Checking for Deck Rot

Not only are rotting decks ugly but they can also be dangerous. Every year dozens of people are injured in accidents related to poorly constructed or rotting decks. Don’t let this happen to you and your guests.

Deck Components
Before you start looking for rot, it’s good to understand the different components of your deck. The key components are identified in the illustration below.


Here’s how to check for rot in your deck. Start by just walking around on your deck. Take bouncy steps. Any give or sway is cause for concern.

Take a Look
A visual inspection will reveal tell-tale signs of rot and decay. Look for dark spots in the wood. Look for crumbling edges. If there is mold or moss growing on the wood, be sure to dig deeper.



Poke Around
Use a sharp-tipped object such as a large nail or a small Philips screwdriver to test for rot. If you’re unable to get underneath your deck, poke into the joists between the decking boards to feel whether or not the wood is soft. If the support beams are not covered by a fascia (face plate), poke them as well. If your deck has a fascia, remove one or two of the boards to better access the beams. You may also want to remove a decking board or two for better access to the joists. Be sure to test the bottoms of any posts.

Any wood that gives easily to the tip of the pointed object has gone bad.

Remember, wood will rot from the moisture side – rain on top, soil on the bottom. Although dark wood often indicates rot, light-colored wood may still be hiding rot underneath.

Check the Ledger
Even if your beams and joists are in great shape, they may be attached to a rotting ledger (the board along your house to which the joist hangers are nailed). Even if your deck was repaired or rebuilt at some point in the past, it’s possible that it was attached to the original ledger. If the ledger didn’t have flashing installed to prevent exposure to water, it could very well be rotting away relatively unnoticed. This is a recipe for disaster! The joists could pull away from the house and the entire deck could go down.

Preventive Maintenance
If everything checks out OK, it’s a good idea to put your deck on a scheduled preventive maintenance plan to ensure that it lasts as long as possible. Regular power washing will help keep mold and moss from growing. Follow the power washing with a fresh coat of stain/sealer to keep the moisture out. Generally, in the Midwest, it’s a good ideal to power wash and stain/seal a deck about every three years.

Nebraska’s winters can be hard on decks. Another trick to get more life out of your deck is to shovel the snow off of it. As if shoveling the snow on your driveway wasn’t enough! Unfortunately, when snow sits on a deck, the moisture doesn’t run off as it does when rain falls on a deck. Use a plastic snow shovel to avoid damaging the deck’s finish.

With proper preventive maintenance, a deck will provide years of enjoyment. Without the proper maintenance, a deck can become a major accident waiting to happen. In addition, rebuilding a deck can easily cost seven to ten times what it costs to power wash and stain/seal the same size deck.
An ounce of prevention …