Construction strategy
Atomic bomb shelters, and air-raid shelters essentially consist of a thick reinforced concrete shell, with their entrances and exits secured by special blast doors.
For a secure air supply, the protective spaces are equipped with a specialized ventilation system with gas filters, which can be operated both electrically and manually in case of an emergency.
Additionally, protective spaces are equipped with an emergency exit in case the exit through the protective space door is blocked.
Main elements
1. Shelter shell
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made of reinforced concrete
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2. Primary access stairs
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3. Shelter sluice/lock
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blast door
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pressure door
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4. Emergency exit
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blast hatch
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5. Shelter ventilation system
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explosion protection valve with pre-filter (air inlet)
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overpressure/Explosion Protection Valve (Air Outlet)
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ventilator
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gas filter (activated carbon filter)​
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6.Toilet block with dry toilet​
Construction within the building
The most cost-effective option for building a shelter in a private residence is when the shelter is integrated as a separate "basement compartment" during the construction of the new building as part of the structural work.
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Since the exterior walls of the basement are already being concreted during the construction of the new building, the walls in the area of the shelter can be dimensioned thicker without much additional effort.
At the same time, the additional shelter walls, the blast door, the blast cover with emergency exit, and the necessary wall penetrations can be planned and concreted.
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Before the basement ceiling/shelter ceiling is built, the blast door, the pressure door and the blast lid can be filled with concrete. The advantage is that the reinforced door (200 kg when unconcreted) can be positioned and installed directly in the basement using the construction crane.
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The shelter is therefore directly in the basement of the house and can be used as a cellar compartment or as a safe storage place in times of peace.The shelter is therefore directly in the basement of the house and can be used as a cellar compartment or as a safe storage place in times of peace.
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The integrated shelter in the basement as part of a new building is the simplest and most cost-effective way to build a shelter.
Construction outside an existing building
If you want to construct a comprehensive shelter room according to Swiss standards in your existing house/building, shelter rooms can be realized through subsequent extensions to the basement.
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Alternatively, there is the option to build a shelter room independently of existing buildings on the property. The new construction can, for example, take place in the garden or simultaneously be used as the foundation of a garage.
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The construction of a shelter room outside an existing building is more complex and expensive than building a shelter room during the construction of the house.
Conversion of an existing room
This is the case when you want to construct a bunker/shelter at your existing house/building, and no additional extension or new construction on the property is possible.
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The difficulty in retrofitting a basement lies in transporting the very heavy shelter components into the existing basement and assembling them there. In most cases, it is not feasible to transport the bulky blast door, weighing 200 kg, into the basement. Additionally, the existing basement walls are not sufficiently dimensioned to meet the requirements of a basic shelter.
When basic shelters cannot be realized, temporary shelters offer an alternative.
In a temporary shelter, an existing basement room is reinforced and converted into a bunker/shelter. The weakest points in the basement are the doors and windows. The doors of existing basements are rarely airtight and provide no protection against pressure and explosions. There is a particularly high risk associated with window glazing. Even with slight pressure loads, windows can shatter, propelling glass shards into the room.
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With the help of special protective covers, basement windows can be equipped to protect shelter occupants from pressure waves, (glass) fragments, and, in combination with a ventilation system, from nuclear, biological, and chemical warfare agents in the event of an emergency.
In peacetime, the lid is open, allowing the window to be used normally.
During disasters or attack phases, the light well can be filled with sandbags and the cover sealed. The cover can optionally be equipped with a connection for a NBC fresh air ventilation system, allowing outside air to be drawn in and filtered. In addition, the cover provides protection against pressure waves, (glass) fragments, and, in combination with a ventilation system, against nuclear, biological, and chemical warfare agents.
If the building is (partially) damaged by external forces, preventing individuals from potentially leaving the basement space, the cover can be opened, the sandbags removed, and the building can be exited via the light well (emergency exit).
The doors for converted basement are usually replaced with gas-tight, pressure-resistant sheet steel doors. For the dual use of the shelter as a panic room, these doors can also be planned and installed as burglary-resistant and bullet-resistant.
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If a higher level of protection is desired, interior walls can be built up with concrete formwork blocks and the ceilings can be reinforced with supports. Pressure doors and blast hatches are usually installed, which offer better protection against radioactive radiation as well as conventional and secondary weapon effects.
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The following table provides an overview of the scope of protection and the construction methods of shelters and converted basements:
Overview of shelter categories:
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The table illustrates that the basic shelter, compared to basement conversion, provides the most comprehensive protection. The conversion to a makeshift shelter with a special door, ventilation system with gas filter, and the sealing of windows allows for significantly better protection than a conventional basement provides. The costs depend heavily on the specific circumstances and the desired level of protection.
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For Category 1 nuclear shelters/shelter structures, the minimum component thickness of the shelter shell must not be less than:
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30 cm minimum floor/slab thickness
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30 cm minimum external wall thickness
6 steps to your own bunker / shelter
1. Advice
Simply contact us using the contact form and receive non-binding and discreet advice for your own shelter. Your individual conditions and preferences will be determined.
Based on this, we can provide you with an offer for the necessary shelter components and shelter planning.
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2. Concept Development and Planning
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Based on your building floor plan, we design a cost-effective arrangement of the shelter envelope and position the shelter components in a sensible layout.
We will liaise with the planning department on your behalf. As we are also the RIBA architects, we can modify your existing design to incorporate the shelter seamlessly. If you have already engaged an architect for your house, we can coordinate the project collaboratively between our team and your architect.
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3. Building Control and Structure Engineer calculations
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We will prepare the projects to meet all UK building regulations necessary to obtain the Building Control certificate.
Furthermore, your shelter will be designed in accordance with the latest Swiss standards (TWP and technical specifications TPH), taking into consideration conventional, nuclear, chemical, biological, and secondary weapon effects.
Subsequently, our structural engineer will conduct a static calculation for the planned shelter, taking into account the building statics, in accordance with the current Swiss directive TWK2017.
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The calculation is carried out according to the leading hazards of mechanical effects (air blast, ground shock) from nuclear weapons, with a load case of 100 kN/m², protection against primary radiation, nuclear radiation from fallout, mechanical effects from fragments and shocks, fire effects, and chemical warfare agents.
For this purpose, you will receive specification and SE design with reinforcement details including steel schedule for your individual construction project.
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4. Delivery of the shelter components
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All necessary components for the construction of the shelter are inspected, packaged, and shipped in Switzerland.
Subsequently, the shelter components will be delivered to the installation site by a transport company on the agreed-upon date, following direct coordination.
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5. Concrete work and installation of wall components.
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Based on the setting out plans, construction details and specifications provided by us, a construction company of your choice can form and concrete the shelter envelope with finishes.
For the installation and concreting of the blast door and hatch, the construction company will be provided with relevant installation instructions and assembly videos by us.
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6.Assembly of the shelter components
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Once the basic structure, including electrical work, is completed, all additional components such as the ventilation system, toilet cabins, furniture, etc., can be assembled and installed.
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The installation of these components can be carried out either by one of our installers, a local installer of your choice, or, depending on your craftsmanship skills, by yourself. Comprehensive installation instructions will also be provided by us.
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