Most interior doors are prehung, which means their frame has already been attached to their casing for easier installation. This makes the process of finding and installing new doors much simpler.
Before installing your new door, double check that its rough opening is square and ensure the jack stud (stud on the inside wall near the header) is plumb.
Shims
Shims are an easy and cost-effective solution to ensure that doors fit tightly within wall openings while opening and closing smoothly. Shims make an immediate and noticeable impactful difference to how a door looks and operates, improving both appearance and functionality.
Shimming will be necessary when installing your new door if your rough opening is out of alignment with its trimmer stud (the closest stud to the frame that supports header above jamb). Otherwise, opening and closing may cause it to hit either the ceiling or pull away from its frame, requiring extra adjustments as it closes or opens.
Thin cardboard makes an excellent shim as it won’t split when driven screws into it, or compress when tightening hinge screws. Place one behind each of the three hinges starting with the top one and working down toward your door’s centre hinge. Be careful when hammering these in so as to not knock your door out of plumb as you work!
Hinges
With help from your friend to stabilize the door, use a screwdriver and hammer to carefully remove hinge pins with screwdriver. Carefully pull away from frame then set aside.
Once the door is installed, use a level to make sure its jamb sits level with wall framing. If necessary, slip wood shims under hinge side until its bubble aligns with latch side on level; once adjusted tack 8d finish nails through shims into trimmer studs for additional support.
Pre-hung doors typically include both jambs and casing, or molding that encases the frame. If your existing casing remains attached to its framing, simply nail it to it using a claw tack hammer, otherwise install new casing and caulk any gaps between it and your door frame for the best possible finish. This first step toward making your new entryway complete.
Casing
Pre-hung doors are complete units consisting of a slab door and its frame, requiring less labor than traditional slab doors but still need to be adjusted to fit and function correctly. Before installing one, an extra pair of hands should take a close look with a level for an accurate set up that achieves smooth operation with all components level, plumb, and square.
To do so, position the door in its opening and examine its “reveal.” An ideal gap would be one-eighth inch wide.
Shim the side jambs and studs as needed, using shims under the head jamb until it is also level with the wall. Install a bead of caulk around the sill to protect from water seepage, before installing either recycled casing from an old door or new trim and attaching latch/deadbolt units with draft preventer sweeps as a final step.
Finishing
Once the shims are secured in their places, install the casing to the frame and nail it securely in place on jambs and studs with a nailer. If your door includes backplate, strike plate and lockset components then follow their manufacturer’s installation instructions accordingly – now your project can be complete!
Stain the pre hung door and frame to match your home decor. Begin by applying primer to prep the wood surface, and once dry apply a coat of stain. Let it set before reinstalling hinges, latches, and hardware.
Before purchasing a new door, draw out a rough sketch of its opening to ensure you purchase the appropriate size. Measure both width and height to make sure it measures between two to 2.5 inches larger than your pre-hung jamb door’s jamb. Accuracy with measurements can make or break your project; double check everything and consult with professionals as necessary if needed.