How to Install Window Security Bars

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Security bars don't have to make your home look like a prison.
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An unfortunate reality of urban living is the ever-present possibility of intruders breaking into your home. They may be burglars or worse, and they're more prevalent in some urban areas than others. Detroit topped Forbes list of the most dangerous cities in the U.S. again in 2017, and Oakland, California, and St. Louis, Missouri, weren't far behind. If you live in one of the cities on the Forbes list, or even if you don't, you are probably familiar with window security bars. They aren't the only window-related security option for your home, and they aren't necessarily the best, but they are generally easy enough to install. In fact, you should be able to do the job yourself.


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Installation methods vary according to the product, but there are two basic strategies. The first and least secure is to mount the bars to the outside of the window frame using security screws that can't be easily removed. The second, better option is to mount the bars to the studs framing the window from inside the house. This means a potential burglar might be able to break the window glass, but without special cutting tools, they probably won't get much farther.

Make sure that the model you choose conforms to the local egress codes. Most building departments have them to ensure that building occupants can escape in the event of an emergency, such as a fire that might block the main entrances.

How to Buy Burglar Bars

Security bars are also known as burglar bars, and they come in a wide variety of styles that range from highly decorative wrought iron barriers to purely functional wire mesh. When choosing a style, you have to balance your security needs with aesthetics. Low windows and basement windows, especially those facing a fence or neighboring wall, are candidates for the most secure and least attractive bars, while front-facing windows call for more decorative ones.

Before shopping, you need the exact measurements of the window frames on which you plan to install them. As a rule, exterior-mount bars should be a few inches longer and wider than the window, and interior-mount bars should fit snugly inside the frame with perhaps a 1/2-inch clearance. Measure the width and height of the window from inside, stretching a tape measure between the side frames and from the top frame to the sill. This is the measurement you need when shopping for bars. If your window isn't a standard size, you may have to have the bars custom-built.

Mounting Exterior Security Bars

Depending on the siding material, mounting exteriors on a single window is a job that an average homeowner can complete in an hour or two. The job may take a little longer if the siding is brick or concrete. You basically position the bars in the position you want, level them vertically and horizontally with a spirit level and then mark the positions of the holes on the mounting brackets. Drill a pilot hole on each mark; then reposition the bars and drive a nonreversing security screw into each hole to secure the bars in place.


When mounting on brick, stone or masonry, you have to drill a hole large enough for a conical screw anchor, using a masonry bit. This may take some time, and it's helpful to keep a bowl of water handy so you can periodically dip the bit to prevent it from overheating. The hole should be 1/2 to 1 inch deeper than the length of the screw. Once you've drilled it, tap in the anchor, and when all four anchors are in place, you can mount the bars.

Exterior bars usually do not allow egress, so check with your local code requirements before installing them. The codes usually allow them on some windows as long as you have sufficient egress through other windows in the house.

Mounting Interior Security Bars

Interior window bars often come with quick-release mechanisms that allow you to open the grille like a door or remove it from the frame altogether. The ones that open usually satisfy ADA egress requirements by providing a 24-inch high, 20-inch wide escape opening. Check with the building department before installing bars that have a locking mechanism that requires a key. It may not satisfy egress requirements because the key can get lost.

The bars must fit inside the window frame and typically come with an installation kit that includes rails and screws. The installation instructions will outline the exact procedure for the product you have. In general, you screw one of the rails to the window frame, slide the other rail onto the bar set, slide the bars into the rail attached to the window frame and finish up by securing the other rail to the frame.

When mounting the rails, be sure to use a level to plumb them, mark the positions of the holes and drill pilot holes in the window frame with an appropriately sized bit — usually 1/4- or 5/16- inch. The screws that come with the kit are long enough to bite deeply into the studs behind the window frame, so once the bar set is properly mounted to the rails, it's there to stay.