How they work
An in-ground shelter is a steel or precast concrete unit installed below grade in your yard, with steps and a tested door or hatch at ground level. The surrounding earth helps shield you from wind and debris.
Does your lot work?
In Middle Tennessee's Central Basin, limestone bedrock is often close to the surface, and karst features like sinkholes are common. Before you commit, an installer should check:
- Depth to rock. Shallow rock may make excavation costly or impractical.
- Drainage. Water can collect in low spots and travel through fractured rock. Avoid sinkholes, drainage paths and areas that pond after rain.
- Distance from the house. You'll be going outside during a warning, maybe at night in heavy rain. Closer is better, with a clear, lit path.
- Equipment access for the excavator and delivery.
- Utilities, via a Tennessee 811 locate.
Steel or concrete?
Steel units are lighter and easier to place in tight yards. Precast concrete units are very heavy and need larger equipment, but resist corrosion well. Either can meet ICC 500 if the specific model, including the door, has been tested.
Moisture and buoyancy
Wet soil can push upward on a buried shelter. Ask how the shelter is anchored against that, how it's waterproofed, and how ventilation keeps it from getting musty.
When another type is better
If rock is shallow, drainage is poor, or someone in your home can't manage steps or a trip outdoors, an above-ground safe room is often a better fit.