggers keep the holes uniform -- keeping concrete use to a minimum. Our footing holes were 42" deep and took some time to dig. If this sounds like your situation, you may want to rent a power auger.
TIP:
Dig the hole wider near the bottom. This "lip" will help anchor
the concrete in the ground.
Double-check the hole depths and widths before hand-mixing or ordering ready-mix concrete. If you're hand-mixing, make sure you know how much will be needed. One 12x42 hole took us 10 bags to fill, so we ordered cement!
To prevent air pockets and to promote settling, fill each footing hole with about 1' of concrete, tamp it in with a shovel handle, then repeat until the hole is filled.
Fill each hole with concrete until it's level with the ground. Set a small 2x4 on edge, set a level on the 2x4 and screed the footing smooth. Then finish it with a hand float.
Let the footings set up and cure for a few days.
After that, we put down black plastic to prevent weed growth under the deck. We poured and leveled landscaping rock on top of the plastic to hold it down and to prevent tearing it while we worked on the framing.
