Measure the rough opening and confirm the new patio door size fits
Remove the old door, trim, casing, and any fasteners
Inspect the opening for rot, damage, or uneven framing
Repair or replace damaged framing members
Check that the sill is level and the opening is plumb and square
Apply flashing tape or waterproof membrane to the sill and jambs
Dry-fit the new patio door in the opening
Apply a continuous bead of exterior-grade sealant to the sill
Set the door frame into the opening
Shim the frame until it is level, plumb, and square
Fasten the frame through the manufacturer’s recommended points
Recheck alignment as you tighten the fasteners
Install insulation around the frame without overpacking
Apply flashing tape around the exterior perimeter
Install exterior trim or casing
Seal all exterior joints with high-quality exterior caulk
Install the door panels, rollers, handles, and lockset
Adjust rollers and latches for smooth operation
Test the door for proper opening, closing, and locking
Install interior trim and caulk interior gaps
Clean the glass and remove all debris from the work area