Replacing your old front door with a pre-hung door is one of the quickest and least expensive ways to keep a homeowner's cost down while providing the desired look.
Installing a traditional door frame and an exterior door can be difficult since the frame needs to be measured, hinged and squared. If the builder doesn't have the right framing knowledge or the proper tools, this can be tedious and frustrating.
Installation of a pre-hung door is easier since the door is already attached to the door frame. It requires fewer tools and there's no need to chisel and set the hinge since it is already pre-installed with the door. This cost-effective option also gives the homeowner many choices, from wood to fiberglass, and each style can be either painted or stained.
Here's how to do it:
- Inspect the studs for water and insect damage, and make sure the rough door opening is at least 1" wider and 1/2" higher than the outside dimensions of the new door frame unit. Pre-hung doors come in a standard door jamb of 4" to 9/16" or 6" to 9/16".
- Place the door unit in the rough door opening bottom end first and visually center it.
- Wedge some shims between the side jambs and the frame until the frame is level and plumb with the already flashed door sill.
- If the exterior siding needs to be cut because it is overlapping the brick molding, a.k.a. exterior casing, trace the outline of the molding onto the siding. Use a circular saw to cut through the marked siding, and trim the siding at the corners with a sharp chisel.
- Apply a generous amount of silicone or caulk to the jambs and rough opening.
- Slide the door unit into place again and center it, then temporarily secure the brick molding with finishing nails.
- From the inside, insert pairs of shims in the gap between the door jambs and the studs where the lockset and hinges are located.
- Insert additional pairs of shims every 12" along the side and header jambs. Don't force the shims into place since they may cause the frame to bow. Use a level to make sure the door is still plumb.
- Maintain a 1/8" space between the door edge and the jamb on the lock side on the door and 1/16" on the hinge side.
- Fasten the door frame to the rough opening where the hinge is.
- Remove one of the hinge screws and use a longer screw (usually provided with the door) to screw the door at the hinge, through the shims and framing. Repeat on the other side and screw in where the weather stripping is.
- Remove the weather stripping and screw it on the frame at the locations where you have shimmied the door. Replace the weather stripping.