Porch Posts and Columns: Repair or Replace the Rotted Base

Wood porch posts rot from the bottom up in Florida. How to tell how far it has gone, how a post is jacked and replaced, and materials that will not rot again.

The bottom six inches of a wood porch post do most of the failing. Rain splashes up from the deck or slab, the end grain drinks it in, the paint film breaks, and rot works upward inside a post that still looks fine from the street. By the time the paint bubbles or a screwdriver sinks in, the bottom of the post is often gone and the porch roof is resting on the paint shell. This is one of the most common exterior carpentry repairs we do in Polk County, and it is very fixable.

How to check a post

Push a screwdriver or an awl into the post an inch above the base on each side. Sound wood resists; rotted wood gives with almost no pressure. Do the same at the top where the post meets the beam, because water also gets in at that joint. Tap along the post and listen for the hollow sound of a rotted core. Look at the base plate or the trim collar: rot usually starts behind it, where water sits. If the post is hollow or soft more than a few inches up, it needs replacing. If the rot is limited to the bottom couple of inches, a splice repair is possible.

What is holding the roof up meanwhile

A porch roof is heavier than it looks, and a rotted post has usually been transferring load to the paint, the trim and the nails for some time. Before a post comes out, the beam is supported with a temporary post and a jack, set on a solid footing, and lifted just enough to take the load. Skipping this is how a roof sags, a beam cracks or a person gets hurt. It also means one post at a time; the whole porch is never left on temporary supports.

Repair options

• Splice the base. The rotted bottom section is cut off square, and a new section of matching post is joined to it with a concealed splice and structural adhesive. Practical on large square or turned posts where matching a whole new post is difficult, and only when the rot is confined to the base.
• Replace the post. The cleanest fix. A new post is cut to length, set on a proper standoff base, and fastened to the beam above. Turned and decorative posts are matched from stock profiles or, for a historic porch, milled to match.
• Replace the wrap, keep the structure. Many newer Polk County porches have a small structural post inside a decorative wrap. If the wrap is rotted but the post is sound, only the wrap is replaced.

Stop it from happening again

The reason posts rot is that their end grain sits in water. Every replacement we do addresses that:

• A metal standoff base lifts the post off the slab or deck so water cannot pool against the end grain.
• The bottom end of the post is sealed with a primer and paint before it is set, not after.
• Any trim collar at the base is fitted so it sheds water rather than trapping it.
• The top joint at the beam is flashed or caulked, and the paint is maintained.

Our post on why wood rot is so common here explains the moisture side, and the soffit and fascia guide covers the trim above the posts that fails next.

Materials that do not rot

For a post that will not need this repair again, fiberglass and PVC columns look like painted wood and are immune to rot, termites and moisture. Structural fiberglass columns can carry a roof; PVC wraps go over a treated or steel post. Aluminum is another option for a simpler porch. On a historic home in Lakeland's older neighborhoods or in Bartow, a wood post may be the right choice to match the original details, and it can last decades if it is installed with a standoff base and kept painted.

The rest of the porch

While a post is out we look at the beam it carries, the railing attached to it, the deck or slab it stands on and the ceiling above. Rot rarely stops at one piece. Fixing the post and leaving a soft beam end is the kind of half repair we do not do. If the porch railing is also failing, our post on railings and handrails covers the options.

Cost in the Lakeland area

A single post replacement with a standoff base is a modest carpentry job. Turned or decorative posts, structural beam repair, or replacing all the posts on a wraparound porch scale the price up. We give an exact figure with a free estimate after checking every post, not just the one that looks bad.

Inventive Home Improvement handles porch posts and columns as part of our carpentry services and exterior repairs in Lakeland, Bartow, Fort Meade and across Polk County. Call (863) 633-5499.

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