Better Deck Piers

When a pier is angled, deck loads are transferred to the pier’s side rather than its bottom, which can cause it to sink. Also note the voids—a result of too many large rocks in the concrete mix—that have weakened this pier.

A penetrometer has a spring-loaded piston that retracts into the tool when it’s pushed down; when released, the tool relaxes to full extension leaving a friction indicator ring at the maximum level of compression. Here, the scale reads 2.25 tons, indicating a soil bearing capacity of 2.25 tons—or 4,500 pounds—per square foot. Because it’s difficult to take measurements at the bottom of footings deeper than arm’s length, the author tapes the penetrometer body to a stick and uses a mirror mounted to another stick to view the penetration scribe mark.

Footings that are sized based on actual deck loads and soil conditions are usually smaller in diameter than when they’re sized using prescriptive methods. This makes digging holes for them much easier, especially when frost depths are more than 3 feet below grade.

Join the Discussion

Please read our Content Guidelines before posting

Close X