There are two ways to put a fence post in the ground. You can drive it, with a hydraulic post driver or a hand driver for T-posts, so the soil is compacted around it as it goes in. Or you can dig a hole, set the post and fill around it with concrete or tamped dirt. We do both every week, and the choice is not about preference. It is about the soil, the fence and the job the post has to do.
Driven posts
Driving pushes a post into undisturbed soil, which packs tight around it. Done in firm ground, a driven wood post is held along its whole length and does not loosen the way a post in a backfilled hole can. It is fast, there is no hole to dig and no concrete to cure, and the post can be worked on the same day. Steel T-posts are always driven; that is what the anchor plate is for.
Where driving falls down is soft ground. In lakeshore sand or wet bottomland the soil does not pack, and a driven post leans the first time something pushes on it. Rock and heavy roots stop a driver cold. And a driven post cannot be plumbed or adjusted much once it is in.
Set posts
Setting means digging the hole, usually with a tractor auger, placing the post, plumbing it and filling the hole with concrete. The concrete makes a footing larger than the post, which is what holds in sand and soft soil, and the post can be plumbed exactly before the concrete sets. It is the method for every post that carries a load: corners, ends, braces and gate posts on every fence, and all the posts on wood privacy fence, ornamental fence and anything else where the posts are the structure.
The things to get right: dig below the soft top layer, do not let the post sit in a wet hole on bare dirt (a few inches of gravel under a wood post), crown the concrete so water sheds away from the wood instead of pooling against it, and let it cure before loading it.
How we decide
| Situation | What we do |
|---|---|
| T-post line on pasture | Drive |
| Wood line posts on firm upland soil, wire fence | Drive or set, depending on the ground; often drive |
| Corners, ends, braces, gate posts | Set in concrete, always |
| Wood privacy, picket, horizontal fence | Set in concrete |
| Chain link, ornamental, aluminum | Set in concrete |
| Sand or soft soil near the lake | Set, deeper, bigger footing |
| Rock or heavy roots | Set; a driver will not go |
Depth matters more than method
A post driven or set too shallow fails either way. The rule is below the soft layer and below where the soil moves between wet and dry, with corners and gate posts deeper still. On a lake lot that can mean considerably deeper than the same fence on a clay hill. The art and science of fence construction covers the rest of what holds a fence up.
Cost
Driving is cheaper per post, which is part of why T-post pasture fence is economical. Setting costs more in labor and concrete and buys a post that holds in any ground and can be plumbed exactly. On a fence that is supposed to stand twenty years, the difference is small next to the cost of resetting a leaning run. See T-post fence and wood fence.
Frequently asked questions
Is a driven post stronger than a concrete-set post?
A driven wood post in good soil can be as strong as or stronger than a concreted one, because the soil is packed tight around it. In sand or soft lake soil, concrete wins. For corners, gates and braces we set in concrete either way.
Why do some concrete-set posts rot faster?
Water pools in the top of the concrete collar around the post and sits against the wood. We crown the concrete so water sheds away, and keep wood posts off the bottom of the hole on gravel where the ground stays wet.
Do you drive T-posts or set them?
T-posts are always driven; that is what they are for. The wood or pipe posts at corners, ends and gates are set in concrete.