In-ground vs garage vs above-ground storm shelters
Most families around Oklahoma City end up choosing between three kinds of shelter: a steel unit sunk into the garage floor, a concrete or steel cellar buried in the yard, or an above-ground safe room bolted to a slab. Here is how they compare. Checked November 2, 2026.
Safety is the same target for all three
A residential safe room built to FEMA P-320 is designed for 250 mph winds and to stop a 15-pound 2x4 hitting at 100 mph (FEMA P-320 (2025)). Above-ground and below-ground shelters can both meet that bar, and FEMA P-320 walks through the trade-offs between them (NSSA homeowner information). So the choice is about your house, your family and your budget, not about one type being safe and the others not.
Garage floor (in-ground) shelter
A steel box set into the garage slab with a sliding lid you can park over. Published OKC prices start around $3,300, and a 6-person unit runs about $4,500 to $6,500 (see our cost page). OKC permits it as an in-ground shelter for $99.50 (City of OKC Storm Shelter Permit page). The catch is stairs, which can be hard for older adults, and water: Texas Tech's study of Moore 2013 found flooding and worn rollers in some units (Texas Tech Moore 2013 report).
Outdoor in-ground cellar
A buried concrete or steel shelter in the yard, sometimes with a slope-top door. Published 6-person prices run about $6,500 to $9,000 (cost page). It needs excavation, yard access and a plan for groundwater. Oklahoma City asks for an engineer's flotation letter for in-ground and slope-top shelters (OKC Development Center), and the permit is $99.50 (OKC permit page). You also have to go outside to reach it.
Above-ground safe room
A reinforced steel or concrete room anchored to a slab in the garage, a closet or an addition. No stairs and no digging, which makes it the easiest choice for wheelchairs and anyone with limited mobility. Published 6-person prices run about $5,500 to $8,000 (cost page), and OKC's permit is $104.50 (OKC permit page). The slab has to handle the anchors, so ask for the manufacturer's foundation requirements (FEMA foundation and anchoring criteria).
How much room you need
FEMA's tornado minimum is 3 square feet of floor space per person in a home (FEMA P-320 (2025)), so a family of five needs at least 15 square feet.
Quick picks
- Mobility limits in the family: above-ground.
- Lowest price and a garage you park in: garage floor shelter.
- No garage space and a dry yard: outdoor cellar.
Whichever you choose, use our installer questions and run the numbers in the cost calculator.
Related: shelter costs · rebate status 2026 · in-ground vs garage · metro registries · installer questions