How to Keep Moisture out of a Fireproof Safe

Chris HuntAbout the Author: Hi! I'm Chris Hunt, and I wrote this article. With years of experience as a former firefighter and knowledge of combustible materials, I have personally researched and compiled the information presented here. Please note that the content provided is solely my opinion and should not be construed as professional advice. Additionally, I do not guarantee the quality or performance of any of the products featured. Please be sure to review the website's Disclaimer, Terms and Conditions before using the site. As an Amazon Associate I earn from qualifying purchases (without additional cost or expense to you).

We like getting a fireproof safe at Firefighter Garage to protect our belongings. But unfortunately, fireproof safes are notorious for developing condensation. Here we review several ways to keep moisture out of a fireproof safe.

My fireproof safe smells, and it’s full of mold. Help!

The right safe can help secure your valuable items in a residential fire. Check our picks for the best fireproof safes if you’re looking for a new safe for your home.

However, we’ve seen a lot of questions about why the safe collects moisture on the inside.

Unfortunately, this is a big problem with safes. And it’s even worse with fireproof and waterproof safes.

Many gun owners, in particular, have this issue because fireproof gun safes tend to have their sealed ecosystem. (For more on keeping gun safes dry, see our discussion in our review of the best fireproof gun safes).

So let’s dive deeper into how to keep moisture out of a safe!

Water Droplets

Why do safes gather moisture, mold, and mildew?

Fireproof and waterproof safes are airtight. They keep the bad stuff out but also retain some terrible things!

Everything in your safe (air, wood, paper, items, etc.) likely contains moisture. Over time, moisture vapor may start to form condensation in your safe.

Furthermore, safes are dark and humid spaces – perfect for growing mold, fungus, and mildew!

… But not ideal for protecting your valuables.

How to keep moisture out of your fireproof safe

1. Air out your safe Regularly

The first thing you need to try is simply airing your safe. Take it outside, wash it, and let it sit in the sun with the door open for a few hours.

When washing it, use a disinfectant to expel mold and mildew. Eucalyptus scent works wonders to keep the bad smell out!

If you can’t take your safe outside because it’s secured under the bed, you can clean it where it is. You must let it sit with the door open and allow some fresh air.

Unfortunately, you’d have to air your safe once every few weeks – which isn’t practical for most people. That’s why it’s best to get a more permanent solution – check these out below.

2. Use a Cup of Dry Rice

Dry rice is a natural desiccant that absorbs surrounding moisture and water vapors over time. This inexpensive solution can help decrease the humidity in the air in your safe. Unfortunately, this is not nearly as useful as silica gel (see later in this article). Still, it’s good enough to get you started.

But it’s probably best to buy some silica gel packs as soon as possible to replace your cup of dry rice.

Cup of Rice

3. Use Baking Soda

Baking soda is another natural desiccant. It will absorb the moisture in your safe and hopefully reduce the relative humidity. It’s best to keep the baking soda in a bowl and place the bowl in the safe. Putting it straight on the safe floor can be hard to scrape off a surface.

Again – keep in mind that this is far less effective than silica gel. We recommend you use it as a temporary home remedy until you can make it to the shop to get yourself a proper dehumidifier.

4. Use Silica Gel Dehumidifiers

Silica gel dehumidifiers are probably the best solution out there at the moment. Silica gel is a desiccant that can absorb up to 40% of its weight in water vapor. So a bag of silica gel will keep the relative humidity of your safe down for up to 3-4 weeks. After that period, it’ll need ‘recharging.’

Manufacturers sometimes provide non-rechargeable silica gel packs when buying fireproof document bags.

To recharge silica gel, heat it to over 300 degrees Fahrenheit (ca. 149 °C) for a few hours to let the water evaporate. Different dehumidifiers work with a variety of methods, but the most common ones are:

  • Using an internal heater, which activates by plugging it into a wall socket
  • Placing it in the oven (beware – oven rechargeable products can’t have plastics, etc., in them that will melt)
  • Putting it in the microwave.

When you get your dehumidifier, you’ll get some advice on using it, and it’s best to follow the manual.

Quick Tip: Check out our comprehensive review of gun-safe dehumidifiers. In that article, we find the Hornady Rechargeable Dehumidifier as the best safe dehumidifier on the market. Click here to check it out on Amazon.

5. Use an Electric dehumidifier

Electric dehumidifiers don’t have silica gel in them. Instead, they filter the water vapor out of the air electronically. So, technically, they are the best to remove the moisture inside the safe.

The downside of electric dehumidifiers is that you must always plug them into a wall socket. We catalog this as a downside because you need electricity inside the safe. Unfortunately, this is uncommon and only seen in high-quality safes (Steelwater – a gun-safe company – has some pretty good ones with this option).

How to Protect the Valuables in a Safe

You might want to take an additional step to protect the valuables in your safe from possible water damage. We place all our items in a box or bag inside the safe to protect them from water accumulation on the safe floor.

A simple box that stands on its legs can often be enough. It will keep your valuables from mildew if they accumulate on the safe floor.

Final Thoughts

Sentry Safes that are fireproof or waterproof are notorious for developing condensation and mildew. It’s a constant battle.

The best solution we have come across is silica dehumidifiers. They are inexpensive. Plus, you recharge them every few weeks before throwing them back in. It’s better than airing your safe out regularly, thus making maintenance a breeze.

Unfortunately, the risk of accumulation of condensation means valuable papers may get water damage. So, even if you have a dehumidifier in the safe, it’s best to protect your documents. It’s best to put them in a file or zip-lock bag. This tip will give them added protection.