Post Base - Wood Post to Concrete Support Guide Tips

A post base is a metal bracket that supports and secures the bottom of a wood post to concrete while helping keep the wood off the slab.

Post Base diagram — labeled parts, dimensions, and installation context

What It Is

A post base forms the bearing and fastening point between a post and the concrete or masonry below it. It is commonly used on decks, patio covers, and porch posts where the connection must resist uplift and side movement while carrying vertical load.

It is not just trim hardware. A true structural post base is rated for a specific post size, fastener pattern, and anchor type, and it must be installed as part of the engineered load path.

Types

Common types include standoff post bases, wet-set post bases cast into fresh concrete, retrofit bases anchored after the pour, and decorative light-duty bases for railings or landscape structures. Some are concealed, while others wrap visibly around the post.

Where It Is Used

Post bases are used at the bottoms of deck posts, porch columns, pergola posts, fence posts on piers, and other wood posts that bear on concrete. They are especially common where moisture exposure would make embedded wood a bad choice.

How to Identify One

Look at the bottom of the post for a galvanized or stainless steel saddle, bracket, or knife plate attached to the concrete with an anchor bolt or screws. The bracket usually matches the post width and may hold the wood slightly above the slab.

Replacement

Replace a post base when it is corroded, bent, pulling loose, or incorrectly sized for the post. Structural replacement work often requires lifting or temporarily bracing the supported framing before the old base is removed.

Post Base — FAQ

Is a post base required on a deck post?

In most modern deck construction, yes, a listed or engineered post base is used to connect the post to the footing or slab. Local code and the deck design determine the exact hardware.

What does a standoff post base do?

It raises the wood slightly above the concrete so water does not stay trapped at the post bottom. That improves durability and usually makes inspection easier.

Can I replace a rusted post base without replacing the post?

Sometimes, but the post has to be checked for rot and the structure may need temporary support during the swap. If the post bottom is damaged, replacing only the hardware is not enough.

Do I need a permit to replace a post base?

If the post base is part of a structural deck, porch, or other load-bearing assembly, permit requirements are common. Cosmetic landscape structures are less likely to trigger one, but structural work often does.