Your basement or cellar as a shelter: how to set it up for a few hours or a few days
How to turn a basement or cellar into a shelter for air-raid alerts, tornadoes or radiation warnings: what to check about the structure, air and flooding, what to keep there (water, light, a toilet, places to sleep) and what never to do.
In short
- A basement surrounded by earth protects well from debris, high winds and, partly, radiation; it does not protect from floods.
- First check the structure, ventilation, exits and whether it floods.
- You need water, light, a radio, a first aid kit, somewhere to sit or sleep and a toilet solution for everyone.
- Never run a generator, grill or open-flame stove in a basement: carbon monoxide kills in enclosed spaces.
A real bunker costs as much as a flat. Many of us already have a space that, properly prepared, protects surprisingly well: the basement, the cellar or the storage room under the building. Surrounded by earth, it shields you from debris, broken glass, high winds and, partly, from radiation.
When a basement is a good idea and when it is not
| Danger | Basement good? |
|---|---|
| Air-raid alert, drones, missiles | Yes, the best place in the building |
| Severe storm, tornado | Yes |
| Nuclear fallout | Yes, especially in the middle of the room |
| Chemical release | No: many toxic gases are heavy and sink. Go upstairs and seal a room |
| Flood, heavy rain | No: go upstairs |
| Earthquake | Not during it; afterwards only if the structure is sound |
All about air-raid alerts: sheltering from air attacks.
Check first
- Structure: large cracks, damp that has damaged beams or the ceiling? Ask a professional.
- Two exits: the main door and, if possible, a window well or second stair. Make sure stored things do not block them.
- Air: there must be ventilation. Without it, CO₂ and humidity build up fast when several people are inside.
- Water: does it flood in heavy rain? If so, keep everything on shelves at least 30 cm (1 ft) off the floor.
- Utilities: do you know where the gas and water shut-offs and the fuse box are? Do not store fuel down there.
What to keep in the basement
For each person:
- Water: at least 4 litres (1 gallon) a day for 1–3 days
- Food that needs no cooking
- Somewhere to sit and sleep: mattress, sleeping bag or camp bed
- A blanket and warm clothes (basements are cold)
For everyone:
- Flashlights and LED lamps with spare batteries, no candles
- A battery radio, so you know when the alert is over
- A power bank for phones
- A first aid kit and basic medicines
- A bucket with a lid, bags and sawdust or cat litter for a toilet, plus wipes and sanitiser
- Bin bags
- N95/FFP2 masks for dust after explosions, see air in an emergency
- Games, books, headphones for children
- A small fire extinguisher
What never to do
- Generator, grill, camping stove or improvised heater in the basement: carbon monoxide builds up and can kill within minutes. See carbon monoxide poisoning.
- Do not block the exits with furniture or boxes.
- Do not go down during a flood or a gas leak.
In an apartment building
Your storage unit may be small, but the basement corridor or the building’s shelter can serve all residents. Talk to the building management: keep the basement clean, lit and free of clutter blocking the way, with a key easy to find. Ask your local authority whether the building has an official shelter.
No basement? Pick a room in the middle of the home, without windows, on a lower floor: the safe room.
Frequently asked questions
Is my building's basement an official shelter?
Not necessarily. Official civil-protection shelters have special doors and ventilation and are listed by the authorities. An ordinary basement is still far safer than an upper-floor flat during an air-raid alert or a tornado.
What if my basement floods?
Then it is not a good shelter for floods or heavy rain. For those, go upstairs, not down. Use the basement for air-raid alerts, storms and tornadoes.
How long might I stay down there?
For a tornado or air-raid alert, usually minutes to a few hours. After a nuclear incident, authorities may advise staying indoors for a day or two. Prepare it for at least 24 hours.
Sources and further reading
Preper is for general education and does not replace instructions from your local authorities or advice from a doctor. In an emergency, call your local emergency number.