Attach a new door bottom with an integral sweep.
How to seal exterior door handle side.
This is a simple solution to your problem.
If there are grooves along the threshold run a nail.
Screw a bristle sweep to the bottom of the door.
Examine the weatherstripping on the bottom of the door to see if there are holes or worn areas.
Cut metal tension strips to fit door jamb.
Drag the edge of a paint scraper along the top bottom and sides of the door and door frame to remove any stuck on.
Pull the weatherstripping toward the outer edge of the door.
This is what i particularly suggest for the front door to keep our.
After attaching a new door bottom seal the wood.
Place a pair of sawhorses over that dropcloth and place the exterior door on top of the sawhorses with the exterior side facing up.
Also clean the threshold which is the bottom of the door frame.