How Do You Make an Existing Door Secure Against Intruders?

Although locks are likely the most widely acknowledged security feature, the other hardware on your door can ensure that the lock works most effectively. The weakest part of the door’s system is what makes it most vulnerable. You can adjust the following aspects of your door that work together to provide you the most security.


A door’s weakest part is often its frame. To strengthen an existing frame, you can install 3-inch to 4- inch screws through the doorstop strip and frame. Ensure that the screws go through solid wood; add shims or blocks between the studs and jambs if necessary. This solid surrounding for the door prevents an intruder from wedging something between the door and frame, causing the frame to bow, according to Shorewood on the Sound.

You can also add rigidity to your existing door frame with a piece of 1-inch flat steel that’s as tall as the door frame. Use 3-inch to 4-inch screws to attach the steel reinforcement every 12 inches.

Reinforcement Kits

Companies provide several kinds of reinforcement kits that you can install. One type is horizontal or vertical locking bars, also called three-point lock systems, that can lock into the header and/or studs around your door. The bar braces across the door, resisting attempts to kick or otherwise force the door inward. Each end of the bar locks into another piece, providing the door with two additional locking points.

Another kind of reinforcement kit comes with a jamb shield, hinge shields, door shields and long screws. This type of kit is ideal if your door fits fairly loosely (at least 1/8 inch gap) in its jamb. The hinge shields are metal plates that reinforce the hinge’s attachment to the door jamb. The jamb shield reinforces the jamb above and below where the latch and dead bolt go into the jamb. The shields distribute a force more widely, preventing focused damage to either the hinges or the dead bolt or latch.

Dead Bolts

Dead bolts should be solid metal, and all screws should be accessible only from inside. Dead bolts should extend at least one inch into the wall (this part of the bolt is called the “throw”). Ensure that when the lock is fully extended, part of the bold remains in the lock.

Installing a double-cylinder dead bolt means that each side requires a key. Single cylinder locks require a key from the outside and have a lever on the inside. If you’re home, you can leave the key on the interior side so that you can easily vacate the premises in case of emergency, including fire. If you leave your house, take the interior key with you. An intruder who might break in through a window faces a door locked from the inside, which can make it difficult to remove large items.

You can install additional dead bolts at the top or bottom of your door. Although this method is more cumbersome for daily use, it provides protection similar to the locking bars mentioned above, assuming that the door material is sound.


Exterior doors should open inward, and the hinges should be on the inside to prevent an intruder from removing the hinge pins from outside and then simply removing the door. If it’s impossible to switch a door to open inward (for example, in an apartment building), you can install door hinges with non-removable pins or modify the pins to make them non-removable. You can drill and tap a hole through the hinge into the pin. Install a machine screw and then grind off the screw head so that it can’t be removed.

Strike Plate

A metal strike plate can be installed where the door latch and dead bolt meet the jamb. The strike plate prevents a crowbar from being wedged between the frame and the door, crushing the frame and allowing entry. It’s important to use very long screws to stabilize the strike plate. 3-inch or 4-inch screws go all the way through the frame into the studs or header, providing additional strength.


If installing any of these items results in accessible screw heads, you can use a small drill bit to obscure the slots that a screwdriver might fit in to.

Whether you choose to focus on your door’s frame or hardware, including dead bolts, hinges, and strike plates, or add a reinforcement kit, you have lots of options. Depending on your budget and skill, you can choose how best to make an existing door secure from intruders.

Related Resource: Low-E Glass