Install a patio door

Some packing blocks should be removed; others should be left in place until you're ready to install the molding. Refer to the manufacturer's instructions. The door shown is held in place with fasteners driven through the jamb. For a neat installation use a countersink bit to drill holes so the screw heads will be flush with the surface. Locate the holes according to the manufacturer's instructions. Working with at least one helper, lift the door onto the sill and tilt it in.

Press the unit into position against the siding. Have a helper hold the door in place while you make adjustments. Check the door frame for level, square, and plumb; continually recheck as you shim.

Tap in pairs of shims every 12 inches on the sides and the header, and every 8 inches on the floor. Tack partially drive nails or screws to temporarily hold the door in place. Reinstall the sliding panel and check for smooth operation. If your patio door has brick molding already attached, mark the siding for cutting now.

Back out the fasteners and remove the door. Just before you finally install the door, apply three beads of exterior caulk on the sill. Apply extra-thick caulk near shims to be sure the bottom of the threshold seals against the sill. Tilt the door back in place. Check that the threshold is straight and even.

Shim the sides and the header. If the door's jambs are the right width, the front of the jambs will be flush with the wall surface. Often, however, the jambs fall short of the wall surface. If so, make sure the distance between the jamb face and the wall surface is consistent all around, so you can fill in later with trim ripped to fit. If the jamb stands slightly proud of the wall surface, you will need to plane the jamb.

Install the sliding door and test for smooth operation. The gap between the door panel and the frame should be consistent at all points. Drive screws or nails to attach the threshold. If you see the threshold flex slightly when you slide the door, install additional shims as needed. Drive nails or screws to attach the side jambs. At the strike or strike box , install shims and drive a long screw to secure the strike. Install the latch, test, and adjust as needed.

Drive screws to install the head jamb. Slide the door and check the gap for consistency. You may need to back out some screws, adjust the shims, and redrive the screws. Use a handsaw to cut the shims flush with the framing or the wall surface. If the jamb does not come flush with the wall surface, cut the shims flush with the jamb edges. If the sill does not stick out as far as the brick molding, rip-cut a piece of siding or pressure-treated lumber to fit and nail or screw it in place.

You can install a kick board below the sill. Hold trim against the door for marking. Apply the trim using 10d galvanized casing nails when nailing into framing and 6d if nailing into the jamb. Use 10d galvanized casing nails for attaching integral brick molding. For flanged units, drive screws.

Rip-cut the jamb extender. To ease final installation, glue the extenders to the interior casing in advance. In this case the old casing could be reused because the replacement door was slightly smaller than the original door. Be sure to clamp each piece even with the casing.

With the rip-cut pieces of 1x glued to the casing, it can be trimmed to fit and reattached to the wall. The sliding panel can be adjusted up or down on one or both sides by turning an adjusting screw.

The screw may be on the bottom face of the panel or at either end. Check the screen panel for square. If it is out of square, stand it on one corner and pull down on the opposite corner. Install the sliding screen and adjust it so it slides easily. Apply a bead of exterior caulk all around the exterior trim.

Set any nails below the surface. Fill nail or screw holes with a dot of caulk. If you plan to keep the door open in the summer, see that the screen door seals tightly as well. Before cutting and removing any framing from the opening, the ceiling must be temporarily supported with posts and a beam to avoid structural damage to your house. The opening must then be framed correctly, with a large horizontal header spanning the length of the door overhead. For more about this, see Wall Framing for a Window.

Literature that comes with your door will tell you the exact size of the required opening. Make sure your opening is very close to perfectly square: Use a level to check the sides for plumb and the top and bottom for level. With a helper, hold the door up against the house, check it for level and plumb, and mark the siding for cutting. Cut the siding with a circular saw, taking care not to cut too deeply. Set the door in place again to make sure it will fit.

With existing construction, pry back the siding and slip in inch-wide pieces of roofing paper. Staple the paper to the framing so that all exposed wood is covered. Cut a piece of drip edge flashing to fit over the door. Slide it under the siding.

With new construction, just fasten the roofing paper and flashing to the studs and framing. With a helper, set the door in the opening. Have the helper hold the door in place from the outside while you work on the inside. Check all four sides for level or plumb. Gently tap in shims every 6 inches or so, and recheck the jamb for plumb and level.

Do not drive the shims too tightly or the jamb will bend.