Fence Post Depth Code

You need to dig a 12 inch wide hole for a 4 foot wood post.

Fence post depth code.

Gates require a hole with a depth of 36 to 40 inches in the ground and with a diameter of at least 12 inches. As a general rule of thumb you ll need to place at least 1 3 the height of the post in the ground. The maximum frost line depth is 100 inches as seen near the tip of minnesota north dakota and alaska all the way to zero inches in florida southern arizona and southern california. It s a lot harder to push over a post that s buried deeply so always keep that in mind.

If not conventional rules of thumb offer a reliable guide. For example a 6 foot tall wood fence may need 4 x 4 or larger posts spaced no more than 6 feet apart and buried in the ground at least 2 feet deep. Common construction requirements include post size spacing and depth. Check your frost line by zip code or address using this map from the national weather service.

If your post is 6 feet tall you will dig down at least 2 feet. For a fence a little heaving is not easy to notice and does not destroy the servicability of the fence. The depth of your post hole plays a key role in the strength of your posts. For example if you are building a fence that s 6 feet tall you will need a hole that is at least 2 feet deep.

That also means that you d need to use an 8 foot post. Frost line by zip code. If the map isn t accurate enough for you. For example a 6 foot tall fence will need at least 2 feet of post in the ground.

Others leave that up to the builder. For the width you need to make the hole three times the width of the post you intend to use. The depth of the post hole needs to be 1 3 to 1 2 the height of your fence. The code frost depth is meaningless for a fence.

Building codes and ordinances in your area may stipulate a legal depth and diameter for fence post holes. If you re setting a post into soft ground or in an area that receives high winds it s always a good idea to bury your posts a little deeper and add more concrete. Keep the height of your fence in mind when digging your post holes. Some cities say posts must be set in concrete.