How to Install an Exterior Door

Installing a door in any home can be a challenge but believe it or not, anyone with a little time and instruction can tackle this project. Making sure to make correct measurements will be the first hurdle you must overcome.

First measure the width of the opening. This can be a challenge with a door already in place but measure from jamb to jamb and add ¾" to each side to get your overall width. Most standard doors are either 38 ½" wide or 34 ½" wide. These call out sizes are known as 3-0 and 2-8 in the door industry.

Next measure the height of the opening. Measure from the bottom sill to the top of the opening to find the overall height. Over 95% of doors are considered a 6-8 height and will measure out to around 81 ½". In older homes, make sure to measure carefully as some will have doors that are 6-6 height and will measure to 79 ½". If your home has 8' tall doors that will be evident from the beginning.

Now, make sure to measure the jamb width so that the new door unit will match the thickness of your wall. Standard doors carry either a 4 9/16" or 6 9/16" jamb. If your house is block construction, like mine, these will often have 7 ¼" or 8 ¼" jambs.

Once you have all of these measurements go to you local building supply and pick out a door that will fit your opening. Virtually every manufacturer will offer these options so you can customize your door to your opening.

When you get ready to install, there are very few tools you will need. Make sure you have these things handy: minimum 4' level, silicone caulk, shims, long #9 set screws, and a screw gun. Other tools may be necessary but the majority of doors can be installed using just these few tools.

First, dry fit the door into the opening. See how plumb the door sits in the opening and look for any major gaps. Also, throw the level on the side jambs to get a feel for how level the door sits without any shims in place. Remove the door unit and lay a thick bead of silicone on the sill of the door.

Once you have your caulk in place, sit the door back in and begin the final install. Shim the door on the hinge side first until it sits level. Run your set screws through the side jamb even with your hinges and check for level again. Once you have this side level and attached, put the level on the lock side. If necessary, shim underneath the sill to bring the lock side to level. Place shims on the lock side and screw approximately even with the hinges from the other side.

Now, test to see how the door closes. Make sure the slab is not rubbing on the frame at any point and that when closed there is no daylight showing around the slab. If the slab is rubbing on the lock side, run a long screw through the hinge corresponding to the rub. This should pull the slab back to center and allow it to swing free.

By following these steps almost anyone can install their own door and save a lot of money. Always make sure to measure for level numerous times and caulk the sill so your door will never allow air to draft in.