Somewhere in prepping for fall, football, and back-to-school shopping, it’s good to remember that your deck needs a check-up, too. It has served you all summer long, playing host to your BBQs and parties. Now, as you get ready for what’s sure to be several months of heavy snow and pooling ice around the base of your deck posts, it’s a great idea to check for and repair any damage your posts may have received from last winter.

Repeated seasons of heavy moisture, whether it be from rain, snow, or ice, can wreak havoc on any wood, even the pressure-treated variety. A thorough annual inspection will tell you if your posts suffer from mold, dry rot, or insect infestations that could significantly weaken their integrity.

Repair or Replace? What to Do When Moisture Attacks Your Deck Posts

(taradon / pixabay)

After all, the posts bear the brunt of your deck’s support, and if they fail, your deck fails. From 2003 to 2007, a study of Consumer Product Safety Commission statistics found that 224,000 people were injured nationally in porch and deck accidents. Almost 15 percent of those injuries stemmed from a structural failure or collapse. Not checking your deck regularly could easily cost you plenty, and I’m not just talking about money.

What happens when you find damage? Will you need to replace the whole post or just part of it? The answer depends on how extensive the damage has become. Since Colorado has such a dry climate, you’ll most likely find any moisture erosion in areas where water and snow accumulate and don’t drain off right away, usually at the bottom of your posts.

Look for darker areas, white spots, or fibers on the posts. That usually indicates mold or mildew. Then, take a screwdriver and gently poke the wood around the discolored areas. If the wood is soft and spongy or crumbles easily, you have dry rot. When you poke and the wood remains solid, however, you may still be able to effectively remove the mold and reseal the wood to prevent erosion. Another option is to have a professional custom deck builder take a look at it and make an assessment for you.

Insect damage, specifically termites, may be present if the exterior of the wood looks damaged and seems hollow inside. Piles of 1-2-inch termite wings or frass (termite droppings that look like sawdust) are pretty good indicators, as well. The best thing to do at this point is to call an exterminator to estimate the damage and provide insect mitigation. Once that is complete, you can go about replacing your posts.

How to Repair

If only a tiny part of your wood post is eroded and the rest is solid, a repair is in order. Repairing a deck post tends to be a little more time-consuming than a complete replacement, as you’ll need to attach a new piece of wood to the existing post.

First, you’ll want to measure the post to maybe a few inches past where you discovered the dry rot. You want to make sure you remove every bit of rotted wood. Using a Swanson tool, draw saw lines to measure the same height on all four sides of the wood.

Next, you’ll need to support the deck where you’re repairing the post. You can do this by using a hydraulic lift with two 2×6 boards nailed together. Lift to a height just under the joist where the top of the post meets the deck beam. If your deck starts to creak, you’re lifting too high, and you risk damaging the other posts and joists. Another way to support your deck while you’re working on the post is to stack large paving stones under your hydraulic lift, and then rest a couple of nailed-together 2×2 boards between the lift and the bottom of the beam. Whichever way you do it, make sure it’s secure.

At this point, you can do one of two things: Disconnect the whole deck post from the joist and remove it to another workspace; or saw off the damaged part, and drill a post base bracket to the bottom. This second method will require an above-ground concrete tube base, which turns out to be excellent protection for your deck post since the post base is up off the ground. It comes down to whether you like the look of short concrete pillars below your deck posts.

After drilling the bracket to the post, place your concrete form under the bracket. The sides of the form should be a few inches above the bottom of the post. Pour the concrete into the form until it reaches the bottom of the post bracket and let it cure for the amount of time designated in the concrete usage instructions. The post bracket is designed to leave a small space between the wood grain of the post and the bracket, so the post is not sitting in the concrete where moisture can accumulate.

You can drill the holes for the carriage bolts and secure the bolts to the bracket and post before the concrete is fully cured. Once cured, remove the form and you’re done.

If you decide against concrete, cut through the post at your saw line after removing the post to a different workspace. Next, you’ll need to clamp the new section of wood to the existing post with marine epoxy and let it sit overnight. Marine epoxy is better than wood glue because it’s designed to hold up in extreme aquatic environments. After the two pieces are securely attached and sanded to be flush with one another, then you can re-install the post to the existing base. It’s advisable to place a PVC or plastic shim between the bottom of the post and the base to create a layer between the ground and the wood grain. This will keep the post from sitting in the ground moisture.

How to Replace

Replacing your wood post is roughly similar to the methods used for repair, only you don’t have to worry about concrete pillars or gluing pieces of wood together. You’ll want to support your deck in the area where you’re planning to replace the post, just like for the repair. Then remove the bolts and screws from the joist at the top and knock out the post. Take your new post, secure it to the below-ground concrete footing, and re-attach it to the joist with the bolts and screws.

In securing your new post to the concrete base, you may have to remove the old bolt sticking out of the top and drill a hole for a new bolt. For this, you’ll need a masonry drill and a metal-cutting saw. There are also situations when you may have to remove the concrete base entirely. At that point, we recommend getting in touch with a decking installation expert here in Colorado. It’s also an excellent idea to have a professional look over your finished work to ensure your deck is safe, up to code, and ready to go for your next event.

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