How to Build a Storm Shelter in a Hill

Step 1

Excavate the hillside with a backhoe or other digging equipment. Make the excavation slightly larger than your planned shelter, allowing at least 12 inches of extra space on all sides.

Step 2

Lay a bed of gravel 6 to 8 inches deep across the entire excavation. Rake it smooth, checking it with a level to get it as even as possible. Build the form for the floor of your shelter atop the gravel. Use two-by-fours, securing them in place with stakes every 2 feet around the perimeter. Check your form to be certain it is square and level as you stake each side.

Step 3

Pour the flooring of the shelter. Add re-bar or a screen mesh to the concrete for added strength. Use a trowel or a straight edge to smooth the concrete. Let the concrete dry for at least 24 hours.

Step 4

Lay concrete blocks around the base of the flooring, leaving an small opening for a doorway. Cement each brick in place, keeping the row level and straight. Add additional rows until the wall is approximately 3 feet high. Allow the concrete to set for 24 hours.

Step 5

Pour additional gravel around the three sides of the shelter that will be concealed in the hillside. Lay approximately 8 inches of gravel, then install 4-inch, perforated PVC pipe in a continuous run around the shelter. Add 3 to 5 inches of gravel--enough to cover the pipe. This system will help draw water away from the shelter and keep the interior dry.

Step 6

Install additional rows of concrete blocks until the shelter is the desired height. Atop this wall, construct a frame for your roof by laying a sheet of 3/4-sheet plywood across the opening and building a frame around the exterior of the plywood with two-by-fours. If you're constructing a large shelter, add bracing inside the shelter to support the ceiling until the concrete is dried. Measure and cut four-by-four beams to wedge beneath the plywood. Two or three supports should be adequate for most structures.

Step 7

Pour the concrete roof/ceiling of the shelter. Once the concrete has dried, back-fill the areas around the shelter, covering as much of the shelter as possible with soil. Install a solid doorway, preferable with a metal door. Add electrical or phone lines if desired.