How to Build a Secret Underground Room

You never know when you'll need the security of a secret underground room. Whether you want a secure place to hide your valuables or take shelter during a tornado, a secret underground room will offer privacy from prying eyes and a safe haven.

Build a room no one knows about.

Step 1

Plan to enter your secret underground room from your basement. If you don't have a basement, you can still build one but the access will be less secure.

Step 2

Excavate the outside soil where you want the room to be. Placement is important because you want to hide the evidence of the room underneath a large porch or a deck. It's tricky to try to cover the roof of the room with soil because it will eventually biodegrade and settle.

Step 3

Form and pour concrete reinforced walls, using rebar in teh walls and putting conduit in the forms before you pour to allow access to wiring later. Plan for either a ceiling or wall air vent at this time and frame it in.

Step 4

Pour the floor and install a steel-reinforced ceiling. If you're really worried about someone getting in, you can frame and pour the ceiling, too but as long as you hide it under a deck, it's not that important.

Step 5

Frame the access from the basement by installing paneling on the entire wall and putting a single piece of paneling on the back of the secret underground room door. Make sure the panel fits well when the door is closed.

Step 6

Don't get a permit to put in the room. This might be a sticking point for you. In some rural areas, permits are not required but in many places you must have one. As long as you have a tall fence and tell your neighbors you're just installing a patio and a new deck, they may not notice.

Step 7

Keep the secret of the underground room until after you sell the home. Then go back and inform the new residents of their "bonus" room.