Deck Footings & Frost Depth in Central Ohio

It's the part of a deck nobody sees and everybody's deck depends on: the footings. In Central Ohio, getting them right isn't optional — our freeze-thaw winters punish any deck built on footings that stop too shallow. Here's what actually goes on underground, why depth matters so much here, and how the options compare.

The short answer: below the frost line

Deck footings in Central Ohio have to reach below the frost line — the depth to which the ground reliably freezes in winter. Local codes here generally put that around 30 to 32 inches, though the exact minimum is set by your building department (the Delaware County office and each village or township can specify it) and is confirmed when you pull the permit. A footing poured to that depth sits in soil that stays unfrozen all winter, so it doesn't move.

A note on wording, because it trips people up when they're searching: you'll hear footings called footers, and the frost line called the freeze line. Those are the same things — footing and frost line are the terms on the plans and in the code book, while footer depth and freeze line are what most people actually say out loud. Whichever words your contractor uses, the number is what matters: below the local frost depth, confirmed at permit time.

Why frost depth is the whole game

When wet soil freezes it expands and lifts — that's frost heave. Central Ohio doesn't freeze once and stay frozen; it crosses the freezing point dozens of times each winter. A footing that ends above the frost line gets shoved up and dropped back down over and over. Multiply that across a season and the result is a deck that's out of level, a ledger board straining against the house, railings that rack, and gaps that open at the connections. A footing anchored below the frost line simply doesn't ride that cycle. This is the same reason a paver patio outlasts a concrete slab here — freeze-thaw is the deciding force for anything built on Ohio ground.

Your three footing options

• Poured concrete piers — the standard for permanent decks here. A hole is augered below the frost line and filled with concrete, often with a wider base and a post anchor set on top. Proven, strong, and what most inspectors expect to see.
• Helical (screw) piles — steel piles driven down to load-bearing depth. Great for tricky soil, tight access, or when you want no concrete cure time; typically costs more than poured piers.
• Precast deck blocks — surface blocks that sit above the frost line. They heave in Ohio winters, so they're only appropriate for a temporary or floating ground-level platform — not a permanent attached deck, and generally not approvable for one.

How deep does the deck post itself go?

Worth separating two questions that often get merged. The footing is the concrete below ground; the post is the wood or steel column standing on it. On nearly every permitted deck we build in Central Ohio, the post doesn't go into the ground at all — it lands on top of the pier on a galvanized post base that holds it a fraction of an inch above the concrete, so water drains away instead of wicking up into the end grain and rotting it from the bottom.

So when someone asks about deck post depth, the honest answer for a modern deck is usually zero — the post sits at grade and the footing beneath it carries the 30-to-32-inch requirement. Buried-post designs (a treated post set directly in a concrete-backfilled hole) do still get built, and they can be structurally fine when the post is rated for ground contact and the hole reaches below frost depth. We don't default to them: a post in the ground is the part you can't inspect later, and replacing one means disturbing the footing it's cast into. Either way, the depth that matters is measured to the bottom of the concrete, not to the bottom of the wood.

Depth isn't the only spec

How wide a footing needs to be depends on what it carries — the deck's size, height, and the soil's bearing capacity. A tall or large deck concentrates more load on each post, so footings get bigger. This is exactly the kind of thing the permit and inspection process checks, which is one more reason a deck should be permitted properly rather than built on guesswork.

The inspection step

On a permitted deck, the building department inspects the footings before any framing goes up — confirming depth and diameter while the holes are still open. We dig to code depth, call for that inspection, and don't build over it until it passes. It adds a day to the schedule and it's worth every hour: it's the one part of the deck you can never check again once it's covered.

That's the same footing spec on every deck we build — whether it's a new deck in Lewis Center, a composite deck replacement in Powell, or a walkout deck in Galena. The frost line doesn't care which township you're in.

What about patios and porches — do those need frost footings too?

It depends on whether the structure is rigid and whether anything is holding a roof up. A paver patio sits on a compacted aggregate base rather than footings, so it is designed to move with the ground instead of resisting it — that flexibility is the whole reason a properly based paver patio survives freeze-thaw where a slab cracks. A screened porch is the opposite case: it carries a roof, so its posts take the same below-frost footings and the same footing inspection as a deck, sized for the added load. Anything roofed gets treated as structure, not as decking. If you are still deciding what to put behind the house, our Sunbury deck and patio builder pages walk through both.