Installing a pre-hung door in your house can instantly update the appearance of any room, providing it swings freely and closes nearly perfectly aligned.
If your carpentry skills are up to snuff, this project should be fairly straightforward. But if any challenges arise or issues surface early on, consider calling in professional help instead.
Shims
Prehung doors may seem straightforward for contractors to install, but to achieve perfection it takes basic carpentry knowledge and skill. Use a level or plumb bob to check that both wall surfaces and trimmer studs are level before adding shims underneath the side jambs (upright supports by which doors are suspended) until their head jamb (the top of the frame) is flush with the wall surface.
On the hinge side of your door, use a level to set its jamb so its bubble is centered between the floor and top of door casing. Repeat this process on both latch sides; close and check that reveal is even across door before making adjustments on shimming top jamb if needed to prevent future sagging; this step is particularly critical with heavy solid core doors than hollow core ones.
Jambs
Before installing your new door, use a level or plumb bob to verify that both hinge and latch jambs are plumb with each other and that their edges are square to the wall – this will help ensure the pre-hung door swings freely and catches evenly against weatherstripping.
If the hinge side of your door frame is out-of-place, add shims behind casing at all hinge locations before checking alignment using a level. If needed, repeat this process at each hinge location as necessary.
If the strike side of a door frame is out-of-plumb, shim it as necessary – however, be wary not to overshim as this can cause it to twist out of position when fastened.
Framing
Pre-hung doors may be easier to install than slab doors, but still require basic carpentry skills for successful installation. When placing pre-hung doors into existing openings, the first step should be preparing the frame by removing old door and jambs – this may prove challenging as solid core doors can weigh considerably more.
Utilize a screwdriver and hammer to unbolt the hinge pins, pry apart head and side jambs using pry bars, remove strike plate/hinged plates from frame as well as loosen trim with putty knife, then pry the strike plates/hinged plates off frame using putty knifes.
Once the frame is clean and ready for installation, use a level to check that it’s plumb, as well as check reveal gaps at the top and striker sides – these should match up perfectly with the rest of the frame; if not, adjust accordingly with shims until evened out. Furthermore, double-check that your floor surface in which you plan on placing the door is flat and smooth before proceeding further with installing your door.
Trim
Installing pre-hung doors and frames alone can be challenging, so having someone assist is invaluable for this task. If no one is available to assist, consider hiring a professional to mount your interior door.
A skilled carpenter should be able to complete this task in approximately 20 to 1 hour, depending on their skill level and appropriate framing. Before hanging a pre-hung door, ensure that its opening is square and level before doing the installation process.
To achieve this, first measure the width and height of the rough opening in your wall to make sure it’s large and level enough for your new door. If either of the sides are off by more than 1/2 an inch from plumb, shimping jambs may be required in order to bring them into proper position in order to hang a pre-hung door; otherwise a slab door might be more suitable in your home.