It is important to properly maintain your doors and the openings around them. This is critical when the doors are exposed to the elements. It is even more critical when there is little or no overhang protecting the door. If the rain can blow against the door or splash up against it after hitting the ground the risk of damage is greater.
The caulk around the door is instrumental in keeping the water out of your house. The caulk at the junction of the door jambs and the door sill is also very important. When water reaches the bottom of the door or its jambs it must go somewhere. The door sill is usually slanted from the house out. There might also be a slight tilt from side to side. Expansion and contraction, moisture or installation issues can result in this.
If the water can't travel to the edge of the sill and fall onto the stoop it will find another way out. If it goes to the ends of the sill where the side jambs meet the sill it might find its way under the sill. Caulking at this junction help prevent that from happening.
If you view the slide show above you will see what the consequences of having a small leak for a long time can be.
There was a crack where the side jambs met the sill. Water went under the side jambs and the wood sucked it straight up into the jambs. The wood rotted under the paint and the crack grew. I'm sure you've seen it. Rotten side jambs. Now more water could get in and instead of just going up into the jamb wood it went behind the flashing and rotted everything.
IT WAS NECESSARY TO REMOVE THE DECK TO MAKE THIS REPAIR.
You can see that the band board, joist ends, sub-floor, bottom wall plates and everything else was affected. Remember that the door itself is actually at the interior edge of the wall. Door pans and multiple barriers of flashing can prevent this. Caulking the outside is instrumental in preventing the water from getting under the jambs in the first place.
Caulking doesn't last forever. Even if you use a 30 year caulk it doesn't mean that the seal will last that long. Expansion and contraction of the wood due to temperature extremes will break down the seal. Most likely you painted the jambs. If the paint cracks water can get in and the moisture will accelerate the process.
CHECK THE CAULK YEARLY
Don't wait!! If you don't know what to look for call us. The cost of a service call can save you thousands.