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9 Ways to Burglar-Proof Your Mail Slot

Written by | Updated July 10, 2020

Did you know that 81% of burglars enter through the first floor, and 34% enter through the front door?1 Picked locks may be the first vulnerability that comes to mind, but another major cause for concern is mail slots.

Burglars are known to slip wires and cords through vulnerable mail slots (or even their hand) to unlock front doors.1 Other potential breaches can occur with weak front doors and dark corners of your home’s exterior.

In order to keep thieves out, here are some tips about fortifying your mail slot and upgrading the rest of your home’s safety.

1. Replace your door

Whether you have a mail slot that you’d like to get rid of or an old front door that needs upgrading, you’ll want to make sure that’s the first line of defense against intruders. That’s why replacing it might be the best idea to prevent uninvited guests.

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When you’re shopping for a new door, you should go with one that doesn’t have a mail slot. It’s too easy for someone to stick their hand or a wire through the hole to open a lock. It’s also important to choose a door with shatter-proof glass so someone can’t smash their way into your home.

The team at SafeWise reviewed a number of security doors for this very purpose, and recommends a solid wood pre-hung door from The Home Depot as Best Overall thanks to its easy installation and high quality. For more security door options, read our review of the Best Front Doors for Improved Home Security.

When installing a new door, you can do it one of two ways: by calling a professional or doing it yourself. If you’d like to try your hand at installing a new door on your own, you can follow a step-by-step tutorial or watch a video if you’d rather to see it than read it.

2. Install a mail slot cover

Not in the budget to buy a new door package? Consider covering your mail slot to reduce your risk of tempting an intruder. You can go to your local hardware store and have a piece of thick metal cut and drill holes into your door to cover it or have someone cut a piece of wood to make a plug for your mail slot.

No matter the method, you should ensure that the inside and outside of your door’s mail slot are covered so thieves can’t just pry it off from the outside and work their way in. Make it weather-friendly and add to your home’s heating and cooling efficiency by adding a layer of insulation between the plug or covers. You can even get creative and find a decorative filigree to glue on top to hide the plug once you’re done.

3. Install a secure box

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Mail slots are pretty rudimentary. More secure options now exist that can protect your home and mail better. DuraBox is one brand that’s great. It is installed on the inside of your door so it can’t be tampered with and has a metal locked box that holds you mail. No intruder will be able to worm their way in by putting a wire or hand through the mail slot. This is completely enclosed, so it’ll be a dead end and a big safety upgrade to your front door.

4. Install a cage or sack

Similar to a security box, a cage or mail sack can also act as a barrier for burglars. Neither will be 100% impenetrable, but both can help keep the pets from chewing up your birthday cards at the very least.

5. Install a second deadbolt

Mail slots create a hole in your door that goes against the grain, weakening the door’s integrity. If someone tries to take advantage of your door’s weakness and kick it down, a second deadbolt can provide support and protection from them succeeding.

If you decide to install a second deadbolt, do three things: put it in a place that isn’t within arm’s reach of the mail slot, reinforce it so burglars can’t pop it out, and choose a model that has good customer reviews.  

Depending on what your door is made out of and the tools you have one hand, you might be able to install a second deadbolt yourself. You can find out how with convenient tutorials or by calling an expert.

There are a lot of deadbolts to choose from today—including locks with traditional keys to more sophisticated options with key pads. Pick a deadbolt with good consumer reviews and high safety standards.

6. Use an air vent diverter

Air vent diverters control the flow of air coming out of a vent, but they can also be cheap and effective ways to help prevent a burglar from violating your space. Place a plastic, shatterproof diverter at the top of your mail slot on the inside of your door. This stops thieves from reaching upwards with their hands or wire contraptions. You can find these on Amazon for less than $10.

7. Put on a mail slot hood

There are hoods specifically designed for mail slots. These can help provide the same or better protection as an air vent diverter, but are usually more expensive. That’s because mail slot hoods are often made of metal instead of plastic and provide a stronger material to deter thieves.

8. Use tape to cover your mail slot

This is a very quick fix and not something you should do long-term. If you don’t have time to fix your mail slot right away or burglar proof your front door, you can tape a piece of cardboard, metal, or plastic over the inside of the slot. Use something strong like Gorilla Tape and make sure to put out a mail box since the carrier won’t be able to fit anything through the slot. Using tape isn’t the sturdiest solution, but it’ll do in a pinch.

9. Reposition your mail slot

If you don’t want to give up having a mail slot on your door and don’t feel like installing a backup deadbolt, it’s essential you worry about where the slot is in relation to your lock. It should not be in line with the knob or door. Otherwise, you run the risk that a potential thief could use the mail slot to reach up and undo the lock. Place the slot low to the ground and in the middle of the door or to the side opposite the lock.

Bonus Security Tips

Reinforce your door

Keep people from kicking down your door by giving it stronger hinges. There are reinforcement products out there around the $75 range that can do this for you by strengthening your doorways and hinges. You can also purchase devices that go across the inside of your door to prevent people from busting through your door. Door clubs are a type of these protective devices that are cheap, easy to put up and take down, and can enhance your home’s security.

Make sure entryways are well lit and unobstructed

Good lighting is a sure way to keep trespassers away. If your front door has a bright light that you keep on at night, they won’t want to stand in the spotlight while trying to break in. The same goes for windows and other doors around your home.

Trim back bushes to remove potential hiding places for intruders. Add lighting around the perimeter of your home to illuminate dark corners where people might lurk. You can even get motion sensing lighting to give someone a jolt if they’re wandering onto your property and discover they’ve been seen.

Use a security system

One sure way to keep your home safe is with a home security system surrounding your door. Smart locks can help secure your door against threats. Cameras with motion sensors near your door might pick up when someone is attempting to stick their hands or objects through the mail slot or cracks of your door. A home security system with monitoring can help alert the authorities as soon as it picks up strange activity around your door.

You could consider an independent motion sensing alarm or a motion sensor light. The alarms can be noisy, but they can be programmed to sound when a larger object crosses its field of view, so it won’t have too many false alarms.

The exterior of your home is its first line of defense. It helps protect you and your family from the outside world and an unsecured mail slot could compromise that protection. Try some of these 12 solutions to fortify your home and keep burglars out.


1. Nick Gromicko, CMI, and Kenton Shepard, International Association of Certified Home Inspectors, “Burglar-Resistant Homes.” Accessed July 10, 2020.

Written by Katherine Torres

Katherine has had several years of experience developing and executing multichannel marketing campaigns, but actually started her career path in journalism. Though she switched gears, she continues to be driven by the need to deliver information that can be helpful for individuals. As an owner of two rescue dogs, she is most interested in technology and products that allow her to keep a close eye on her pets when she’s away. Learn more

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  • Cryptoyo

    Ricardo what about the millions of people who live in appartments with shared pigion hole boxes ? Not everyone lives in their own house with a drop the other side of the letter box!