Capital Inflation

London’s Most Iconic Buildings are made Inflatable and the Cost of Doing it to the Entire City is Revealed

Reveal everything by hovering over London’s Most Iconic Buildings below

The Loanable content team have partnered with brilliant, emerging artist, Guangyu Li. He created a wonderland for us by making the most memorable buildings of our great metropolis appear as if they are filled with hot air. He had fun re-inventing their colour palettes and adding some imaginary structures as well. You can click on each of our 10 famous buildings and one famous park to see their incredible detail in close-up – and to discover amusing and little know facts.

Using a frankly insane amount of maths and formulas, we also try to add up the cost of re-imagining the whole of inner London – and its landmark structures – as entirely inflatable versions of themselves. As you can imagine, this requires a step in to the unknown as no one can know for certain what this would cost. But we spent an incredible amount of time trying!

We also ask you to let us know which absent building is crying out to be made inflatable and we will add the most popular choice to our cityscape. We also want to know what people think is Guangyu’s best work – and we will re-create it as a real-life inflatable and present it to the building in question.

So, how much would it cost? The total comes to a whopping £582,500,000,000

Below, we delve deeper in to our building’s and park’s most interesting, unusual and amusing facts…


The Gherkin


During The Gherkin’s construction, the body of a Roman woman was unearthed which was over 1500 years old. It was temporarily moved to the Museum of London, then returned from whence it came at the foot of the building upon its completion.

The Gherkin’s architect is the much-lauded Sir Norman Foster who was also behind iconic builds such as the restructured German Reichstag, the Millennium Bridge and the second incarnation of Wembley Stadium. Also known as “The Cigar”, The Gherkin is trumped in the most-amusing- nickname- for-a-building stakes by The House of World Cultures art museum in Berlin. Locals refer to it as “The Pregnant Oyster”.


The Olympic Stadium


Costing £500 million (which would just about get you 3 penthouses in One Hyde Park) the stadium was completed in 2011, ahead of the London Olympic and Paralympic Games of 2012. It is now home to West Ham United FC as well as hosting live music and other sporting events.

During the 2012 Olympics, 3 World Records and 4 Olympic records were broken at the stadium. During the Paralympics later that summer, 73 athletes set world records at the venue.

Queen Elizabeth Olympic Park, where the Olympic Stadium is housed, was one of London’s most ambitious and expensive development projects, costing £12 billion, taking 10 years to complete and requiring 80,000 workers.


Tower Bridge


One of London’s most iconic structures, Tower Bridge is often mistakenly referred to as London Bridge which is, in fact, about 1/5 mile upstream.

The open walkways along the top of the bridge made it very popular with pickpockets and prostitutes at around the turn of the 19th century and so they were duly closed off from 1910-1985.

In 1977, the bridge was painted red, white and blue to celebrate the Queen’s centenary.


The Houses of Parliament


Two red lines run across the floor of the Commons, separating the two sides of the house. The lines were deliberately set two sword-lengths apart so that if a member of one side of the house drew his sword, his adversary would have a sporting chance of rebuking the attack.

The Principal Doorkeeper of the Commons keeps a snuff box for MP’s seeking a mild stimulant. It is said to be called upon infrequently.

The collective buildings in which the Commons and the Lords are housed are known as The Palace of Westminster. First built in 11th century as a seat of the Monarch, they were almost completely destroyed by fire in 1832.


Richmond Park


The park has its own Police Force who, amongst other things, strongly disapprove of duck chasing. In 2012, a dog owner was fined £315 for allowing his canines to pursue a duck. Punishable acts in the park also include mushroom picking and cycling faster than 30mph.

Ducks aside, the park also provides an important sanctuary for many species of animal, including parakeets, butterflies, snakes and stag beetles.

Richmond Park is home to National Trust Property, Ham House, built in 1610. This may be said to be an unfortunate name for a venue that has theatrical productions as one of its principal concerns.


The Shard


The Shard was initially conceived as a sketch on the back of a napkin by its architect, Renzo Piano. However, as he understandably points out, this was to spare non of the rigour that lay ahead in the construction of a building requiring 54,000 m3 of concrete.

Standing at 309.6 meters (or 1,016 feet), The Shard is the tallest building in the United Kingdom and the fourth tallest building in Europe.

The Shard is one of the greenest and most energy-efficient buildings in London. It operates with a combined heat and power plant and converts fuel to electricity, considerably softening its carbon footprint.


Tate Britain


Tate Britain houses work by British masters John Constable and John Sergeant and leading 20th century British artists Francis Bacon, L.S. Lowry, David Hockney and Tracy Emin. There are also works by iconic European painters including Henri Matisse, Salvador Dali and Pablo Picasso

Amongst The Tate’s collection is Picasso’s revered work, Weeping Woman. Another version of the painting was the subject of a high profile art theft from a gallery in Melbourne, Australia, in 1986. The work was subsequently found in a railway station locker.

The record price for a work of art was set in 2017 when Christie’s auction house in New York sold Leonardo da Vinci’s portrait of Christ ‘Salvator Mundi’ for $450.3 million. It had once been sold for just $60.


