Door Frame Rot: Lots of Issues in a Small Area
While it is common for the outside trim of the door, commonly called the brick mold, to show signs of rot and water damage, it is not typical for the door jamb to rot out. The construction of a door jamb is designed to prevent water penetration into the wood jamb. This only leaves a few entry points into the wood. The easiest is from water sitting on the threshold of the door and seeping between the threshold and the door jamb. This amount of moisture takes many years to show wear and tear and usually only involves some surface rot. The most common form of wood rot on a door is from water penetration from the top of the door do to poor flashing, improper caulking, or improper installation of the door. The water penetrates above the door and flows in the space between the framing of the door and the door jamb. The water puddles on the bottom plate and the door jamb wicks the water into it causing it to become saturated. This process will cause a bubbling of the wood surface or paint on the interior of the door jamb. A simple probe test with a scratch Al or a screw driver will allow you to tell how extensive the damage is. In the picture above, I am able to stick the screw driver all the way through the door jamb. This causes a problems with door operation, door jamb strength, and insect infestation. This particular door had a nest of carpenter ants living underneath it, feeding on the soft, moist wood.
While this seems like a small problem, this rot can cause the door to shift, affect the structural framing, and invite mold growth into your home. The cost could be thousands from what is considered to be a fairly small issue.
The important thing to remember about rot is that it cannot be fixed. The integrity of the wood has been compromised and can no longer function as it was intended. Applying wood putty over rotten wood keeps the moisture in the wood from escaping and could actually cause more problems. When you encounter wood rot, it is best to remove the rotten portion of wood, or the entire piece and replace it.