How to Install an Exterior Door

Choosing a Door

The different types of doors that are available each have their advantages and disadvantages. The best door for your purposes will depend upon which qualities — aesthetics, durability, energy efficiency or economy — are most important to you. All door types are available with decorative glass. While most doors have insulated glass for energy efficiency, others may have beveled, silk-screened or stained glass with genuine brass caming (joining strips for segmented glass).

Wood doors are popular primarily because of the way they look and feel. Naturally finished hardwood doors with decorative glass are among the most elegant and expensive available. Wood doors can be either stained or painted. One disadvantage of wood is the fact that it shrinks and swells with changes in the weather. Engineered wood doors have laminated cores to reduce the potential for these problems, but the finish on all wood doors must be maintained to prevent damage over time. Wood doors are also generally heavier, which may make handling prior to installation a bit more difficult.

Steel doors are the most popular type. They have a core of foam insulation and are very energy-efficient. They are also highly resistant to shrinking, swelling, warping or splitting. On the other hand, they don't have the same aesthetic qualities and character as wood doors.

Fiberglass doors boast many of the advantages of steel, with the added advantage that they may be stained to approximate the look of a wood door. They're more expensive than steel doors, however, and still fall short of the look and feel of wood.

Installing the Door

The following illustrates the general principles involved in the installation of a pre-hung exterior door unit. Installation instructions may vary slightly among manufacturers. Always refer to the manufacturer's instructions as the authority for the door assembly you choose to install.

Preparing the Rough Opening

Remove the new door assembly from the packaging. Some doors are secured for shipping by screws installed through the jambs into the doors. For these units, the screws should be removed at this point. Other units have shipping braces that shouldn't be removed until the door is shimmed into the opening.

Remove the existing door and frame down to the rough opening (if applicable).

Assure that the rough opening is plumb and that the subsill (the floor under which the door sill will rest) is level. Level the subsill if necessary by using a beveled board or shims. A spacer board may be necessary if the door must clear an unusually high floor surface, such as very thick carpet.

The rough opening should be at least 1 inch wider and taller than the outside frame dimensions of the door system to be installed.

Apply two generous beads of caulk along the subsill an inch inside the front and rear edges of where the sill will be placed. Extend the caulk a couple of inches up the sides of the rough framing.

Placing the Door

Place the door into the opening. Put in the bottom first with the top facing outward toward you, then tilt the door into place.

Center the door in the opening and shim the frame tightly in place at the very bottom of the rough opening.

Squaring and Securing the Assembly

Now that the door is roughly in place, shim the rest of the door frame as necessary to hold it in place. During this step, place shims on the hinge side of the door behind any hinge attachment points in the door frame. The door will be permanently attached to the rough opening at these points later.

Adjust the shims and frame assembly until the jamb on the hinge side of the door is plumb in both directions. There should be a constant gap (about 1/8 of an inch) between the jamb and the edge of the door.

After making these adjustments, temporarily nail the door in place with 16d finishing nails through the hinge jamb near the hinge locations. Don't drive the nails all the way in.

Remove any shipping braces from the door, then open and close it to test its operation. It should operate freely.

From outside the house with the door closed, make sure there's an even contact between the door face and the weather stripping attached to the frame opposite the hinge jamb. Make any adjustments if necessary by adjusting the jamb in or out at the top or bottom.

From inside the house with the door closed, examine the edges of the door. Adjust the lock-side jamb until there's an even gap (about 1/8 of an inch) all around between the door edges and the faces of the jambs.

Install a solid shim behind the lock strike location.

Permanently secure the jambs. Begin with 3-inch screws driven through the shims at the hinge locations on the hinge jamb. Continue around the door, securing the remaining jambs with screws or nails (as recommended by the manufacturer) driven through shims. Install the screws or nails through the shims to prevent distorting the door frame by putting pressure against an unsupported area. Check the door occasionally as you perform this step to assure that the door assembly remains properly adjusted. Install screws through the shim at the lock strike location.

Finishing the Job

Insulate around the edges of the door frame with loosely packed fiberglass insulation or low-expansion foam. Foam that expands too much could distort the door frame inward, impeding the operation of the door.

Install the interior trim per the manufacturer's instructions. Caulk all joints and intersections of the trim and brick mold, particularly along the joints where the brick mold meets the exterior wall, with paintable caulk.

Install the weather strip at the base of the door as instructed by the door manufacturer (if necessary).