Installing Exterior French Doors

French doors are an alternative to the traditional sliding patio door. French doors are a set of double doors made of wood, with glass panels. If you want to install a set of French doors in your home, follow the instructions below.

Measure the Space

As with all door replacement schemes, before you purchase any French doors, you should carefully measure the area where you intend to install the doors. Any kit that you buy will have to fit into this gap, although most patio doors are cut to standardized sizes, so you should be able to find a kit that fits your gap. Remember to include any framing in your calculations. If you need part of the wall removed, or you are fitting a patio door where there was only a basic door previously, you should call in a professional builder first.

Prepare the Space

You can find most French door kits in home improvement stores or hardware shops. These kits will often be pre-hung, which means that the door and frame come as a pair so you don't have to install each item separately. You can also find additional models and colors of French doors online, or you can order them from the store. Once you have obtained your kit, remove all of the packagings, and lay out the pieces. Remove the old door (if you had one) and caulk the area thoroughly. Leave it to dry.

Install the New French Doors

Once the caulk is dry, you should add any 2x4-inch boards needed to cover excess space; then center your new French doors in the gap. Get help in holding them upright and then slide the pre-hung French doors into the threshold, bottom first. You may need to tap the top of the frame slightly in order to get the doors to fit completely in the hole. After you make sure the doors are level, screw two or so temporary nails into the doorjamb. Use a spirit level to check that the door is plumb in the hole. Then screw your unit tightly into the opening.

Finish

Once you have secured your French doors, caulk around the edges of the frame and add insulation to the sides. Caulk around the outside of the French doors and also over the insulation. Install any molding to cover the edge of the doorframe and caulk any gaps in both the exterior and interior joints. Use 100 percent silicone caulking, as this will ensure that the door frame is waterproof and will also help the exterior caulking to prevent air from escaping. Check that the new French doors can move freely.