Old patio doors reach a point where repairs stop making sense

Sliding patio doors are built to be repaired: rollers, tracks, locks and glass can all be replaced. A new door becomes the better project when the parts that cannot easily be replaced start to fail:

  • The frame and sill. Aluminum frames corrode, sills crack, and the seal between the frame and the wall gives out, so water gets in around the door instead of through it.
  • Protection. An older door without impact glass cannot be upgraded to impact performance by changing the glass alone.
  • Parts. When rollers, locks or panels for a door are discontinued, every repair becomes a workaround.
  • Several failures at once. Fogged glass, a pitted track and a failing lock on the same door add up.

If only one of these is wrong, a repair may still be the better choice. See roller repair, track repair and glass replacement, and the guide when to replace instead of repair.

Choosing the door starts with the opening, the rating and the approval

A visit to the opening comes before any product is chosen. It covers:

  • The opening. Width, height, how square and level it is, and what the frame will be anchored into, whether masonry, a wood buck or framing.
  • The configuration. Two panels with one sliding, three or four panels, or panels that slide into a wall pocket. Which side opens matters for furniture and foot traffic.
  • The performance. Every door has a design pressure rating, the wind pressure it is tested to resist. The Florida Building Code sets the wind loads for the site, and the door's rating has to meet them. Doors also carry water resistance and, for impact doors, impact ratings.
  • The approval. Florida law requires exterior doors to have product approval, statewide through Florida Product Approval or through local approval. In Miami-Dade and Broward, the High Velocity Hurricane Zone (HVHZ), the door needs approval valid for that zone: a Miami-Dade Notice of Acceptance or a Florida Product Approval valid for the HVHZ.
  • The glass. Impact laminated glass, insulated glass, or both, and tints or coatings that cut heat from the sun.

How a sliding patio door is installed, step by step

  1. Permit. Replacing an exterior door goes through a building permit. Miami-Dade publishes a permit process for window and door changeouts, and in Broward these permits use the county's uniform retrofit window and door schedule, with the product approvals attached. Many cities run their own building departments, so the permit is filed where the home is.
  2. Order the door. The door is built to the measured size. Lead times vary by product and supplier.
  3. Remove the old door. Panels come out first, then the frame. The opening is cleaned down to sound material, and any damage found behind the old frame is dealt with before the new frame goes in.
  4. Prepare the sill. The new sill is bedded in sealant on a level base, so water that reaches it drains outward and cannot pass under it.
  5. Set and anchor the frame. The frame is set plumb, level and square, and anchored with the anchor type, size and spacing the product approval specifies for that substrate. This step is what lets the door reach its rated performance.
  6. Install and adjust the panels. The panels go in, rollers are adjusted, and locks are aligned with their keepers.
  7. Seal and finish. The perimeter is sealed inside and out, and trim is fitted.
  8. Inspect. The building department inspects the installation against the permit and the approval.

For the homeowner side of the day, read how to prepare for installation day.

Florida patio doors are judged by wind, impact and water

In the HVHZ, exterior doors are tested for wind borne debris. The large missile test in TAS 201 fires a 9 pound piece of 2 by 4 lumber at the door, and the door then goes through cycles of wind pressure. A door that passes earns approval only in the configuration that was tested, which is why the installation instructions in the approval matter as much as the product.

Outside Miami-Dade and Broward, along the Gulf coast and the Treasure Coast, the code still sets wind loads and, in wind borne debris regions, requires protection for glazed openings. The approval route and the test standards differ, so the door chosen must fit the rules for that location.

Salt air, sand and humidity apply everywhere near the water. Frames with good corrosion resistance, stainless fasteners where the approval allows, and a sill that drains well last longer. Scheduling outside the August to October peak avoids leaving an opening exposed in a storm.

In condominiums, Florida law requires the board to adopt hurricane protection specifications for each building, and many buildings also require approval of exterior changes and set rules for contractors. Get the association's requirements in writing before ordering a door.

Questions to ask before you approve a new door

  • What is the product approval number, and is it valid for my county and, in Broward or Miami-Dade, for the HVHZ?
  • What design pressure does my opening need, and what is the door rated for?
  • Who pulls the permit and schedules the inspection?
  • How will the frame be anchored, and does that match the approval for my wall?
  • How is the sill sealed and drained?
  • What happens to the old door, and what is the total for the door, installation, permit and removal, confirmed in writing?

More detail is in what every Florida homeowner should know about patio door installation and hurricane impact sliding glass doors. Coverage is listed on the service areas page.