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How to Replace an Exterior Door?

How to Replace an Exterior Door?

All of us are aware of how an exterior door forms an integral part of every house. Not only does it offer security, but also it adds to the appeal of the house. Also, amid harsh weather conditions, they offer protection from infestation by pests and insects. 

But what happens when the front exterior door becomes old and breaks down. It calls for an immediate replacement, right? Here’s everything you need to know to carry out an exterior door replacement.

Tools required for an exterior door replacement:

  • 2 feet and 4 feet levels

  • Caulk gun

  • Hammer

  • Flat screwdriver

  • Miter saw

  • Pry bar

  • Reciprocating saw

  • Set of nails

  • Tape measure

  • Utility knife

Materials required for an exterior door replacement:

  • Compulsory requirements 

  1. A roll of self-sticking, flashing, flexible membrane

  2. Backer rod

  3. Deck screws measuring 3 inches

  4. Drop cloth

  5. Finish nails of sizes 4d, 6d, and 10d

  6. Galvanized casing nails of sizes 10d and 16d

  7. Minimal expanding foam

  8. Polyurethane caulk

  9. Roll of flexible self-sticking flashing membrane

  • Optional requirements

  1. Transition molding

  2. Treated lumber for building up the sill

Step by step guide for replacing an exterior door:


  • The measurement of the old door is to be done

  1. In the majority of cases, a new door having the same size as the old, existing one can be ordered. 

  2. In case you're looking for altering the size, the frame of the opening needs to be readjusted. 

  3. Also, many more details such as the new door size, jamb width, rough opening, and exterior opening need to be recalculated and pitched in accordingly.

Step 2

  • The old exterior door is to be removed

  1. This can be accomplished by tapping the hinge pins with a set of nails and a hammer to make them loose. 

  2. This way, the door can be flung open and lifted off. 

  3. Ensure protection of the floor with the help of a drop cloth as usually old doors can be very heavy.

Step 3

  • The old trim needs to be pried loose

  1. This is the step where the interior trim is to be pried and loosened from the door frame. 

  2. Ensure the adjoining wall is protected from damage using a wide putty knife. 

  3. If you’ve got a plan of reusing the trim, the intersection between the molding and jamb has to be scored in the beginning with a utility knife.

Step 4

  • The old trim needs to be pried off

  1. This can be achieved by slicing the caulk joint between the side brick and exterior door trim. 

  2. Next, the trim is pried off from any contact with the doorjamb with the help of a pry bar.

Step 5

  • The jambs have to be removed

  1. This is done by completely cutting through the side jamb using a handsaw. 

  2. Use the pry bar to make the jambs loose and get them pulled out of the opening. 

  3. If you intend to reuse the interior moldings, the nails have to be pulled and extracted through the backside. 

  4. This can be gently carried out by a nipper or pliers to avoid any damage to the face. 

  5. When you cut through a single side jamb, it makes it easier to smoothly tear out the whole frame.

Step 6

  • The exterior door sill is to be prepared and installed

  1. Initially, the sill area needs to be checked with a 2 feet level. 

  2. Define the exact height of the sill so that the newly replaced exterior door clears off the space taken by a carpet or rugs while it swings in the inward direction. 

  3. Next, get the sill area built up with treated lumber to attain the desired height. 

  4. This will be followed by the addition of shims for properly leveling the sill while keeping a separation of around four inches. 

  5. To run a test fit, position the new door in the opening. 

  6. Make sure the casing perfectly fits against the siding. 

  7. Even though cutting the siding is a better option, it’s simpler and more practical to trim and finish the casing. 

  8. But, still, there may be areas in the casing that require trimming. 

  9. This is usually managed with a circular saw or belt sander. 

  10. Once the casing is thoroughly and accurately cleaned, coated deck screws will be used to fasten it.

Step 7

  • The flashing tape is to be installed

  1. Proper installation of flashing tape helps offer protection to the sill from water seepage. 

  2. The main objective lies in preventing the accumulation of water in the wood. 

  3. First, the rough areas of the sill will be covered with the flashing tape that sticks all by itself. 

  4. Then, allow the tape to be spread over the front edge and along the sides of the opening. 

  5. In the end, put the door in the opening, check its fit, and plumb it.

Step 8

  • The caulk will now be applied

  1. At first, see to it that the building paper remains in touch surrounding the edges of the frame. 

  2. When you’re certain that the door will perfectly fit, apply caulk behind the casing and along the sill. 

  3. Also, apply beads of polyurethane caulk at the sill and along the edges and top of the opening.

Step 9

  • The new replacement exterior door is to be fastened

  1. To do this, firstly, accurate leveling of the doorsill is to be ensured. 

  2. Secondly, fit in the opening with the top of the door and attach it with the help of galvanized casing nails. 

  3. Also, fastening of the bottom corners and plumbing of the jamb on the side of the hinge area to be ensured.

Step 10

  • The jamb on the side of the hinge is to be shimmed

  1. Do shim behind each of the hinges. In the case of larger spaces, begin with tiny plywood squares. 

  2. Then finish off with the pairs of shims. Also, make certain the hinge-side jamb is suitably plumbed.

Step 11

  • The jamb on the side of the latch is to be shimmed

  1. Here the main intent is to position the door perfectly in the opening and wedge the sides to make them look straight and plumb. 

  2. This can be executed by shimming the top, middle portion, and bottom of the jamb at the side of the latch and ensuring there’s consistency in the gap between the door and the doorjamb. 

  3. Next, the shims have to be scraped off with a utility knife. 

  4. When you pull off the exact fit, fix the jamb with a nail into the framing at all shim locations.

Step 12

  • The hinge screws need to be replaced

  1. This can be done by driving 3 inches deck screws into the framing. 

  2. Extra casing nails also need to be delved in every 16 inches along with the exterior trim through its sides and on top of it.

Step 13

  • A drip cap may be needed to be installed

  1. By and large, this is needed when the door comes directly in contact with inclement weather conditions. 

  2. Here, a metal drip cap helps eliminate water. 

  3. However, a new installation may be needed if the drip cap is lost or damaged. 

  4. This needs to be done before setting the frame of the door in the opening.

Step 14

  • Insulation around the door is to be accomplished

  1. For this, you may need two cans of minimal expanding foam to fill and insulate the space between the framing and door jamb. 

  2. Once the foam has evenly spread, any remaining space may be loosely stuffed with fiberglass insulation strips.

Step 15

  • The installation of the interior trim is to be done

  1. You can either reinstall the old, existing trim or remove it totally and install a new one. 

  2. In case a gap exists between the flooring and the newly planted sill, it can be covered using a beveled transition.

Step 16

  • The application of caulk and caulk backer is to be done

  1. In the beginning, the gap between the siding and trim is filled in by pressing a foam backer rod. 

  2. Next, a neat bead of caulk is applied to the gap. 

  3. Then, a trim board is cut to be secured underneath the sill. 

  4. Fasten it to the framing with screws. 

  5. Wider gaps need an insertion of a foam backer followed by caulk application. 

  6. Nearly all the doors need an extra trim board to be fitted under the sill for supporting its external edge. 

  7. Finally, paint or varnish the door, its jamb, and trim.


Thus by now, you know what to do if your exterior door looks shabby and worn down. Old exterior door replacement with a new one under the care and supervision of professionals from Florida Lumber can make things easy and plain-sailing for you.

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