If you want to install a pre-hung door in your house, you must understand how to do it correctly. It shouldn’t be too hard if you follow proper steps and follow through!
Before beginning, check that the handle on your existing door matches that of the new one; otherwise, trimming may be required to adjust for differences.
Measure the Rough Opening
Before ordering a new door, it’s essential to determine its current rough opening size. Remove all trim or molding around the door, measure its width from inside edge of left jamb to inside edge of right jamb and record the smallest measurement three times.
Once again, take measurements from the floor up to the header frame – three measurements total will suffice and record the lowest reading.
When installing the frame in an opening, be sure to measure equal spacing between door and jamb (known as reveal) on both sides (also called reveal). If any side has less room than expected, add shims for equalization. Also ensure the door and jamb frame is square to ensure your new door swings open in its intended direction and latches securely.
Remove the Existing Door
Pre-hung doors can add beauty and improve energy efficiency in your home’s entryway while increasing safety. Unfortunately, installing one takes both time and effort – it is wiser to hire professional services to take on this project.
First step of installation is removing old door and frame from hinges using long nails or screwdrivers inserted into hinge pins to pry them loose, or loosen with a hammer if pins do not release easily.
If the door opening is finished with drywall rather than casing and trim, you may be able to treat it like a framed opening. Check its squareness using a tape measure, using wood shims as needed if necessary, to restore balance to its frame.
Once the old frame has been taken down, install z-flashing around the bottom of the exterior sill to protect against water damage and apply caulk to seal any gaps between jamb faces and sill.
Install the Jambs
After making sure that the door is centered in its frame, add wood shims for stability. These thin pieces of wood — typically designed as tapered wedges — can be used for making adjustments during construction and woodworking projects, such as installing doors and windows. Shim the hinge side first before adding more on either latch side if necessary until all gaps between hinge and latch are level with frame; check regularly using a level to assess frame levels as necessary and add further shims if necessary.
Once your jambs are level, secure them to the rough opening with finishing nails or screws (#8 for hollow core doors and #8 2 1/2 finish screws for heavier doors) driven through shims into wall studs. Any shims extending past the edge of jamb should be scored with a utility knife before breaking flush with the wall surface surface; repeat this process on both sides of your frame frame.
Hang the Door
Installing a door that’s level, plumb and square makes the job of hanging one much simpler. If your home is very old, use a framing square to examine its corners; these might be higher or lower than expected and can cause the prehung door not to fit as expected in its frame.
Position the prehung door into its frame with assistance from another individual and ensure it opens and closes smoothly. If necessary, add shims under it until your level’s bubble is centered on its center line.
Once the door fits perfectly, secure its hinges and test its lockset in its holes. If not completely satisfied with how your new prehung door fits together, use putty (which comes in many colors) to cover nail heads or fill gaps between nailheads if necessary. It’s essential that accurate measurements be taken prior to purchasing new prehung doors; professional framing services should also be consulted when framing walls for new doors.