Installing new prehung doors in your house can add a fresh new look. Unlike standard slab doors, prehung doors come complete with frames and hinges already attached for installation.
To ensure the door fits securely, shim the hinge side and latch side of its frame accordingly to ensure an even and uniform rough opening. This should help ensure an ideal experience!
Measure the Opening
Pre-hung interior doors should always be fitted into rough openings that allow enough clearance. Otherwise, they could scrape on the floor or become stuck as they open. When creating your rough opening frame for this pre-hung door, add two inches when framing its dimensions.
Remove the interior trim and measure its opening from stud to stud; write down the smallest measurement. Additionally, you can take steps such as dismantling hinge jambs to check that trimmers are plumb and square with wall with the use of a level.
Place a level on the strike side of the jamb and adjust shims so that the bubble sits in the center of its frame (known as reveal). Repeat this step on latch side as well.
Cut the Jambs
Once the jambs are shimmed, ensure they’re all of uniform length, and secure them to the door frame with finish nails. Next, cut a head stop to fit inside width of side stops before nailing it securely into position.
Use a level to ensure the top and sides of your frame are plumb and level, as well as framing square to check whether trimmer studs are square to the wall.
Once your casing has been attached to its frame, putty is an effective way of hiding screwheads. Available in multiple shades and textures, there should be something suitable for your door’s color scheme.
Shim the Jambs
Doorjambs that come pre-equipped with casing should be fastened securely to wall studs using shims to ensure a flat surface for later installation of casing.
To ensure that the head (top) jamb is level with both the king stud and hinge side jambs, place a 4-foot level on the floor in the doorway and adjust shims until its bubble is centered. Secure these shims to the framing using 2-1/2 inch finish nails.
Care must be taken not to add too many shims as this may alter the alignment of hinges when closing the door.
Install the Jambs
Time and money savings can be achieved by opting for pre-hung doors rather than replacing an existing frame, especially if your existing frame is in good condition and you plan to keep it.
Slide the hinge side jamb into position and ensure it is flush with the stud before using wood shims to secure it until a consistent reveal all around your frame can be achieved. Use a level to check all of your reveals, continuing shimming until all side jambs are plumb.
Head Jamb – Shimming the head jamb isn’t necessary since its casing will hold it in place. Nail through any shims on either frame side and some on hinge side in order to strengthen them and ensure a tight fit.
Install the Door
Pre-hung doors differ from slab doors by including doorknob cutouts, frames and hinges for easier installation. Although it takes longer, pre-hung doors provide smooth opening and closing action when used correctly.
Before installing the door, lay a 4-foot level on the floor in your doorway and make sure that its bubble is centered. Shim any hinged jambs until your level’s bubble has become visible on its own.
Make sure the door sill is flush with the drywall and apply a bead of caulk to prevent water damage. Finally, secure hinges and latch side of frame to studs for final assembly.
Finish the Job
Use a level to make sure the door frame is straight. If it is not, shim the trimmer stud with wooden shims until it is plumb before nail setting them to it.
Close the door and listen carefully as it latches shut; if it doesn’t, adjust the strike plate prong by slightly bending it toward its stop position.
Install a drip cap or Z-flashing above the new opening. Caulk around its frame, shimming where necessary to create an even gap with drywall and trim. Hide nail heads using putty as desired before painting or finishing as desired.