fireproof corner in basement?
We often design and build “safe rooms” in custom homes. Safe rooms have several requirements: 1) structurally secure, 2) fire protection, 3) temperature and humidity control,
You are requesting information about fire protection only. However, it might be important to have a space that can protect you structurally in case of a severe wildfire AND keep documents in good condition year round.

Structurally, reinforced concrete block is an excellent choice for walls, but you’ll need a suitable ceiling. I’d recommend a “heavy timber” ceiling covered with several layers of gypsum board or a structural concrete slab.

Fire protection is based on “hours of protection”. That is to say, all materials are given a fire rating depending how long you need to keep a space safe. The Code requires a 1-hour rating between the garage and a home, which is about how long it takes to get everyone and everything important out safely. I’d recommend 4-hour protection, but you can’t obtain a 4-hour rating with wood framing. (You’ll need concrete block and/or concrete.)


You can buy fire doors that have fire ratings too.

If you add a duct into your new fireproof space, you’ll need to install a fire damper that shuts off during a fire. Very common, but you’ll need other means of oxygen if you plan on having the room being a place of rescue.

Floor construction is less important, but using a non-combustible material like a 4” concrete slab on grade would be appropriate. (Make sure ground water and water table is accounted for and the area is adequately drained with a french drain.)
Depending on where you live, access to fire protection, etc. will help you decide how secure and how much fire resistance is required.