How should post holes be dug to properly accommodate posts?

• A. Vertical sides
• B. 6 inches larger than the post
• C. Bottom 4 inches larger than the top
• D. Top 2 inches larger than bottom

Answer: (C)

When setting posts, the hole should taper so the bottom is wider than the top. This creates a stable footing for the post and gives space for the concrete to surround and grip the post on all sides. A wider bottom helps resist movement from loads, wind, and frost heave, and it helps water drain away from the post area rather than pooling at the top. In practice, making the bottom several inches larger than the top—for example, bottom 4 inches larger than the top—provides the needed stability and a solid concrete encasement around the post.