2011 October Lumber Talk.com: Professional-Level information and how-to-build articles for wood, timber, and lumber professionals and users. 2011 October » Lumber Talk
By Chris | October 4, 2011 - 11:45 pm - Posted in Alternative Materials, Decks & Fences, Farm & Ranch, How To, Poles, Posts, Pilings

What is the best fence post depth? That depends (of course) on what type of fence you are building and which post you are putting in the ground. We’ll cover a few here with some general fence builder rules.

Privacy Fence Post Depth — 1/3 of Height

The general rule of thumb for privacy fence posts is to bury them 1/3 the depth of the height of the post. This is easy for your typical privacy fence. Use 8? posts, bury 2? in the ground, and you’re left with a 6? post on which to build a fence.

Concrete is still a good idea (I recommend it), especially if you live in an area with high winds or occasional hurricanes. I’ve even drilled a 9/16? x 8? hole in the bottoms of the posts and driven a piece of re-bar in with about 12? sticking out. The result is a post buried 2 feet in the ground, with re-bar another 12? (driven into the clay soil), surrounded by concrete — very strong posts. Overkill? Whatever, dude.

Farm & Ranch Fence

Your typical farm or ranch fence, especially one with wire stretched, has 2 types of posts — line posts and corner posts.

Use the 1/3 of height rule for the line posts depths. With 6 foot posts, you will probably bury 1.5 to 2 feet and end up with a 4 to 4.5 foot post. For corner posts, you might want to use a rule of 1/2 the height for the fence post depth. So, a 5 foot tall corner post would probably be buried 2.5 feet in the ground — probably more like 3 feet buried of an 8? post.