How to Replace a Patio Door

A new, efficient patio door stops drafts, saves energy and eliminates leaks. Learn how to do your own sliding glass door replacement.

Next Project

A full day






If you've been putting up with a drafty patio door that sticks, fogs up or leaks during a heavy rain, it's time to consider a new, energy-efficient replacement. While a high-quality door isn't cheap, it'll cut down on drafts, require almost no maintenance, glide smoothly and latch securely. Best of all, you'll save $300-plus if you install a sliding glass door replacement yourself.

Tools Required

  • 4 ft. level
  • 4-in-1 screwdriver
  • Clamps
  • Drill/driver - cordless
  • Finish nail gun
  • Hammer
  • Miter saw
  • Pry bar
  • Reciprocating saw
  • Table saw
  • Tape measure
  • Utility knife

Materials Required

  • Flexible flashing
  • New sliding door
  • PVC cement
  • PVC sill pan
  • Silicone caulk
  • Wood shims

Project step-by-step (14)

Step 1

Measure the Opening Before You Buy

  • Pry the interior trim free.
  • Chip away drywall to expose framing.
  • Pull off the interior trim around the old door and measure the “rough opening” width (distance between studs) and height (floor to beam).
    • Pro tip: Make sure you measure to the framing right next to the old door jamb. You may have to cut away overhanging drywall to get at it.
  • To check the height, make sure you’re measuring to the subfloor.
    • That is, measure to the wood or concrete that the doorsill actually rests on and not a secondary layer of particleboard or plywood (underlayment).
  • Select a new sliding glass door that fits your rough opening.
    • Pro tip: Once you get your door home, you’ll save a lot of time if you finish any exposed wood surfaces on the door before beginning the installation.

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Step 2

Remove Old Sliding Glass Door From Frame

  • Latch the door, then unscrew and remove the inside head stop.
  • Unlatch the door, tip the top of the sliding panel inward and lift it free of the track.

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