The Royal London Hospital


The hospital examined the murder victims of the infamous Jack The Ripper whose crimes were also known as “The Whitechapel Murders”.

The “Royal” part of the hospital’s title was conferred by the Queen in 1990 to commemorate its 250th anniversary.

One of the hospital’s most famous employees was nurse, Edith Cavell, 1865-1915. She was esteemed for the medical help she would give soldiers in need during the First World, irrespective of whether they were British allies or enemies. To much condemnation, she was executed by a German firing squad for helping allies flee occupied Belgium.


St Paul’s Cathedral


It was the tallest building in London for over 250 years, between 1710 and 1962.

To raise awareness for equal voting rights, suffragettes planted a battery-powered bomb underneath the Bishop’s throne. However, the bomb was defective and failed to go off. It wasn’t until 1918 that women were allowed to vote and it was 1928 when full voting equality was introduced.

St Paul’s Cathedral plays host to rotating roster of art installations by artists including Yoko Ono and Anthony Gormley.


One Hyde Park


In addition to having the world’s most expensive apartment, there are 3 occasions when properties in the building have sold for £130 million or more.

The building and its residents remain largely enigmatic. Its security, though, is as on-point as you would expect with the corridors patrolled by bowler hat-clad men trained up by the SAS.

The development is the brainchild of property developers, The Candy Brothers. Having started out with a £6,000 loan from their parents, they have gone on to amass a multi-billion pound property portfolio.


The London Eye


Since opening in 2000, it has welcomed over 80 million visitors.

It once became a pop up restaurant during the London Food Festival with some of its meals going for an eye-watering $30,000 per head.

When erected in 1999, it was the world’s tallest ferris wheel, standing at 135 meters (443 feet). It was surpassed by the Star of Nanchang in 2006 in southeastern China.

How did we work this out?

Even the most detailed property and construction statistics available wouldn’t be able to tell you exactly how many buildings exist in London at any one given time. After all, what about ones that are only half-built? How many are getting knocked down per day? Do festival tents count? So we have made some big approximations, and cut some corners – but here is a rough idea of how to find out what a bouncy-castle London would cost.

According to, the total area of inner London is approximately 327,975,000m², or 327km². This is divided into 42,118,000m² of domestic buildings and 31,053,000m² of non-domestic buildings. Emu Analytics has some nifty data software that shows you the total number of buildings and their heights and density within a given area. Using the London statistics, we were able to draw a rough map of inner London, and calculate that it encompasses approximately 116,375 buildings in total, with the tallest structure reaching 286m. All this information is available thanks to , a non-profit which exists to help provide equitable access to statistics and other planning-based resources.

So now we have the total area of inner London that’s been built on, the number of buildings, and the average height of a London building. To get a rough estimate of the surface area of these buildings, we take the average height of inner London buildings, and and apply the formula:

Surface Area = (2 x length x width) + (2 x length x height) + (2 x height x width)

If we assume that the length and width of each building is the same, then the length and width of each side is equal to the square root of the average square metres of each building (see below for figures). The height is the weighted average of all the buildings in the height brackets given by the Emu software.

Plugging in the numbers we get:

Total built-on land: 42,118,000m²+ 31,053,000m² = 73,171,000m²
Average square metres of each building = Built-on land / number of buildings = 73,171,000m² / 116,375 = 628m².

Surface area of each building:

Length and width of each building = Square root of 628 = 25.1
Surface area of each building = (2 x 25 x 25) + (4 x 25 x 14.275 ) = 2677.5

Surface area of each building x number of buildings = 2677.5 x 116,375 = 311,594,063m²

This leaves us with 311,594,063m² of inflatable material to blow up. Yikes. This is actually equivalent to 312km² – which is nearly the size of inner London itself! Another way to look at it, is that if all the walls and roofs in London were to fall, the debris would cover the whole of inner London. The only reason we wouldn’t have a surplus of material, are the rivers, roads, parks and other unused land included within the area.

Right! Now down to the cost of the inflatable materials themselves. For this we turn to the experts in custom bouncy castles AJL UK; manufacturers of bouncy castles in the UK and abroad. Want to build a castle with your 4yr old’s face on it? They can do it. The info they gave us is as follows:

We would need 311,594,063m² of inflatable material to blow up.

Number of man hours to create 116,375, 25m x 25m x 14m buildings: 260man hours x 116,375 = 30,257,500 hours of labour. This is approximately 105 years worth of work for a team of 100 working 5 days per week. If we pay our imaginary workforce £15 per hour, that comes to £453,862,500.

Cost of flame-retardant PVC per square metre and other materials: £2.50 per square metre.
With 311,594,063m² to inflate, that comes to a towering £778,985,157.5 in materials.
We would need 465,500 x 1.5hp Blowers to keep the buildings afloat. Each of these is £120 and this adds another £55,860,000 to the hefty bill.
Each blower uses 0.9kw per hour so multiply this by 465,500 and at 12.827pence per kWh (The average cost of energy in the UK) To run the blowers, the cost for electricity comes for this to operate 24hrs/day for a year would cost £581,174,266,733/year.

