In most countries a building permit would be required.  Be aware that a registered building permit makes the location public and compromises the secrecy of you bunker.

Both are underground, but a bunker has minimum 1 m of ground on top of the concrete roof and is equipped with life support systems.  A basement can protect you against tornados and hurricanes, but offers only little protection against wildfires and earthquakes.  For more serious catastrophes, like riots, war and pandemics, bunkers are a much safer solution.  In case of a nuclear explosion, a basement offers zero protection, while a professional bunker allows you to survive a remote explosion and the aftermath.

An underground bunker offers protection against different types of natural disasters, like wildfires, hurricanes, tornados, vulcano eruptions, earthquakes.

In addition, it offers protection against war conditions, riots, pandemics, nuclear explosions and fall-out.

Assume it is a 800 Kiloton nuclear explosion, the typical yield of an intercontinental ballistic missile.  That is 50 times more than the bomb that destroyed Hiroshima.

A nuclear explosion of that size, at a distance of less than 1 km, means "lights out" and instant unification with the atoms of the universe, even if you are in an underground bunker.  In a radius of 5 km everything above ground will be incinerated.

However, a bunker does give you the necessary protection to survive a nuclear explosion at 3 km distance or more. 

You can store food and water for 6 to 24 months, depending of how many people are in the bunker.

The battery holds energy for 2 to 6 weeks, depending of how much energy you use. The battery can be recharged with solar panels, wind turbine and with human power generator.

War or riots can last months and even years.  A natural disaster is usually over in a couple of days.  The radiation after a nuclear explosion has diminished to safe levels after 6 weeks.  But the aftermath of an apocalyptic event can last years, while infrastructure, food and water supply, comunication and civilisation itself might be destroyed.

Apart from physical survival, it is important to take care of your mental health, using entertainment, gym and recreation equipment.  A forced stay underground, with no contact with the outside world, no windows and on a small surface, can drive people crazy and cause conflicts among the habitants.

The number of people that can stay in a bunker depends of:

• the surface of the bunker

• the number of bedrooms

• the food and water storage capacity

• the time people must stay inside.

The maximum indicated capacity for our bunkers is based on a minimum stay of 6 months, assuring sufficiant food and water supply, privacy and comfort.

The best place for a bunker is as close as possible to you everyday residence, even as a basement under your house.  When a natural disaster strikes, a crisis or a war breaks out, it is usually with very short forewarning.  Roads will be instantly blocked and travelling a distance through chaos to a remote bunker will be virtually impossible.

The bunker and the access should be secret and hidden.  After an apocalyptic event, existing shelters will be a target of looters and other people seeking food and survival.

We strongly advise to build your bunker on higher grounds, avoiding coastal and inundation sensitive areas.

You might need to leave the bunker for making repairs or searching for supplies, wearing protective clothing.  In the event of a deadly pandemic, chemical contamination or nuclear fall-out, it is necessary to decontaminate a person when they re-enter the bunker from outside, to prevent contamination inside.  

The purpose of the L-shaped access stairs is to have a minimum 1 meter thick layer of earth between the stairs and the living area, to stop gamma radiation entering the bunker interior. 

The staircase is should be accessible from your private premises, to keep the entrance discrete and secret.