How to Set Deck Posts in Concrete Footings

Concrete serves as the literal foundation for a deck's structural integrity. A common misconception is that posts should be buried directly in wet concrete; doing so traps moisture against the wood, leading to inevitable rot and structural failure. Instead, you want to pour a solid, code-compliant pier and anchor the post atop it using specialized metal hardware. Getting this right requires a level head and careful measurement before you ever touch a bag of mix. A deck built on shaky footings will shift, crack, and settle over time, ruining your decking surface and creating safety hazards. By focusing on deep, frost-line-depth holes and using proper post bases, you ensure a rigid base that lasts for decades.

1. Dig Below the Frost Line. Mark the post locations with stakes and strings, ensuring everything is square. Dig holes that extend below the local frost line and are at least 12 inches in diameter.
2. Level Every Tube Twice. Place cardboard concrete form tubes into the holes. Level the tops of the tubes and backfill around them with dirt to hold them firmly in place.
3. Mix and Pour Strong. Mix your high-strength concrete in a wheelbarrow or mixer until it reaches a thick, consistent oatmeal texture. Fill the tubes, tapping the sides to release trapped air bubbles.
4. Align Anchors Perfectly. While the concrete is still wet, press your galvanized post-base anchors into the center of the pier. Use a string line to ensure all anchors are perfectly aligned in a straight row.
5. Wait Two Full Days. Check the alignment once more before the concrete sets. Allow the footings to cure for at least 48 hours before applying any weight to the anchors.
6. Bolt Posts Plumb. Once cured, bolt your pressure-treated posts to the anchors using structural hot-dipped galvanized lag screws. Verify that each post is perfectly plumb in two directions.