Fence Post Installation Guide

Setting wood, vinyl, and metal posts in concrete — depth, spacing, and curing.

Properly set posts are the most important part of a long-lasting fence.

Hole Dimensions

Dig holes 3× the post width in diameter, and 1/3 the above-ground height plus 6 inches of gravel. In freeze zones, go below the frost line.

Setting in Concrete

Add 6" of gravel for drainage
Place post and brace plumb
Pour dry-mix concrete and add water (or pre-mix)
Slope concrete crown away from post
Cure 24–48 hours before adding rails

See our Concrete Calculator to estimate bags needed and step-by-step blog guide.

Choosing posts? See our fence post buying guide.

❓ Frequently asked questions

How deep should a fence post go?

One third of the above-ground height is the working rule, so a 6 ft fence wants a post about 2 ft in the ground, plus 6 inches of gravel beneath it. In freezing climates the hole has to reach below the local frost line regardless of what the one-third rule gives you, or the post will lift every winter.

How wide should the post hole be?

About three times the post width. A 4x4 post wants a 10 to 12 inch hole. Narrower than that and there is not enough concrete around the post to resist it being levered sideways by wind on the fence, which is the load that actually matters.

Do I need gravel at the bottom of a fence post hole?

Yes, about six inches of it, tamped. Concrete poured straight onto soil creates a cup that holds water against the bottom of the post, which is exactly where posts rot first. Gravel lets that water drain away instead.

How long does concrete take to set before I can hang rails?

Fast-setting mix holds a braced post within 30 to 40 minutes and takes load after about four hours, but give it 24 hours before hanging rails and pickets if you can. Standard bagged concrete wants a full 24 to 48 hours. Leave the bracing on for the whole cure either way.

Should the concrete be crowned above ground level?

Yes. Slope the top of the concrete away from the post so rain runs off rather than pooling at the joint. A flat or dished concrete top is a puddle that sits against the post after every shower.

Fence Post Installation Guide

Hole Dimensions

Setting in Concrete

❓ Frequently asked questions

How deep should a fence post go?

How wide should the post hole be?

Do I need gravel at the bottom of a fence post hole?

How long does concrete take to set before I can hang rails?

Should the concrete be crowned above ground level?

📬 Free Fencing Cost Guide

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