Removing the Old Door

• 1). Score the sealant attaching your door's interior wood trim to the wall with a utility knife or razor blade. This allows you to remove the trim without damaging the drywall beneath.
  
  
• 2). Wedge the flat edge of a pry bar in between the drywall and the interior door trim. Hit the exposed end of the pry bar with the hammer until it lodges well beneath the trim. Push down on the pry bar to pry the trim away from the wall. Repeat this procedure on all four sides of the door. Lift away the trim.
  
  
• 3). Remove your exterior door trim on both sides in the same manner. If you plan to install a pre-hung exterior door, remove the existing door frame by prying free any nails and cutting the frame into manageable pieces with a reciprocating saw.
  
  
• 4). Peel away the weatherstripping surrounding the door and discard it.
  
  
• 5). Remove the pins from the door hinges by wedging the flat edge of a flat-head screwdriver into the space between the pin and the door hinge. Tap the screwdriver handle gently with your hammer while prying the pin upward and out. Repeat the process until all of the door's pins have been removed. Removing the entire hinge is not necessary.
  
  
• 6). Lower the door carefully to the ground.
  
  

Attaching the New Door

• 1). Brace the bottom of your new door against the threshold and push it forward into the door frame.
  
  
• 2). Tilt the door slightly backward into your home. Have a friend or family member brace the door while you place the door pins into the hinges. If you are installing a pre-hung exterior door, maneuver the frame into position at the threshold and push the door frame forward until it fits snugly against the wall on all sides.
  
  
• 3). Apply a thin strip of silicone caulking around the door to secure the trim. Replace the exterior trim. If your exterior trim has protruding nails, hammer the trim back into the wall with the hammer. Repeat the process for the interior trim. For pre-hung doors, nail the frame into your home's exterior with finishing nails.
  
  
• 4). Hammer new nails into the reattached trim at each trim edge to keep it secure.
  
  
• 5). Apply caulking around any open gaps between the interior and exterior trim boards and the wall's surface. Wipe the fresh caulking smooth with a dry cloth.
  
  
• 6). Measure and cut new weatherstripping, using a tape measure and scissors. Glue or staple the weatherstripping into place around the exterior edges of the door. If you opt for wooden weatherstripping, nail it into place with nails spaced 12 inches apart and beginning two inches from each edge.