How to Build a Storm Shelter in a Pre-Existing Home

Find the safest area in your home to build your shelter. This room should be as low as possible, either on a ground floor or in the basement, and have no windows. If the room has windows, take them out and fill in the hole with plywood.

Bolt steel strapping plates to studs. This allows you secure the studs to the foundation.

Anchor studs to the concrete slab. If your house is not on a concrete slab, you may want to consider pouring a concrete foundation to the floor of your safe room. This adds weight to the room and gives you a strong structure to attach the studs to.

Reinforce existing walls. You should have two layers of 3/4-inch plywood to strengthen the walls, the Federal Emergency Management Agency, or FEMA, states. Secure the plywood to the walls with nails.

Install a steel door frame and attach door hinges. Once the frame is in place, secure the steel door and ensure it opens and closes properly. The door should have space for two to three deadbolt locks. Opt for deadbolts you can open from the inside and outside. In an emergency, you may not have time to search for a key.

Add a layer of steel sheathing to the walls. Bolt steel sheathing to wall studs, the ceiling and the floor. Use ceiling joists to adhere sheathing to the ceiling. Attach 1/2-inch drywall over the steel sheathing.

Fill in gaps with putty. Sand all rough spots with sandpaper. Paint the walls, if desired.