Patio door replacement takes out a worn sliding glass door or set of French doors, frame and all, and installs a new, sealed unit in the opening. We do patio door replacement in St. Joseph for back doors onto decks, patios and sunrooms. You get a door that slides or swings easily, locks securely and keeps the weather out, set on a sill we've checked for rot first.
Sliding glass doors and French doors
A sliding patio door has one fixed panel and one that rolls along a track. It takes no floor space to open, which is why it's the most common back door on houses from the 1960s on. Hinged French patio doors swing open, either one active door beside a fixed one or two that both open. They give a wider opening and suit older houses, but need room to swing inside or out.
Either way, the new unit comes as a complete door: frame, sill, panels and hardware. Patio door glass has to be tempered safety glass, and the usual choices beyond that are low-E coatings, grilles, and blinds sealed between the panes.
What patio door replacement involves
- Measuring and checking. We measure the opening and check the floor under the sill. Water that has gotten under an old sill for years often softens the subfloor, and that has to be fixed before a new door goes on it.
- Removal. The panels come out first, then the frame. Interior trim is removed carefully so it can go back or be replaced.
- Setting the new door. A sill pan or flashing goes down first so water can't get under the door again. The frame is set level and square and fastened, and the gaps are insulated.
- Finishing. Trim inside, sealing outside, the handle, lock and screen adjusted, and the door run open and shut until it moves easily.
When a patio door should be replaced
Replacement makes sense when the door itself is the problem: the frame is bent or warped, the sill is rotted, the glass has fogged between the panes, cold air comes in around a door that's already been adjusted, or water shows up on the floor after a hard rain. It also makes sense when you want to change styles, from a slider to French doors or the other way around.
If the door is in good shape and only drags, a new set of rollers or a cleaned track may be all it needs. That's a repair job, not what we do, and we'll tell you if that's where you stand.
Why patio doors wear out
A patio door is opened more than any window in the house, and its sill sits right where rain, snow and deck splash land. Rollers flatten, tracks wear and collect grit, weatherstripping compresses, and the seal around the insulated glass eventually lets go. As a house settles, the opening can shift just enough that the door never closes quite right again.
What affects the cost of a new patio door
- Style: sliding, single French with a fixed panel, or double French doors.
- Width and height, and whether the opening has to change size.
- Frame material: vinyl, fiberglass, wood or wood clad in aluminum.
- Glass options, grilles and built-in blinds.
- Repairs to the subfloor or framing found under the old sill.
- Interior and exterior trim.
Angi reports most patio door replacements running from about $1,550 to $6,250 nationally (October 2026). Your written estimate is the number that counts; the cost page explains how we price it. Windows near the door, or a bay window in the same room, can be measured on the same visit, along with any vinyl replacement windows you're considering.
Patio door questions
Which is cheaper, sliding patio doors or French doors?
A sliding door is usually the less expensive of the two at the same width. It has one moving panel and simpler hardware, while hinged French doors need more hardware, a sturdier frame and room to swing. Frame material and glass matter as much as the style, so compare quotes for the same width and glass.
How long should it take to replace a patio door?
A standard patio door in a sound opening is usually replaced in a day, start to cleanup. A rotted subfloor under the sill, a change in opening size, or a switch from a slider to French doors adds time. The door itself is made to order, so expect a wait before install day.
What is the life expectancy of a patio door?
It depends on the frame material, how much weather the door takes and how hard it is used. Rollers and weatherstripping wear out first and can be serviced. When the frame warps, the sill rots or the sealed glass fogs, the door has reached the point where replacement makes more sense.
Do I need a permit to replace a patio door?
Check before work starts. The city’s Building Development Services handles permits, and we confirm with them what your job needs before we begin. If your house is in Museum Hill or Hall Street and the door can be seen from a street or other public place, the Landmark Commission also has to approve it.
Price a new patio door
We'll measure, check the sill and give you sliding and French options in writing.
Request an estimate