Every deck sits on its footings. If they settle or heave, the whole deck goes out of level, boards pull apart and railings loosen. For decades the standard footing was a hole in the ground filled with concrete. On many of our decks we now use ground screws from American Ground Screw instead. Here’s what they are, why we like them for Utah, and when concrete is still the right call.
What a ground screw is
A ground screw is a heavy steel shaft with a helical thread, like a giant lag screw. We drive it into the soil with a hydraulic driver until it reaches the required depth and resistance. A bracket on top connects to the deck post or beam. Ground screws are galvanized to resist corrosion.
Why footings matter so much in Utah
Utah soils give footings a hard time:
- Frost. Water in the ground freezes and expands in winter. A footing that doesn’t go below the frost line can get pushed up, then drop back down in spring. Your city’s building department sets the minimum depth.
- Clay. A lot of Utah County has clay soil that swells when wet and shrinks when dry, which can move a shallow footing.
- Slopes. Hillside lots in places like Traverse Mountain, Eagle Mountain and the Pleasant Grove foothills often need tall posts and footings at very different elevations.
- Rock and fill. New subdivisions often have compacted fill, and older lots can hit cobble or rock.
Whichever footing you use, it has to be designed for the actual load and soil, and inspected.
How ground screws compare to concrete
Installation speed. Concrete footings mean digging, setting forms, pouring, and waiting for the concrete to cure before framing can go on. Ground screws go in and can carry framing the same day.
Less mess. Digging holes for concrete leaves piles of spoil in your yard, and the concrete truck or wheelbarrows have to reach the back of the house. Ground screws need a much smaller footprint, so there’s less damage to lawns and landscaping.
Weather. Concrete shouldn’t be poured into frozen ground or left to freeze while curing. Ground screws can be installed in cold weather, which helps keep a fall or early spring build on schedule.
Verified capacity. As each screw goes in, the installer can see the resistance it meets. That gives a real reading of how well that spot of soil holds, instead of assuming every hole is the same.
Adjustability. The connection at the top of a ground screw allows fine height adjustment, which helps set a level frame on uneven ground.
When concrete still makes sense
Ground screws aren’t the answer for every site. Very rocky ground can stop a screw before it reaches depth. Some engineered designs, very heavy loads, or specific city requirements may call for poured footings. On those jobs we pour concrete and do it right. We pick the footing based on the site, not habit.
Sizing ground screws
Footing type, size and depth depend on the deck and the soil, and we size ground screws to the manufacturer’s specifications.
Part of a frame built to last
Footings are the first step in building a deck that stays solid for decades. On top of them we often use Fortress Evolution steel framing, which won’t rot or warp, and we protect wood framing with G-Tape joist tape. Then the deck boards go on with hidden fasteners or Cortex plugs. You can read more in our built-to-last guide.
Ground screws on a deck rebuild
If your old deck’s footings have sunk or heaved, a full tear-out and rebuild on new ground screw footings is a clean way to start fresh without digging up the yard.
If you’re planning a new deck on a slope, in clay, or in a tight backyard, ask us about ground screw footings. See how we approach a custom deck build, or contact us for a free estimate over the phone.