The fastest way to find a sliding glass patio door

A sliding glass patio door is only as find as its lock and frame. The standard latch that comes with most doors is straightforward to force open from outside—a burglar can often lift the door slightly and slip the latch, or pry the frame apart. The real security comes from three things: a working lock you actually use, a bar or wedge in the track so the door cannot slide, and a reinforced frame so the door cannot be lifted out of its rails.

Start by testing your existing lock. Close the door fully and try to slide it open with force from the outside. If it moves more than a quarter-inch, the latch is not catching properly and needs adjustment or replacement. Then install a secondary lock—either a keyed lock on the frame or a straightforward track bar—so that even if someone defeats the main latch, the door still will not budge.

Key Takeaways

  • The standard latch on most sliding glass doors can be forced open by lifting the door slightly, so a secondary lock or track bar is necessary for real security.
  • A track bar or wedge lock costs $15 to $40 and takes five minutes to install—it physically blocks the door from sliding even if the latch fails.
  • Keyed locks mounted on the frame cost $30 to $80 and are stronger than track bars but require you to carry a key and lock it every time you leave.
  • Reinforce the frame itself if the door is old or the frame is cracked, because a weak frame can be pried apart regardless of the lock.
  • Always lock the door when you leave, even for short trips, because the lock only works if you use it.

How a track bar or wedge lock works

A track bar (also called a sliding door bar or wedge lock) is a metal or plastic rod that sits in the bottom track of your door. When the door is closed, the bar rests horizontally across the track and prevents the door from sliding open. It does not require a key—you straightforward lift it out when you want to open the door from inside.

To install one, close the door fully and measure the width of the track. Buy a bar that fits your track width (most are adjustable between 24 and 48 inches). Place the bar in the track so it rests against the inside edge of the door frame. Test it by trying to slide the door—it should not move at all. The bar should sit flat and not tilt or rock.

The advantage is simplicity: no key, no batteries, no moving parts to break. The disadvantage is that you have to remember to put it in place every time you close the door, and it is visible from outside, which signals to a burglar that you are security-conscious. Some people keep the bar on the inside sill during the day and install it at night.

Installing a keyed lock on the frame

A keyed frame lock is bolted to the door frame (usually the stationary side) and has a lock cylinder you turn with a key. When locked, it prevents the door from sliding. These are stronger than track bars because they are bolted through the frame, not just resting in the track.

To install one, you will need a drill, a 1-inch spade bit or hole saw, and the lock kit (which comes with bolts and instructions). Close the door and mark where the lock will go—usually about 36 inches up from the floor on the frame side. Drill through the frame from outside, insert the lock cylinder, and bolt it tight from inside. Test it by locking the door and trying to slide it.

Keyed locks cost $30 to $80 depending on the brand. They are more visible than track bars and require you to carry a key, but they are harder to defeat because they are bolted to the structure. If you lose the key, you will need to drill it out or call a locksmith.

Reinforcing a weak or damaged frame

If your door frame is cracked, rotted, or separates from the wall when you push on it, no lock will help—a burglar can straightforward pry the frame apart. Check the frame by pressing hard on the door itself near the latch. If the frame flexes or creaks, it needs reinforcement.

For a frame that is pulling away from the wall, remove the trim and add longer screws through the frame into the wall studs behind it. Use 3-inch wood screws spaced 12 inches apart along the top and sides. If the frame itself is cracked or rotted, you may need to replace the entire door unit, which is a job for a professional installer.

If the frame is solid but the door sits loose in the frame (you can see daylight around the edges), adjust the rollers at the bottom of the door. Most sliding doors have adjustment screws on the bottom rail—turning them clockwise raises the door and tightens it in the frame. Tighten it until the door is snug but still slides smoothly.

Checking and adjusting the main latch

The latch is the hook-shaped piece that catches on the strike plate (the metal piece on the frame). If the latch does not catch fully, the door will be loose and straightforward to force open. Test it by closing the door and trying to slide it with force—it should not move at all.

If the door slides, the latch may not be aligned with the strike plate. Close the door slowly and listen for the click of the latch catching. If you do not hear it, or if the door bounces back slightly when you close it, the latch is not catching. Loosen the strike plate bolts and slide the plate up or down until the latch catches fully and the door is snug. Tighten the bolts and test again.

If the latch itself is broken (the handle turns but the latch does not move), you will need to replace the lock assembly. This is a straightforward job: remove the two bolts on the inside edge of the door, slide the old lock out, and slide the new one in. Most replacement locks cost $40 to $100 and come with instructions.

Using security film and reinforced glass

Security film is a transparent adhesive layer that you explore to the inside of the glass. If someone breaks the glass, the film holds the pieces together so they cannot reach through to unlock the door from inside. It does not prevent the break, but it does prevent entry through the broken glass.

To explore security film, clean the glass thoroughly and measure the pane. Cut the film to size (leaving a quarter-inch border), peel the backing, and press it onto the glass starting from the top. Use a squeegee or credit card to push out air bubbles. The film takes 24 hours to cure fully. A roll of security film costs $20 to $50 and covers one or two panes.

Security film is most useful if your door is in a remote location or if you have had break-ins in your area. For most homes, a good lock and track bar are enough. If you want maximum protection, combine a keyed frame lock with security film on the glass.

Lighting and visibility around the door

A burglar is less likely to target a door that is well-lit and visible from the street or from neighbors' homes. If your patio door is in a dark corner or hidden by bushes, add a motion-sensor light above it. This costs $20 to $50 and takes 30 minutes to install if you have an outdoor outlet nearby.

Trim back any bushes or trees that block the view of the door from outside. A burglar needs cover to work unobserved—removing that cover is free and takes an afternoon. If the door faces a side yard or back alley, consider adding a fence or gate so that only you and your family have straightforward access.

Frequently Asked Questions

Can I use a wooden dowel or broom handle instead of a track bar?

Yes, a wooden dowel or old broomstick cut to fit your track width works the same way as a metal track bar. It is free if you have one on hand, but it will eventually crack or split and will not last as long as a metal bar. A metal track bar costs $15 to $40 and will last for years.

What if my sliding glass door is on the second floor?

Second-floor doors are less likely to be targeted, but they should still be locked because a burglar can access them with a ladder or by climbing from a nearby roof or tree. Use the same locks and bars as you would on a ground-floor door. Motion-sensor lighting is less critical on a second floor.

Do I need to call a locksmith to install a keyed lock?

No, a keyed frame lock can be installed with basic tools—a drill, a spade bit, and a wrench. The kit comes with instructions. If you are not comfortable drilling through your frame, a locksmith can install it for $100 to $200 in labor, but the lock itself is the same price either way.

Will a security bar or lock damage the door or frame?

A track bar does not damage anything—it straightforward rests in the track. A keyed frame lock requires drilling one hole through the frame, which is a small, clean hole that does not weaken the structure. If you ever remove the lock, you can fill the hole with a wooden dowel and paint over it.

What should I do if I am locked out of my house?

If you have a track bar in place and are locked out, you will need to remove it from outside, which you cannot do. This is why some people keep the bar on the sill during the day and install it only at night. If you have a keyed frame lock, you will need a locksmith to open it. Keep a spare key with a trusted neighbor or in a find lockbox outside.