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How to Build a Fireproof Safe | Constructing vs Re-Purposing

Storing valuables in your home can be stressful. You may worry that your belongings will be stolen, but even if you purchase a safe, you risk losing your items in a fire. Unfortunately, fireproof safes can be very expensive.

While a store-bought fireproof safe is very technical and meticulously engineered, you can create makeshift valuable storage that will resist most fires by storing your items in objects that already have fireproof capacities or by building your safe or lockbox with fireproof materials.

I recommend putting valuables into a fireproof bag, like this one, before storing them in the safe. One can be picked up on Amazon.

To learn more about different ways to construct a fireproof safe and what makes store-bought safes so effective, keep on reading. Let’s begin.

Burning House

Components of a Fireproof Safe

Fireproof safes are generally much larger on the outside than on the inside because they have thick insulation. Therefore, it can be difficult to find a safe that will be large enough to hold many belongings because you will need a very large space to store it and will have to account for the safe’s insulation when creating a space to keep it.

Fireproof safes are constructed of a steel body with two walls. The inside of these walls is defined by a fire-resistant composite that fills the space between the walls. When heated, compounds in the composite will release water vapor channeled into the safe through vents. 

This vapor serves to regulate the internal temperature of the safe and create a pressure seal against the heat of the fire. However, it is important to keep in mind that the humidity from the vapor can be very damaging to internal documents, so vents are inserted to allow steam to escape into the surrounding flames instead of damaging your documents.

Vents are placed throughout the safe, in the back, front, sides, and below the door. Safes usually do not have a way to attach to the wall, as any drilling would compromise its fireproof abilities. To keep your safe away from burglars, you could make it very large so they cannot remove it or keep it in a wall or other hidden location.

If you want to create your own fireproof safe, you have several options. However, you should keep in mind that the most effective and high-tech safes can only be found through purchasing. Store-bought safes are thoroughly tested and can withstand higher temperatures than homemade safes. These safes will be more expensive, depending on how long they promise to be fireproof.

For example, this Honeywell Fireproof Fire Safe from Amazon will last 2 hours in a fire, which is very high for a fireproof safe. This fireproofing comes at a price- you will pay quite a bit for this safe. Luckily, if you are willing to compromise more enduring or extreme heat resistance for a less expensive DIY option, there are a few ways you can create a makeshift fireproof safe.

Related How to Store Large Amounts of Cash (With Locations to Avoid).

DIY Drywall Safe

For a very cheap and easy fireproof safe, you can use drywall. Pieces of drywall can be found at almost any construction site, and this material can be used for free. A drywall safe is a great way to save money and create your own method of protecting your valuables.

To create a fireproof safe out of drywall, you need to obtain type X drywall. This is also known as fireproof drywall. It is ⅝ inches thick and has glass fibers added to the board to increase fire resistance and strength. It also contains gypsum, a substance that is used in many fireproof safes and makes it very dense. This type of drywall is rated for about one hour of fire resistance, so it should compare fairly well to many fireproof safes.

When creating your own fireproof safe, you should create a plywood box that is a little bigger than the safe you want to create. Then, frame two layers of type X drywall inside the safe to create an internal barrier of drywall. You can put your items directly into this new frame or put them in a lockbox or waterproof bag for extra protection.

To keep your items locked, it is recommended that you create a lid on the plywood section of the box that can be opened. Create a latch and add a lock to hold the latch shut. This should make sure nobody can access your belongings. Finally, you can cut small slits beneath your safe’s lid to create a vent that will release humidity created by drywall’s gypsum into the fire.

For the next two, you won’t really build anything. Even so, I still included them because re-purposing something else is the easiest way to do this without going to a great expense.

Using Your Fridge

Closeup of man hiding money in refrigerator

For a very easy makeshift safe that will resist some fire, you can use your fridge. Fridges and freezers are much more likely to survive a house fire than other appliances and belongings. If you want to create a fireproof safe without any extra expenses, you can do this as a fridge or freezer owner.

To turn your fridge into a DIY safe, simply put your items in a waterproof bag and seal it. You can then hide them in a disguised container, such as an empty ice cream tub, and put them in the freezer. That way, if a thief sees the container, they will not be likely to check for your valuables inside. Furthermore, a thief is unlikely to look for valuables in your freezer anyway, so it will be difficult for them to find your stashed items.

While a freezer will keep your items safe, there are a few situations in which you should not use a freezer. For example, if you want to store items with specific temperature needs, they may not do well in the freezer. However, if your items can last in the cold, storing them in the freezer can offer a degree of fireproofing while keeping your belongings out of thieves’ grasp.

Related How to Protect Cash From Fire (7 Easy Methods).

Fire Chests

To use a fire chest as a fireproof safe, you should find a fire safe that is rated as a media chest. This means it will protect magnets, photos, paper, and other media. It should keep the fire out and maintain an internal temperature of about 150 degrees F, so your items will not burn. Furthermore, this type of chest usually comes with a lock built in for security. Here is the one I recommend.

However, even a locking fireproof chest is not safe- you may need to add extra protection. First, the internal parts of a fire chest can become very humid, and you may want to put your valuables in a water-resistant and fireproof bag and seal it to ensure the humidity does not damage it. Here is a really good one, also found on Amazon.

Secondly, if you are afraid of burglars or simply want to maximize protection, you can put your valuables in a small, non-fireproof safe for extra protection and put that safe in the chest. This practice would maximize safety by requiring thieves to break through two sets of locks rather than just the fire chest’s lock.

If you put your items in a waterproof package, put that package in a small safe, and place that safe in a fireproof chest, you will have a makeshift fireproof safe that will probably be cheaper than a standard fireproof safe. 


Overall, fireproof safes are extremely complex but can be loosely replicated by creating a lockbox with a drywall exterior. Furthermore, for a safe that is well-disguised but does not have a lock, you can use everyday storage containers in your freezer to protect against small fires. Finally, for multi-layer fire security, you can use a small safe in a fireproof chest with a lock, creating fireproof storage that requires cracking two codes to access.

After all this, if you decide to just buy a safe. I recommend getting this one. It’s reasonably priced and effective.

Thanks for reading!

For more, don’t miss How To Bury Money (Without It Rotting).