Pick a shelter type, how many people it needs to hold and where it would go. The calculator sizes the shelter at FEMA's 3 square feet per person for a home tornado safe room, shows the published list price for a unit that size, sets it next to a national installed range, and lists the lines that a list price leaves out — slab, delivery, anchoring, excavation and permit. It's a starting point for a budget, not our price; your written quote comes from a site visit.
Published third-party list prices and national installed ranges, not our prices. Installation, slab, delivery, excavation and permit lines are listed but not priced because no source publishes them for St. Louis. A written quote follows a site visit.
How it sizes the shelter
| People | Minimum floor area at 3 sq ft each | Smallest common footprint |
|---|---|---|
| Up to 5 | 15 sq ft | 4 × 4 ft (16 sq ft) |
| 6–8 | 18–24 sq ft | 4 × 6 ft (24 sq ft) |
| 9–10 | 27–30 sq ft | 4 × 8 ft (32 sq ft) |
| 11–12 | 33–36 sq ft | 6 × 6 ft (36 sq ft) |
| 13–16 | 39–48 sq ft | 6 × 8 ft (48 sq ft) |
| More than 16 | — | Larger or multiple units; quoted |
Tick "wheelchair or can't stand" and it steps up one size. For up to 4 people it also shows a 4-seat compact unit, and for up to 6 a 6-seat compact unit — sized by the manufacturer's seat rating rather than by footprint.
Where the prices come from
| Type | Published list price | National installed range |
|---|---|---|
| Above-ground steel, by size | A national manufacturer's St. Louis list, $3,995–$8,985, including seat-rated compact units (page modified May 2024) | HomeGuide: $3,000–$12,000+ |
| In-ground garage | Same list: 10-seat $7,315 (more than 10 people: quoted) | HomeGuide: $6,000–$15,000 |
| Underground (yard) | Same list: 10-seat $7,525, 16-seat $9,775 (more than 16: quoted) | HomeGuide: $4,000–$20,000+ |
| Basement safe room | Steel units from the same list where they fit; built-in rooms are quoted | HomeGuide: basement shelters $4,000–$10,000+; safe rooms $4,500–$14,000 |
HomeGuide's figures come from a guide written in February 2024 (the page is titled 2026); the manufacturer's list was last modified in May 2024.
Lines the calculator lists but doesn't price
No published source prices these for St. Louis, so we show them as lines to expect:
- New slab or pad if your floor doesn't meet the manufacturer's spec.
- Delivery and placement into the garage or basement.
- Anchoring and installation labor.
- Excavation, backfill and slab restoration for in-ground and yard units.
- Building permit — required for every storm shelter in unincorporated St. Charles County; check your city or county elsewhere.
- Electrical for lighting or an outlet.
Sources
- FEMA — HMA Guide Part 12, B.8 Safe rooms — current; accessed 2026-10-10
- Survive-a-Storm — St. Louis storm shelters — pub. 2023-05-09, mod. 2024-05-17; accessed 2026-10-10
- HomeGuide — Storm shelter cost — written 2024-02-22; title 2026; accessed 2026-10-10
Get a quote
Ready to turn the estimate into a real number? Our installation crew will look at the site first. Get a quote.