How to replace a sliding glass door
Remove the old unit, clean up and inspect the rough opening to prepare for installation of the new door. You will need a helper to assist you in removing the old door and lifting the new one in place.
Sliding glass doors are a popular choice in homes with backyard decks or patios – they allow plenty of natural light and views while connecting the outdoor space to the interior.
But once they begin to show their age, sliders may not operate smoothly or efficiently.
Rollers and tracks wear out after heavy use, handles become misaligned and broken, and the doors no longer seal out the weather. While those problems can be fixed fairly easily, with the advancements in sliding glass doors, homeowners often choose to upgrade.
New doors have become more affordable and efficient, making the choice to replace a sliding glass door a cost-effective option, and contractors can realize a healthy profit from this simple job.
Waterproof the bottom of the opening by applying either a flexible waterproofing membrane or a rigid sill pan, as seen in this photo. Be sure to extend the membrane or pan up the sides of the opening by about 6 inches.
Remove the old unit
To replace a sliding glass door, begin by removing the sliding door and fixed panel. Many fixed panels are held in place by screws and stile panels, while some vinyl sliding glass doors have integral fixed panels that cannot be removed.
The point is to remove as much weight from the unit as possible before removing the unit itself from the opening.
Remove any interior, exterior trim elements or J-channel next. Remove all screws that secure the aluminum tracks to the jambs and sill. Some units may not have any screws to remove.
Use a cat’s paw to remove any nails that secure the doorframe to the framing of the rough opening either through the trim or through the jambs or sills. Remove screws with a drill/driver.
Slice through any caulking that has been applied to seal the trim and siding or the doorframe and interior finishes. Carefully swing the unit out of the wall opening.
Tip the new unit into the rough opening by placing the bottom in first. Lift and place the bottom of the unit in place – do not slide it in – to avoid smearing the additional beads of silicone applied on top of the sill pan or membrane.
Prep the opening and new door
If the rough opening doesn’t match the new door’s specifications, you’ll have to shim the opening. Begin with the bottom of the opening to make sure it is level and the installed door will match the finished floor’s elevation properly.
Shim the rest of the opening if necessary and ensure everything is plumb, level and square. If possible, do a dry fit with the new sliding glass door to ensure everything fits easily and properly.
Apply a waterproofing membrane or sill pan to the bottom of the rough opening in the same way you would for a window installation, extending the membrane at least 6 inches up each side of the rough opening. Apply two or three heavy beads of silicone caulk across the length of the membrane, paying special attention to the corners and making sure that silicone will not ooze out onto finish materials such as flooring or wall surfaces.
Place shims where necessary between the rough opening and the new unit’s frame. Ensure the entire unit is plumb, level and square before securely attaching the nailing flange or jamb screws.
Set the new sliding glass door
Set the bottom of the new unit in place, being careful not to slide it and smear the silicone. Tip the rest of the unit into place until the flanges are tight to the exterior wall. If your unit has no flanges, use temporary blocks to hold the unit in place so that its frame fits flush with the exterior wall sheathing.
Check the unit for plumb/level/square and partially drive screws into the pre-drilled holes in the door jamb to hold it in place. For vinyl units with no holes in the jambs, tack a couple of nails into each corner of the nailing flange.
Shim the door if necessary. Place tapered shims at each screw location and drive screws through them, or for vinyl units simply place a few shims to keep the frame straight and secure as you nail around the flange. Make sure you keep checking for plumb/level/square, as screws can often pull the jambs out of alignment.
Drive jamb screws through the pre-drilled holes and into the shims and wall framing. Be careful not to overdrive these screws, as you can dimple or otherwise distort the door’s frame.
Trim all shims. For units with an integral nailing flange, apply flashing material over the flange and wall sheathing. Start with the sides first, then overlap those with a flashing element along the top and apply a drip cap on top of the unit. Again, this is just like flashing a window.
Add any screws required through the latch hardware or hinges and remove any spacer clips installed around the door for shipping purposes. Install latch sets and any other hardware or accessories.
Install exterior trim, applying caulk between the new door unit and trim to provide protection from weather and a finished appearance.
Insert insulation into the gap between the door frame and the rough opening from the interior. Expanding foam insulation made for windows and doors is the best option. Install interior trim and the sliding glass door installation is done.
