How To Install A Prehung Exterior Door

Installing a prehung exterior door not only enhances the beauty of your home, with today's quality built doors,it also provides you with an added measure of safety and peice of mind.

There is an old expression concerning being judged by a first impression and that is especially true when it comes to your home. If you have just purchased a home or have been in your home for years and what to give it a much needed face lift, the first, best place to start is with the front door.

Today, not only do you have a wide choice of styles to fit you taste, but now exterior doors are available in an even wider choice of materials as well.

Let's take a look at what's available.

The different types of doors which are available each have advantages and disadvantages. The best door for your purposes will depend upon which qualities""aesthetics, durability, energy-efficiency, economy, etc.""are most important to you. No matter which door type you choose, all are available with decorative glass. Most doors have insulated glass for energy efficiency.

Wood doors"" Wood doors are popular primarily because of the way they look and feel. Traditionally they have come to convey the warmth of wood and provide a feeling of heavy sturdiness. Naturally finished hardwood doors with decorative glass are among the most elegant and as you would expect, the expensive available. How you finish a wood door is really up to you, Wood doors can be either stained or painted. The disadvantages of wood include the fact that they are subject to shrinking and swelling with changes in the weather, because of this wood doors generally carry only a 10 year manufacture's warrantee.

Steel doors"" Without doubt, steel doors are the most popular type on the market today. They have a core of foam insulation and are very energy efficient. They are also highly resistant to shrinking, swelling, warping or splitting and normally carry a 25 year manufacture's warrantee. But, on the other hand, although they are available in a wide array of styles, from simple to elegant, they don't have the special aesthetic qualities or character of wood.

Fiberglass doors"" doors boast many of the advantages of steel, and many fiberglass doors are now being manufactured with a "porous fiberglass" and will take most any wood gel stain giving them the added advantage that they may be stained to approximate the look of a wood door. True, they are more expensive than steel doors, however, the fiberglass exterior door brings the homeowner a door that will quite literally out last the house. You will find that fiberglass doors carry a Lifetime manufacture's warrantee.

Installation of Exterior Doors

Now we come to the scary part, installing that exterior door that you have found would be perfect for your home. Professional installation of an exterior door can run as high as $500.00, depending on the your area and the type of door your choose.

But, it is also a job you may be able to do yourself. The first step is overcoming the psychological hurdle of temporarily creating a hole in your house that is open to the outdoors.

Once you have done this, take a deep breath and dive into that door replacement project. Also, do remember that exterior doors are likely to be heavier, and so a helping hand would make the project progress more smoothly.

Here's what you'll need;


level, hammer, tape measure, caulk gun, and a screwdriver with phillips bit


butyl caulk, wood shims, 16d finishing nails, 15 #8 screws, and 3 inches long foam/fiberglass insulation acrylic latex caulk

All are readily available at you local building materials center.

Prepare the rough opening

Remove the new door assembly from the packaging. A good rule of thumb is to consult the manufacturer's instructions for your unit.

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

Check to see 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. If the door must clear an unusually high floor surface such as very thick carpet, a spacer board may be necessary.

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

Apply two generous beads of butyl 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. Latex and acrylic caulk are not recommended for this step.

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.

You have done well. This would be a good time to take a break and prepare for the next phase of installing your door.

Square and secure 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. you will be permanently attach the door 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 inch) between the jamb and the edge of the door.

After making these adjustments, temporarily nail the door in place through the hinge jamb near the hinge locations with 16d finishing nails . Do not 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 is an even contact between the door face and the weatherstripping 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 is an even gap (about 1/8 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 driven through shims.

It is important that the screws or nails be installed 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.

We are almost there, just one more thing to do.

Finish it off

Insulate around the edges of the door frame with loosely packed fiberglass insulation or low-expansion foam.

Install the interior trim. Caulk all joints and intersections of the trim and brickmold, particularly along the joints where the brickmold meets the exterior wall, with paintable caulk. Finally, install the weatherstrip at the base of the door if necessary.

There you have it, you're done. Take a moment or two and stand back to admire your handiwork. Beautiful isn't it and what makes it even more special, is that you did it yourself.

© High Speed Ventures 2011