Wood garage doors are beautiful and often expensive, but they require more maintenance than most other garage door materials. This isn't to say that wood doors aren't sturdy, but they are affected by certain weather conditions and other problems more than other materials. Many problems that may require serious repairs or replacements happen due to old age or neglect, so with proper maintenance you can fix small problems and avoid big ones to keep your wood doors sturdy.
Keep Water Away From Your Doors
Even when properly sealed, wood doors can be damaged by water. A good sealant can keep water out temporarily, so your doors should be fine during rain and even in frequently humid environments. Long term, however, water can cause warping, cracking and rotting. The most common place you'll see this is near the bottom of the door, because water can pool up around the door and be absorbed by it. If the water around the door doesn't dry up, the water already inside the door can start to cause damage.
Catch Bending And Bowing Early
Because wood doors tend to be a lot heavier than other types of doors—especially wide ones—they can eventually start to bow. A bowing door tends to lean down slightly in the middle where there is the least amount of support, and is most noticeable when the door is open.
The good news is this doesn't mean you have a big structural problem. If caught early enough, you may only need to repair or replace the bottom part of the frame. This is usually enough to restore the door's shape, as the frame's weakness is the only thing letting the door bow in the first place.
Refinish When Necessary
Certain climates are harder on your wooden doors. Hot, dry climates and salt air climates can start to damage your door more quickly than others because they are harsh on the wood and finish. Refinishing can sometimes be a chore, but it can keep your wood protected for much longer. When you start to notice your finish fading or start to bubble, or if you start noticing any cracks in the wood, it's time to refinish.
When refinishing, avoid using urethanes and varnishes, because they don't let the wood breathe. Letting wood breathe is important so moisture doesn't get sealed in; if your door gets wet, it needs to be able to release the water too. If and when you decide to repaint, use an oil-based primer or exterior latex.
Protect Both Sides Of The Door
Your wood door's exterior bears the brunt of the elements, but it's important to keep the interior protected by a finish as well. The reason you should apply finishes to the inside is because it helps the exterior finish last longer; with changes in humidity, wood expands and contracts, and if only one side of the wood is finished, this can stress the finish and made it fade or crack more quickly.