How to Keep Moisture out of a Fireproof Safe

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how to keep a safe dryHere at Firefighter Garage we like the idea of getting a fireproof safe to protect our belongings. The right safe can help protect valuable items are secure in the case of a residential fire.

And you can take a look at our picks for the best fireproof safes in this review if you’re on the lookout for a new safe for your home.

But we’ve seen a lot of questions about why their fireproof safe (and even their waterproof safe!) is collecting moisture – on this 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 own sealed ecosystem. (For more on keeping gun safes dry, see our discussion in our review of the best fireproof gun safes).

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

Why do safes gather moisture, mold and mildew?

Fireproof and waterproof safes are designed to be airtight. They keep the bad stuff out – but they also keep some of the bad stuff in, too!

Anything in your safe – from air to wood to paper to any item that’s sitting around in your safe is likely to contain moisture. Over time, that moisture vapor may start to coalesce and form condensation in your safe.

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

…But not perfect 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 out is simply airing out your safe. Take it outside, wash it, and let it sit in the sun with the door open for a few hours.

When you’re washing it, try to use a disinfectant like eucalyptus to expel any existing mold and mildew.

If you can’t take your safe outside or have it secured somewhere such as under the bed, you can still clean it where it’s sitting and let it sit there with the door open for a while. Open your windows as well to let some fresh air come in and freshen it up.

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

2. Use a Cup of Dry Rice

Dry rice is a natural desiccant – meaning it absorbs surrounding moisture and water vapors over time. This can help decrease the amount of humidity in the air in your safe. Unfortunately this is not nearly as useful as silica gel (see later in this article) but 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.

3. Use Baking Soda

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

Again – keep in mind that this is far less effective than silica gel, so 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. A bag of silica gel will be able to keep the relative humidity of your safe down for up to 3-4 weeks before it needs ‘recharging’.

You might even notice some non-rechargeable silica gel packs are provided in fireproof document bags when you receive them.

To recharge silica gel, you heat it up to over 300 degrees Fahrenheit for a few hours to let the water evaporate back out of the gel (but of course – not into the safe!) Different dehumidifiers have different methods of dehumidification, but the most common ones are:

  • Using an internal heater, which is activated 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)
  • Placing it in the microwave.

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

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

5. Use an Electric dehumidifier

You can also get electric dehumidifiers. These don’t have silica gel in them, but instead they filter the water vapor out of the air electronically.

Unfortunately the big downside of electric dehumidifiers is they need to be plugged into a wall socket at all times. This means you’re going to need to have power coming into your safe. This is pretty uncommon and only really seen in high-quality safes (Steelwater – a gun safe company – has some pretty good ones that have this option).

How to Protect the Valuables in a Safe

An additional step you might want to take is to protect the valuables in your safe from possible water damage. We personally place all our items in a box or bag inside the safe so they’re protected from water accumulation on the floor of the safe.

A simple box that stands on its own legs can often be enough to keep valuables safe from mildew if it happens to start accumulating on the floor of the safe.

Final Thoughts

Safes such as 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. Every now and then, take them out and recharge them, before throwing them back in. It’s a much better method than having to air your safe out regularly, and makes maintenance a breeze.

Unfortunately the risk of accumulation of condensation means valuable papers may get water damaged. Even if you have a dehumidifier in the safe, we would also protect documents from water damage by putting them in a file or zip-lock bag that will give them added protection.

But remember, this article has shared our opinions and a range of examples for our circumstances only, and is based on our online research. It does not constitute advice, professional or otherwise. Your circumstances or experiences will differ from ours. Make sure you do your own research and due diligence and adhere to the rules laid out in our terms and conditions and disclaimer.

Good luck!