A cutaway of a London house and garden, with a small protected room below ground.

Bunkers and protected basements in London.

Concept visualisation · a protected room below a London gardenConcept visualisation

A specialist subject, handled plainly. What can be built, what it depends on and what no basement can promise.

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A protected room, inside a normal basement.

A private bunker is a small reinforced concrete room inside a London basement. We are NU Projects, design and build in Fulham SW6 since 2010. We look at this as a specialist service, with specialist engineers. Call 020 7731 6841 for a private conversation.

Some clients ask us about nuclear bunkers. Planning rules in prime London normally allow one storey below ground. So the honest answer is rarely a deep bunker. It is a modest, dark room, built into the basement from the first drawing.

The UK has no current standard for this. Swiss and Finnish shelter rules are the clearest published reference. They are not UK law. A specialist engineer decides how they apply to your house.

What no basement can promise.

We will be plain about this. No home can promise survival from a nuclear attack. Close to a detonation, or in a mass fire, it may offer little.

A protected room can reduce some risks. It can reduce exposure to fallout, distant blast and some airborne hazards. It only protects the people already inside it.

Filters do not remove carbon monoxide or fire smoke. A fully sealed room lasts hours, not days. Be careful of anyone who says otherwise.

How a protected room is built up.

These are concept visualisations, not a specification or a real project. We do not publish structural drawings. Every house differs, and specialist engineers set the design.

The wall

  1. 1Painted plaster room face
  2. 2Dimpled drainage membrane
  3. 3Reinforced concrete wall
  4. 4Steel reinforcement, on both faces
  5. 5Underpinning or piled retaining wall
  6. 6London clay

Concept visualisation

The floor

  1. 1Stone floor finish
  2. 2Screed with underfloor heating
  3. 3Insulation
  4. 4Drainage membrane and channel
  5. 5Reinforced concrete slab
  6. 6Steel reinforcement over a concrete blinding
  7. 7London clay

Concept visualisation

The roof

  1. 1Garden soil and lawn
  2. 2Waterproofing sheet
  3. 3Thick reinforced concrete roof slab
  4. 4Steel reinforcement, with insulation below it
  5. 5Finished plaster ceiling

Concept visualisation

The door is part of the structure. It is ordered before the concrete is poured.

The door

  1. 1Finished timber door face
  2. 2Heavy steel door with a gas seal
  3. 3Steel frame, cast into the wall
  4. 4Reinforced concrete wall, with steel wrapped around the opening

Concept visualisation

Access points decide whether it works.

Every opening is a weak point. So a protected room has few openings, and each one is designed.

The way in. A steel door is cast into the wall. Its frame is tied into the steel. A good security door is not the same thing.

A second way out. Rubble can block a door. This concept has an exit under the garden, clear of where the house falls.

Daylight stays outside. Lightwells and glass rooflights are holes in a protected room. So this room is dark, and the daylight belongs to the basement around it.

Fire comes first. Building regulations still apply. A fire engineer and building control have to agree how everyone gets out.

The access points

  1. 1The normal basement, as planning allows
  2. 2Anteroom with a turn, before the door
  3. 3Heavy steel door, cast in
  4. 4Small, dark, reinforced concrete room
  5. 5Second way out, under the garden
  6. 6Hatch beyond where the house could fall
  7. 7Protected air intake, away from the house

Concept visualisation

Air, power, water and waste.

Air. A filtered unit keeps the room at slightly higher pressure. That stops outside air leaking in. A hand crank is the backup. A pressure test proves the seal.

Carbon monoxide. Filters do not remove it. So the room needs alarms and a way to shut off the supply.

Power. Batteries stay outside the room, in a separate plant space. We apply PAS 63100 principles, with fire engineering advice.

Water and waste. Water is stored inside. A sump pump needs a backup and an alarm. A dry toilet covers the time when drains cannot be used.

Communication. Mobile signal may not reach the room. So it needs its own wired links and an outside aerial.

The services

  1. 1Ventilation unit with a hand crank
  2. 2Gas and particle filter, kept sealed until needed
  3. 3Blast valves where air passes through the concrete
  4. 4Carbon monoxide, carbon dioxide and pressure readings
  5. 5Simple gauge that needs no power
  6. 6Stored water
  7. 7Dry toilet for when the drains cannot be used
  8. 8Few services, each through a sealed gland
  9. 9Batteries in a separate plant space, outside the room
  10. 10Sump pump, with a backup and alarm

Concept visualisation

Not every house can take one.

The right time to plan this is before a basement is designed. A finished basement usually cannot reach the same level. A smaller room built inside it may still help.

Councils limit basement size. A listed building, a tight terrace or high ground water can rule it out. Your neighbours and party wall surveyor are part of the process too.

We start with a private feasibility review. We will tell you if your house does not suit it.

Bunkers and protected basements across London.

Where we work
Fulham, Chelsea, Kensington, St John’s Wood, South Kensington, Knightsbridge, Belgravia, Mayfair, Marylebone, Holland Park, Hampstead, Notting Hill, Clapham, Weybridge, Cobham, Oxshott, Highgate, Primrose Hill, Earl’s Court, Pimlico, Westminster, Chiswick, Putney and Barnes, Bayswater and Maida Vale, Battersea, Richmond and Twickenham, Islington, Greenwich, Dulwich, Camden, Wimbledon, Bermondsey, Brixton, Ealing, Acton, Hammersmith, Queen’s Park, Fitzrovia and Bloomsbury

What owners ask about protected basements.

Can you build a bunker under a London house?

We can plan a protected room within a basement, with specialist engineers. We will not promise it would survive a nuclear attack.

Is it the same as a panic room?

No. A panic room is for a short stay during a security threat. A protected room is planned for different hazards and a longer stay.

Can you add one to an existing basement?

Sometimes, as a smaller room inside it. The result is usually more limited. An engineer has to check the existing structure.

What does it cost?

It is a specialist service, so we cannot give prices at an early stage. We price it once the brief is agreed.

Will it stay confidential?

Yes. An NDA is available on request. We do not publish drawings of these rooms or say where they are.

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