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Project Guide

How to Install an Exterior Door

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Measure and Prepare the Door Opening
A man measuring an entry door

The first step you need to accomplish before you learn how to install an exterior door is that you must prepare the rough opening of the door. Make sure the door swing direction and handle placement is what you need before removing the new door and frame from the packaging.   

When selecting a door, you'll need to know the "handedness" of the door. An easy way to do this is to simply open the door. Stand in the doorframe with your back along the hinges. If the hand by the doorknob is your right, it's a right-handed door. If it's by your left, you have a left-handed door.

Keep these tips in mind: 

  • Leave the retaining brackets in place that hold the door closed while you’re working on it.
  • Measure both the door and rough opening to make sure the door is the right size. 

Installing an exterior door that is insulated and made of steel can be heavy and cumbersome due to the weight of the materials. If you choose to install an exterior door made of steel, you will need a helper. Certain wood front doors will also be heavier than others, so take that into consideration before starting this project.

Center and Test-Fit the Door and Frame
A man test fitting the frame of a home entryway.
  • Center the door and frame in the rough opening as a test-fit.
  • Use a level to make sure the door is plumb.
  • If necessary, shim under the lower side jamb until the door is plumb.
  • Adjust as necessary to keep the door jambs square with each other.  
  • Double check to make sure the door is centered.
Trace the Moulding
A man adjusting the moulding on the frame of a home entryway.
  • Trace the outline of the moulding onto the siding.
  • If you have vinyl or metal siding, be sure to enlarge the outline to make room for the extra trim required.
  • Remove the door and frame after finishing the outline.
Cut Along the Outline and Cut the Drip Edge
A man caulking the frame of a home entryway.
  • Cut along the outline down to the sheathing.
  • With your safety glasses on, start the cut with the blade clear of the siding, and then lower the moving blade into it.
  • Stop just short of the corners to prevent damaging the siding that will remain.
  • Finish the corners with a sharp wood chisel.
  • Cut a piece of the drip edge to fit the width of the rough opening.
  • To provide a moisture barrier, apply building paper to the exposed areas of the walls and door frame.
  • Cut the drip edge to fit the width of the rough opening and slide it underneath the siding at the top of the opening.
  • Do not nail the drip edge.
Check the Fit
Two men installing a new entry door on the exterior of a home.
  • Check the fit before installing a new door, and enlarge the opening as necessary.  
  • Once you are satisfied with the fit of the door, remove it and apply several thick beads of silicone caulk to the bottom of the doorsill.
  • Caulk underneath the spots where the bottom of the jamb and brick moulding will be.
Center the Door
Two men securing a new entry door on the exterior of a home.
  • Center the door in the rough opening.
  • Push the moulding tight against the sheathing.
Check the Door Jamb
A man shimming a new entry door inside the home.
  • Check that the door jamb on the hinge side is plumb and shim as necessary.
  • Temporarily screw the hinge jamb in place by driving two #8 3-inch drywall screws through it: One about 2 inches above the top hinge and the other about 2 inches from the center hinge.
  • Loosen the screws if necessary to bring the jamb back into plumb.
Cut Shims
A man applying shims to a new entry door inside the home.
  • Cut pairs of wedge-shaped cedar shims together to form flat shims.
  • Using another entrance, go inside and insert them into the gaps behind the hinges and between the jamb and framing to stabilize the jamb.
  • Cedar shims are preferable to pine because they are more weather-resistant.
Install the Hinges
A man drilling hinges into a new entry door inside the home.
  • Install the door hinges provided by the manufacturer.
  • Secure them to the frame with the included hardware.
Remove the Retaining Brackets
A man securing a new entry door outside the home.
  • Remove the retaining brackets installed by the manufacturer.
  • Open and close the door to make sure it works properly.
Install New Anchor Screws
A man securing the bottom of a frame on an entry door to the home.
  • Remove two of the screws on the top hinge and replace with long anchor screws. These anchor screws will penetrate the framing members to strengthen the installation.
  • Do not use longer screws than the manufacturer calls for on doors with sidelights — the screws might break the glass.
Anchor the Moulding
A man anchoring moulding inside the home.
  • Anchor the moulding to the door frame with 10d galvanized nails every 12 inches.
  • Use a nail set to drive the nail heads below the surface of the wood.
Apply Caulk and Adjust the Threshold
A man caulking the exterior of a new entry door.
  • Apply paintable caulk and insulate around the entire door frame.
  • Fill all nail holes with caulk and insulate with weather stripping where applicable.
  • Finish the door as directed by the manufacturer.
  • Adjust the threshold for a tight seal (as long as it is adjustable) as directed by the manufacturer.

Tip: If you set the threshold too high, it will make the door difficult to open and eventually could damage either the door or the weather stripping.

Replace the Casing and Cut the Shims
A man nailing trim on a new entry door.
  • If the trim was damaged during removal of the old door, cut and install new casing.
  • Cut the shims flush with the framing using a utility knife.

Install A New Lock and Knob
A man installing a door knob and safety lock on a new entry door.
  • Install a new door lock and door knob by inserting the latch through the hole for the new parts.  
  • Insert the lockset tailpieces through the latch bolt, and screw the handles together by tightening the retaining screws.
  • Avoid damage to the screws by using a hand screwdriver. 
  • Complete the installation by attaching the strike plate to the door jamb to fit the latch bolt.

Learning how to install a prehung door makes it simple to upgrade your exterior door. If you're looking for exterior doors and more, The Home Depot delivers online orders when and where you need them. You can also rent the tools you need from us.