Patio door installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What patio door installation is

Patio door installation replaces a patio door by removing the old unit, repairing the framing and sill, and setting a new door level, sealed and flashed. The lock and glide are checked before the work is finished. People call when a patio door is drafty, leaks at the sill, sticks, or is cracked or fogged.

Signs you need it

  • Drafts or water at the sill, the threshold or the edges of the glass panels
  • A patio door that sticks, will not lock, or sags at the handle side
  • Cracked or fogged glass, or a frame that is warped or failing at the corners
  • Rot or soft wood at the sill, or stains on the floor beside the door
  • An old patio door that is hard to open and close, or that uses single-pane glass which feels cold to the touch

What the pro does

  • Remove the old patio door, then check the rough opening, the sill and the jambs for rot, water damage and level
  • Repair the framing and the sill, then set a sill pan and flashing that carry any water out and away from the house
  • Set the new door unit level, plumb and square in the opening, and shim it so the panels run smoothly and the frame does not bow
  • Fasten the frame through the shims, then install the lock, the handle and the weatherstripping along the meeting rail
  • Seal the exterior joints and the threshold, check the glide and the lock, and fit the interior and exterior trim

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Door size, number of panels, and the glass package, including insulated and laminated glass
  • Frame material, such as vinyl, wood, fiberglass or aluminum, each with different parts and labor
  • Sill and framing repair needed, including rot found when the old door comes out
  • Threshold type, including low-threshold or accessible thresholds that change the flashing
  • Lock and hardware choices, including multi-point locks and smart locks
  • Exterior finish and interior trim needed to match the house
  • Permit and inspection requirements for changes to the opening

What a written quote should spell out

  • Door type, panel count, size and glass package named, with the manufacturer
  • Frame material and color or finish, with the sill and threshold type
  • Sill pan, flashing and framing repair listed as their own lines, with photos
  • Lock and handle type, and the weatherstripping along the meeting rail and the bottom
  • Interior and exterior trim included, with the profile and finish named
  • Removal and disposal of the old door, and cleanup of the glass and debris

Questions to ask before you hire

  • How is the sill flashed, and how does water drain out from under the door?
  • Will you check the framing and sill for rot before the new door goes in?
  • What glass package is included, and does it have the coatings I asked for?
  • How do you set the threshold so it seals without becoming a trip hazard?
  • What lock and hardware do you install, and does the multi-point lock line up?
  • What warranty covers the frame, the glass seal and the install?
  • Can you show me a recent install with the same door type and threshold?

Red flags

  • A patio door set on a sill with rot and no repair in the quote
  • No sill pan or flashing listed, with sealant as the only protection at the bottom
  • Shims left out at the frame, so the panels bind or the glass cracks
  • A quote that does not name the glass package or the coatings
  • Door panels ordered before the opening has been measured on site

What you can do yourself

You can safely clean the track, lubricate the rollers as the maker directs, and check the sill and outside joints from the ground for cracks and water staining. Removing a patio door, cutting into the wall and flashing the sill are heavy, structural tasks that affect water and the house, so leave them to a pro. Call a pro for a new patio door unit, rot at the sill, or a door that lets water in at the bottom.

Licenses and permits

Patio door installation is commonly done by licensed window or door contractors, and rules vary by place. Check with your state and local licensing agency, and the local building office if the opening, sill, framing or structure changes.

Patio door installation questions

Should I choose vinyl, wood or fiberglass for a patio door?

Each frame material handles weather, maintenance and look differently. Vinyl needs little upkeep, wood needs finishing, and fiberglass is strong and stable. A pro can show you samples and explain the differences for your exposure.

Why does my patio door fog between the glass?

The insulated glass seal has failed and moisture is inside the unit. The glass unit must be replaced, because cleaning will not clear it.

Can I keep the old frame and only replace the door panels?

Only if the frame, the sill and the track are sound and square. Otherwise the new panels may bind or leak. A pro should check the frame before you decide.

How do I stop a low threshold from leaking?

The sill pan and flashing must carry water out, and the threshold must be set to seal against the panels. A pro should check the threshold height and the flashing before finishing the install.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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