Installing Doors and Windows

A pre-hung door or window will make this project much simpler. These come with the door or window, the jamb and the trim molding already assembled. All that is required is to open the wall, adjust the framing to the proper size and slide the new unit into place.

To start the installation first determine the size of the opening for the new door or window. The required space for pre-hung units will be included in the door packaging. See Remodeling a Wall and Framing Doors and Windows for help with the wall demo and framing. With the new framing done repair any wall damage around the new opening before installing the new door or window. See Drywall and Plaster for help.

Install the New Pre-hung Unit

Remove the trim molding from both sides of a pre-hung unit. Don't remove any nails, screws or other device holding the door or window stationary within the jamb.

Move the unit into place. When installing doors and large windows, a helper may be needed to assist. Set doors into the framed opening so that the jamb is flush with the surrounding wall plaster on the hinge side of the door. Be sure the trim molding will lay flat against the wall and jamb when installed. If after the door is plumb and square the jamb is not flush with the wall surface on other side of the door, a jamb extension can be added to build it out flush with the wall.

Install windows from the outside of the house. Set the window jamb flush with the exterior wall and add a jamb extension on the inside if necessary.

Slide pairs of shims between the jamb and jack studs to hold the unit in place. Drive the shims from each sides of the door or window to form pairs around the frame.

For doors, place the shims near the hinges and every 12 inches or so along the header. Space shim pairs about every 12 inches around a window jamb, along the header and sill.

Adjust the unit until it is plumb and flush. Hold a level against the jamb and drive the shims into the gap between framing and jamb until the centered bubble indicates the unit is plumb. Avoid causing the jamb to bow by forcing the shims too far into the gap. They should be snug but not jammed in the space.

Adjust the shims along the header until the space between door and jamb (the reveal) is consistent.

Drive 12d finishing nails thru the jamb, the shims and into the wall framing to secure the unit in place. Space nails at 12 inch intervals around the jamb. When the jamb is secure use a handsaw to cut the shims off flush with the wall plaster. Add a jamb extension if necessary to build out the jamb and re-attach the molding that was removed from the pre-hung unit earlier. Remove any stabilizer holding the door or window sash in place and make sure they function properly.