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Patio Door Replacement and Installation

Decks, Patios, & Porches
By on Aug 25, 2020
Patio Door Replacement and Installation

If you have a deck or patio, chances are there’s more than an ordinary door connecting your outdoor space with the inside of your home. In contrast to the traditional porch, decks and patios are real living spaces that extend both the form and function of your home’s interior. And while we’d all like to keep the nasty weather outside where it belongs, we’d like to do so in a way that brings the spaces together as part of a whole. And the usual way is with a patio door.

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The classic patio door fits a double-wide opening and is made up of two aluminum-frame glass panels—one fixed and the other sliding. While the actual opening isn’t that much bigger than an ordinary door, the broad expanse of glass across the two panels creates a feeling of spaciousness and helps connect the indoors and outdoors in a visual way.

It’s not unusual, though, for older sliding patio doors to show their age. The rollers and tracks are subject to wear, making operation difficult. Handles may break and latches may become misaligned. Add to this the wide range of styles available to replace your old sliding unit, and the project begins to look attractive.

For our job, we installed a wooden model that’s vinyl-clad on the exterior with unfinished interior surfaces. The unit comes with double-pane insulated low-E glass panels. With a sliding screen and polished brass hardware, you’ll find this model selling in a range between about $1100 and $1300. Similar single-panel doors start at around $800, and large triple-door units go for over $2000.

Ordering Your Door

First, remove the interior trim and measure the width and height of the rough wall opening. At the floor, check to see if the old doorframe rests on the subfloor and abuts the edge of a finished floor, or instead sits on top of the finished floor. Make sure that the doorframe will sit high enough so the door will clear the floor adequately when it swings open. Also, bear in mind that an inswinging door hinged on the side of the frame (not on the center) will open beyond about 90° only if the inside of the frame is flush with the interior wall. For walls greater than 4-1/2 in. this will require exterior jamb and sill extensions. Be sure to discuss your particular requirements with your dealer if you’re at all uncertain. In our case, our rough opening was 72 in. wide x 82 in. high. The closest fit was a unit made for a 72 x 80-in. opening. When you order the door, also order the latchset, lock cylinder and any sliding screen or grille that you require.

Removing the Old Unit

Full-glass patio doors are heavy and it makes sense to disassemble the old unit and remove it in pieces. While sliding patio units vary in design and assembly, here’s the removal process we followed. Begin by removing the sliding door and fixed panel. To lift the sliding door out of its track, first unthread screws at the top and bottom rail and pull off the aluminum stile cover that prevents the panel from rising. Then, lift the door and swing the bottom in. Remove any screws securing the fixed panel to the track system and then remove the second frame in the same way.

With the glass out of the way, remove all screws that secure the aluminum tracks to the jambs and sill. Then, simply knock the tracks out from the wooden frame. Our underlying jamb, sill and exterior trim assembly was secured by nails driven through the trimwork into the wall framing. Use a cat’s-paw nail puller to remove these finishing nails, and slice through the exterior caulking with a utility knife.

Then carefully swing the frame out of the wall opening. To remove the old cap flashing, slide the blade of a reciprocating saw underneath to cut the nails. Then, pull the metal flashing out.


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Unless your rough opening matches the door maker’s specifications, you’ll need to shim the wall frame. It’s best to add equal shims on both sides of the opening so the new door will be centered and trim work will go more easily. First, check that the bottom of the opening is level. If necessary, cut wooden shims to level this surface and bring it to the required height in relation to the finished floor. Then, shim out each side and the top of the opening to meet the new door’s requirements and check that these surfaces are plumb, level and square.

With the opening ready, lay the new door on its back on two 2 x 4s and install the plastic top and side flanges by tapping them into the grooves in the doorframe. Then, use a small pry bar and screwdriver to remove the screw covers at the sides and top of the casing. With the screw covers off, the screwholes for securing the assembly to the house wall will be accessible. Finally, apply a few beads of silicone caulk to the base of the rough opening.


Have at least one helper on hand to help you lift the door into the opening. If the opening is more than a few inches above the level of the patio or deck, set up a temporary ramp with 2 x 4s and blocking on which to slide the patio door along. Slide the bottom of the doorframe into the rough opening and then swing the top into place. Press the door in until the flanges meet the wall sheathing. Check that the unit is plumb on all vertical surfaces, and level. Then, locate the prebored screwholes in the sides and partially drive the screws to temporarily hold the door in place.

Have some tapered shims or wood shingles on hand to shim the door at each screw location. Insert the butt end of a shim into the gap between the rough opening and doorframe just above a screw. Then, trim the narrow end of a second shim so when it’s slid against the first it fits tightly between the doorframe and the rough opening. Be careful not to force the shims and bend the frame. On the other hand, once the screws are in place they will tend to pull the frame a little farther toward the wall. After shimming at each screw location and making final checks for level and plumb, drive the screws into the wall framing. Then add any required screws through the latch hardware or hinges. Remove any spacer clips installed around the door for shipping.

Latchset and Hinges

Install the latchset according to the instructions supplied with the assembly. Next, check that the door is hung correctly. When open, the door should remain motionless. If it swings either way on its own, and the frame appears level and plumb, adjust the door tilt at the hinges. The adjustable hinges allow you to alter the gap between the door and frame at the top and bottom. To adjust the tilt, first loosen the two position-fixing screws at the top and bottom hinges. Then turn the horizontal adjusting screw in the center of each hinge clockwise to decrease the gap at the hinge frame member, or counterclockwise to increase it. Make opposite adjustments to the top and bottom hinges to tilt the door one way or the other. Tighten the position-fixing screws and check that the door remains still when open.


With the new patio door in place, fill the gaps around the perimeter with fiberglass insulation. If your door is slightly smaller than the rough opening, add drywall to fill the space and tape the joints. Our door required interior extension jambs to bring the frame flush with the wall surface. Make extension jambs by routing a rabbet along the edge of 3/4-in. pine stock to produce a lip that fits in the center groove of the doorcasing. You can also buy extension jambs from your supplier.

Rip the stock slightly wider than necessary and cut the lengths to fit the sides and top of the doorframe. Hold each piece in place and scribe the exact width to match the plane of the wall. Now, trim each piece to the line and secure it with screws. If your jamb extensions are deep, counterbore screwholes so the screws reach the jambs.

With the jambs finished, cut and install new interior trim. Drive finishing nails into the extension jambs and wall framing, set the nails and fill the holes.

On the outside, we were left with a gap between the new exterior vinyl-clad jambs and our clapboard siding. After installing new cap flashing, rip 1 x 4 pine to fit these openings and secure the new trim with finishing nails. Paint all bare wood with a quality latex primer, follow with the finish coats of your choice and caulk around the exterior trim. Finally, reinstall the snap-on screw covers around the sides and top.

Copyright © Popular Mechanics 2001. Reprinted by permission

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