This gives us a grand total of : £582,462,974,390 and 50p

Don’t forget, if you’re looking to start a bouncy castle hire business, contact – the bouncy castle manufacture experts who gave us all the data we needed to find out how we could inflate London!

The Gherkin

The Gherkin is a more complicated calculation owing to its egg-like shape that rests on a square base. For this we used the height of the building (180m), and made that the top height of the egg shape 173m, keeping the lower half as 6.405m. Largest floor external diameter (lvl 17): 56.15 m.

Volume: 296,164m3

SurfaceArea: 27,007.6m2

Cost to inflate and build:

Materials: £67,519.05

Number of blowers: 135 = £16,200

Number of Man Hours: 794 *15 = £11,915

Amount of electricity: £13,652,289

Total: £13,747,923





h = h1 + h2

b = 2 * a

if a > hi: Ai = πa * [ a + hi² / √ a² – hi² * arsinh( √ a² – hi² / hi ) ]

if a < hi: Ai = πa * [ a + hi² / √ hi² – a² * arcsin( √ hi² – a² / hi ) ]

if a = hi: Ai = 2πa² (hemisphere)

A = A1 + A2

V = 2/3 * π * a² * h

pi: π = 3.141592653589793…

St. Paul’s Cathedral

Surface area can be found by using the 146m x 76.2m x 53m(without dome) = 316774m²

Total SA: 316774m² + 4124.91(dome)

Total Volume:  589,635m3 + 31,684m3(dome)

Man Hours: 9,483

Cost of Man hours: £142,245

Number of Blowers: 269.5

Cost of blowers: £32345.7

Inflatable material : £802247

Cost of electricity: £27,254,014

Total: £28,231,121


The Shard

Sits on 27acres of land in Southwark, has 11,000 glass panels, and reaches a height of 309.6metres at its apex. The area of glass on the building is equal to eight football pitches, and there are 44 lifts (Or 306 flights of stairs, if you’re fit), that service the building. The area it sits on is

Its roughly pyramidal shape means that it would use the formula: V=lwh/3

The total amount of (recycled!) glass used was 56,000sqM – which would cost £140,000 in inflatable material.

SA: 56,000m2

Volume: 410,000m3

Man Hours: 1,647

Cost of Man hours: £24,705

Number of Blowers: 236

Cost of blowers: £28,373

Inflatable material: £140,000

Cost of electricity: £23,866,224

Total: £24,215,479

Royal Hospital

Approximate volume:1,786,908m3

If you were to inflate it just with your own breath, you would have to exhale about 787184 times. This is about 46 days’ worth of breathing.

37mL per Kilogram – average tidal volume

2.27L per breath

125.85 x 38.9 x 83.3 = 407800.5645V

SA: 37238.480

122 x 80 x 83.3 = 813008

SA: 53173.200m2

148 x 85 x 45 = 566100

SA: 46130m2

Total SA: 903,419

Materials: £2,258,549

Man hrs: 26571  Cost:  £398,567

Blowers: 816  Cost:£98,024

Electricity cost: £82,520,503

Total Cost: £85,275,643

Olympic Stadium

The pitch at London Stadium is the standard size required by Premier League and UEFA Rules, 105 x 68m.

Around this, an elliptical bowl made of several tiers is constructed to hold up to 80,000 spectators. In our illustration, this is mimicked by an elliptical ‘Donut’ inflatable, modelled after the second tier of the stadium which holds 55,000 seats, is 315 m (1,033 ft) long, 256 m (840 ft) wide, and 60 m (197 ft) high. The surface area and volume of a ‘Torus’ – essentially a donut shape, can be found using the following equations:

To get the radius we approximated, using the distance measuring tool on Google Maps.

Inner radius: 80

Outer radius: 100

Volume: (litres) =(πr2)(2πR)=(π·80×2)·(2·π·100)≈ 12,600,000

Surface Area: Surface Area = 4π2 Rr =  315,827m2

Man hrs: 9289

Cost Man Hrs: £139335

Number of blowers: 5760

Cost of blowers: £691200

Cost of electricity: £582,497,671

TOTAL COST: £584,117,774



Richmond Park


We have approximated the volume of a deer (don’t ask us how..) to be:

75x100x25cm (187,500cm3)

and a tree to be 25ft x 1.5ft  with an extra 15ftx10ftx10ft for the width of the foliage of one English Oak.

Deer : 630 x 0.1875 cubicM = 118.125 Volume

1.11484sqM surface area x 630 = 702 Sq. M

Trees : 170,000

V=πr2h (trunk .5 x 5) x 170,000 = 3.93M^3 x 170,000= 668,100 Volume

17.28m2 x 170,000 SA = 2,937,600 Surface Area

V=4/3πr^2h (Foliage 3.5r) x 170,000 = V≈179.59 x 170,000 = 30,530,300 Volume

153.94m2 SA x 170,000 = 26,169,800 Surface Area

Total : 31,198,518m3 Volume

Total : 29,108,102m2 Surface Area

917600 man hours * 15ph = £13764000

£72,770,255 in materials

14,262 Blowers * £120 = £1711440

£14,422,885 in energy costs / yr

Total:  £102,668,580




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