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Steps to Install a Prehung Exterior Door

Steps to Install a Prehung Exterior Door

The Exterior door to your house may become damaged due to overuse or weathering effects. A damaged door lessens a home’s curb appeal and compromises the security of residents. Hence, it is essential to install a new front door that looks good and provides adequate security. In the past, you needed the help of skilled carpenters to install the door. These days, you can perform this task on your own with a little guidance using a prehung door.

Prehung doors are self-contained units, as they come with a frame, slab, and hinges. You are saved from manufacturing a door from scratch, as you need not measure or prepare a door slab from the wooden planks. You need not buy the hinges separately or attempt to manufacture the frame with the correct measurements either. Hence, these doors give you the ultimate peace of mind.


Prehung exterior doors have simplified the complex process of installation. The process does not require advanced carpentry skills, and you can execute the entire task using some basic tools. You can install a prehung exterior door with a basic knowledge of carpentry using an electric drilling machine, wooden shims, measuring tape, a hammer, a level, a nailset, a utility knife, an electric saw and spray foam insulation. You may even need a miter saw to replace the door’s interior trim.


  • It is essential to purchasing a new door before removing an old door. You need to measure the doorway opening’s height, width, and depth without the interior jamb before making any purchase. This allows you to buy a prehung door with proper measurements.
  • You need to remove the molding and frame of the old door before installing a new door. You can remove the exterior trim and insulation using a crowbar. You need to be extremely careful when using a crowbar, as excessive force can damage the doorway.
  • You can use a screwdriver or the hammer and nailset to remove the hinge pins from old doors. You need to take the hinges off the doorjamb and remove the screws of the door sill.
  • You need to test the new door’s fitting after setting it carefully with the attached shipping brackets. You can use the shims to keep the door steady. You may use a level and a plumb to measure the door’s alignment to the floor. You can mark a line across the top of the doorway opening and remove the door after finishing all measurements.
  • You even need to measure the subfloor’s level to make sure that the newly placed door clears the main floor. You may need to affix a plank of treated wood to the subfloor to raise its level.
  • You can place a thick lining of latex caulk along the bottom of the doorway before setting a prehung door in the center. You can insert the wooden shims at the top to keep the door level.
  • You can insert the shims in locations of the hinges while maintaining 1/8th inch clearance between the doorjamb and the rough frame. You need to drive screws through the shims while maintaining an even gap along with the door reveal. You also need to keep an even space between the door and jamb-stop when measuring from outside.
  • You can trim off the excess shims and test the door’s operation after removing all shipping braces.
  • You can seal the gaps around the frame using minimally expanding spray foam insulation. You can use paintable caulk to seal this gap on the exterior side of this door. You can use a putty knife to scrape off the excess insulation or caulk after drying.
  • You can install the finish molding using a hammer and nailset once the drying is complete.

The prehung exterior door is ready for the installation of any door hardware at this point.

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