Nuclear bunkers and Fallout Shelters.

London specialist Basement Company

A Nuclear bunker not only provides physical protection as an air-raid or bomb shelter would, but also protects from the impact of radioactive debris or ‘Fallout’ as a result of a nuclear explosion.

When a nuclear bomb goes off, matter is vaporised in the fireball produced from the initial explosion and is exposed to Neutrons. The matter absorbs these neutrons, and becomes radioactive. This radioactive material condenses in the rain and forms dust and a light sandy material which emits alpha and beta particles, as well as gamma rays. This is called ‘Fallout’. This radioactive material falls to the ground, subjecting anything within the line of sight to radiation, for a considerable period of time. The same Fallout can also occur after an accidental nuclear explosion, not just the result of tactical Nuclear weapons or larger strategic Nuclear missiles which are devastating in their scale and impact.

A Fallout Shelter is an enclosed space designed to allow people to take shelter and minimise exposure to the harmful fallout until the radioactivity has decayed to a safe level.

Underground BunkersDoor of a public fallout shelter in Switzerland (2014).(CC BY 2.0)

A fallout shelter includes shielding in its construction to reduce gamma ray exposure. The required shielding can be accomplished with various materials including lead, concrete or packed earth, but the thickness required will vary depending on the material. The thickness will need to be enough to reduce the gamma rays by approximately 1024 times in order to provide protection.

Whilst it is possible to have a nuclear shelter in a building above ground, it is normally more suitable and cost effective to construct them underground, saving space and allowing the earthworks to contribute to the protection and shielding of the bunker. Because of the initial shockwave from a nuclear blast shelters need to be located away from other buildings or large trees that may collapse on the shelter.

Blast Doors are also included to access the shelter. They are specifically designed to take the impact of the shockwave from a nuclear blast and provide the necessary shielding. Their location needs to be carefully considered to reduce the gamma ray exposure.

In order to make the shelter habitable, internal air cooling systems need to be included and additional filtering and conditioning of air can also be included depending on the specification required. The shelters need to provide suitable accommodation for at least two weeks for a specified number of inhabitants, without having to exit, so provision for enough stored water and rations needs to be considered. Sanitation is also required, often through the use of a septic tank as mains services would not be able to be relied upon in a nuclear attack.

Example designs of a Subterranean Spaces Nuclear Fallout Shelter. ©Copyright Subterranean Spaces

nuclear bunker

If you are looking to install a Nuclear bunker to protect yourself for a possible nuclear attack, Subterranean spaces can provide specialist underground nuclear bunkers for domestic clients as well as commercial or public sector projects.

Please contact us on 020 3086 8816 or 07779 062227, or email us at

Want more information?

Find out more about Nuclear Bunker construction in our Blog post: "Constructing a Nuclear Bunker - From Vision to Reality"

Bore hole testing

Bore hole testing with a Percussion Rig allows us to test the ground down to about 15 metres. Engineers need know exactly what type of soil is beneath the proposed location of the Bunker or underground development, it could be clay, chalk, rock, lime etc. This also identifies where the water table is. This is the most important factor in subterranean construction. When creating a structure underground you are increasing the weight of that area, if the structural design is not done correctly then the new underground development can crack, move, or even sink. Bore hole testing is fundamentally important to the successful design and construction of the Bunker or any subterranean project.

Bore hole testing for Nuclear Bunkers

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