How to Spot and Repair Rotting Deck Boards

This time of year, a lot of inclement weather such as snow and rain come down from the sky and help our planet live. For the plants on this earth, it’s a natural cycle of life and death. Wood tends to rot excessively in these conditions. That’s bad news for owners of wood related products that are exposed to the elements, such as siding and especially decks. Many decks are built with pressure treated lumber, but even these can rot with time.

So what do you do when you think your deck may be in danger? This article describes how to spot potential problems, and how to take action to repair them the professional way.

Look around your deck for spots where heavy water damage may occur. Water builds up and pooling is a sure sign that rot is on its way in these particular areas, or that it is already occurring. Look for spots that are spongy or discolored. Is the wood grey or flaking apart? If so it’s probably water damage. Use a screw driver to check for soft spots in the wood. If the screwdriver sinks into the wood, then it needs to be addressed immediately.

If the damage is minimal, then simply scrape out the spongy and flakey wood with a paint scraper or large screwdriver. Clean the rotting wood away until it is hard and free from discoloration. You can also use a wire brush to help remove the old rot away. A sander works great for removing small blemishes, but if it goes deep, then it is possible to remove the rot with a handheld rotary tool such as a dremel.

Once the area is free from rot, you can fill it in with wood putty. Purchase an exterior wood putty that matches your decks wood color best. Using a small putty knife, fill the cavity with the wood putty. Let the putty dry for several hours, and then apply a second coat. After the putty dries, touch it up with some sand paper to remove the rough edges. You can paint or stain the dried putty to match the exterior of your existing deck color.

To fix larger problems like the decking surface, you will need to remove and replace the rotted wood. To do this, you will need a small hole saw and a drill bit the size of the hole saw itself. Locate the area where the joist is closest to the rotted board. You can do this by looking at where the nails or screws are. Sometimes you can peer through the cracks and see exactly where the joist is. Drill a small hole on the rotted board next to the joist as close as possible without drilling into the joist itself. Once the hole is drilled you can put the hole saw into the drilled out area and cut the board loose. Do this step on the other side of the board as close as you can to the rot nearest to the adjacent joist. Remove the board and throw it away. Buy a board of sufficient length and similar grade, species and color of the existing deck.

Cut the board to length. Scrub the board with a solution of 1 cup baking soda to 1 gallon of warm water. This will give the wood a weathered look and help match it with the existing deck. Cut a 2×4 around 12 inches long and put in two galvanized 10d nails. Nail the board flush to the joists where you previously cut out the decking board. This provides a nailer for the new deck board to be attached to. Align the new deck board with the old ones and nail or screw into place. Repeat this process for any other deck boards that may need replacing due to rot.