How to Install Fiberglass Doors

What You'll Need
Fiberglass door
Pry bar
Reciprocating saw
Nail cutting saw blade
Nail gun
Carpenter's level
Plywood (optional)
Measuring tape
Foil tape
Adhesive aluminum tape
Tin snips
Masking tape
Caulking gun
Cedar trim
Sill support

Fiberglass doors make for a great choice when you are replacing or installing a new door. Most of the heat loss from your home comes from the entrance door being of poor quality. Fiberglass doors are filled with foam which helps to insulate the home from the elements. The information that follows will show you how to properly install fiberglass doors.

Step 1 - Remove the Old Door

Before you can install fiberglass doors you will have to remove the old one. Use the pry bar to remove wood trim from around the door. The trim hides the actual door frame from view. You will have to remove the trim from the outside as well as in the inside of the home. The old door is most likely attached to the frame of the house through the door frame using nails. These are nearly impossible to remove so the best solution is to cut through them using the reciprocating saw. Now that all of the trim is removed and the nails cut the door frame can easily be removed from the home.

Step 2 - New Door Preparation

Doors are typically constructed to be the same basic sizes. This, however, does not mean that your house is suited for the door you chose. The most important factor is that the surface threshold is flat and level. You want to make the door fit to your needs. The odds are that the door frame is larger than the door. Use the tape measure to determine the size of the door in comparison to the house frame. Use planks of plywood to build the area to the right size and nail in place.

Step 3 - Seal the Frame

Place foil tape above the door under the trim and fold it then tape in place. This will create a watertight seal. Place aluminum tape around the sill a few inches up the sides then fold the tape over after cutting the corners. Place another strip of aluminum tape at the top of the sill. Attach the sill support to the frame. Cover the piece of metal with the cedar trim and nail in place. Apply silicone to the edges of the sill to prevent moisture from entering the bottom of the frame.

Step 4 - New Door

Place the new door on top of the silicone sealant. Nail in place temporarily. Use a level and make sure the door is properly seated and square with the frame. The gaps present between the frame and the door need to be uniform top to bottom. Open and close the door to test the fit. Finish nailing the door frame in place from outside. Install the flange with galvanized nails through the frame. Cover the top of the flange and sides with aluminum tape. Install the wood trim around the door both inside and out. Finally, you can now add the door hardware.