One of the easiest ways to install or replace a new door in your house is to use a pre-hung door. A Pre-hung door comes in its own frame, ensuring that the door will easily swing and work as needed, which is its most important function.
Tips for Installing a Pre-Hung Door
To install this with a perfect fit, follow these instructions to put that new door into place!
Here are the tools you will need for this project:
- Shims
- Knife
- Angled Finish Nailer (Brad Nailer)
- Electric Drill
- Multi-Purpose Tool
- 3-inch Screws
- 4-to-6 foot Level
- Reciprocating Saw (Sawzall)
Step 1: Remove the door trim and the door itself
Score along the side of the door trim (what we commonly think of as the paneling that frames the door) with a blade to loosen and remove it. Do this on both sides so that you can access the door jamb behind it.
Remove the door and the hinges by taking out the screws.
Step 2: Remove the door jamb
Extract the door jamb, the part of the door frame that interacts directly with the door. The fastest, most recommended way to do this is to use a reciprocating saw or a Sawzall to cut the jamb in half and remove the pieces.
Remove any screws that attach the jamb to the structure of the house. You will usually find them close to the door hinge area or near the strike plate, which is the plate that interacts with the bolt of the doorknob.
Step 3. Remove the threshold (if the door has a threshold)
Some doors have a metal plate underneath the door called the threshold that people walk over. You will want to remove that during this process.
Step 4: Prep the Pre-Hung Door
Remove the prehung door’s cardboard packaging. Then dry-fit the door, which means just fitting the prehung door in the door opening to make sure it will work. If any of the sides of the frame are too long, you will need to adjust the frame by making cuts.
In our example, the door and frame are ¼ inches too tall, so the frame is hitting the door. So the frame was marked ¼ inches off the end on both sides, and we used a multipurpose tool (a skill saw is also recommended) to cut off the excess of the frame.
The multi-purpose tool can also be used to cut anything around the door frame so that it fits.
Insert shims at the bottom of the door frame if it needs a lift into the proper position in the door opening. In this case, a ¼ inch shim on both sides of the door frame was needed to prop the door to its proper place.
Step 5: Insert shims on the hinge side of the door to make the door frame plumb and level
Check to see how vertically straight (plumb) and how horizontally straight (level) the hinge side of the door opening is.
By seeing how far off from vertically straight the hinge side of the door opening is, we will know how much the door side will need to be adjusted by shims or small blocks of wood used to adjust the frame.
Using a four or six-foot level as a straightedge, set it against the jamb on the hinge side of the door and notice any gaps between the jamb and the straightedge.
Wherever you see a gap, that is where you insert a shim between the jamb and the drywall to straighten the jamb and close the gap and make the door jamb square.
You will most likely insert those shims just below the hinges.
Step 6: Secure jamb and cut off shims
Once you get the jamb on the door hinge side plumb, secure each shim to the jamb with a couple of nails from an angled finish nailer (also called a Brad nailer). Then, cut off the excess shims off the side of the jamb.
Step 7: Start shimming the strike side of the door to make the reveal (the gap between the door and the frame) consistent
After making sure that the hinge side of the door is plumb and level, the next step is to check the reveal to ensure a consistent gap all the way around the door, including the strike side of the door (where the doorknob is) and the top of the door.
If it is not consistent, double-check to make sure the hinge side is plumb and level again before beginning to shim on the other side.
Then, insert shims along the strike side of the door, ensuring that the reveal between the frame and the door is consistent. Start from the top of the door and move towards the bottom.
As you go down, ensure there are shims above and below the strike plate to reinforce and strengthen that area.
Secure each of the shims with a brad nailer and get off the excess shims.
If you want to make slight adjustments, you can use a wood block and a hammer to tap the jamb or the door stop in the desired direction.
Step 8: Shim the top of the door and make sure the reveal is consistent at the top
Now, do the same thing at the header (the top of the door) and insert shims where the gap between the frame and the door is less than level.
Again, secure each of the shims with a brad nailer and get off the excess.
If you want to make slight adjustments, you can use a wood block and a hammer to tap the jamb or the door stop in the desired direction.
Step 9: Test the door
Swing the door to make sure that it swings freely without obstruction. In our case, it swings ¼ inch above the floor to prevent backdraft in the case of fire.
Step 10: Install the door casing (door trim)
Now, cover up the shims with the trim.
Decide how far back you want the trim to set from the jamb. In our case, we are going with a 3/16” reveal. Mark that distance all the way around the jamb to show where the trim will sit.
Measure the corners that you marked. This will be considered the shorter distance of the trim, and you will need to make a mitered joint cut at a 45-degree angle to ensure that the angled cuts will line up at the corners of the door trim.
Install the header piece first and secure it with a brad nailer. Once that is secured and in place, use the points at the section of the header trim to determine the measurement of the trim at the sides of the door.
Cut the needed measured trim and install. If needed, do this for both sides (different rooms) of the door and make sure that the reveals between the door jamb and the trim are consistent
Step 11: Install the doorknob and strike plate
This project is now complete!
For more information on our Home Modeling Series, check out our videos on our YouTube channel or our other articles here at the Best Online Cabinets blog!
