When were cavity walls introduced? Cavity wall construction history.
Cavity Wall Construction History
This overview of the history of cavity walls looks at how the use of cavity walls started. It also looks at some of the problems that property owners need to be aware of and how AWT can help to solve these issues. Read on to find out about:
- Development of Cavity Wall Construction
- Wall Tie Corrosion
- Wall Tie Life Expectancy
- Wall Tie Damage by Corrosion
- Modern Wall Ties
Development of Cavity Wall Construction
Cavity wall construction has almost entirely replaced solid wall construction in the United Kingdom. It evolved in the latter years of the nineteenth century and became common in dwellings in northern and western Britain in the early 1900s.
Its widespread adoption as virtually standard in the construction industry happened throughout the building booms of the 1920s, ‘30s and ‘40s.
The gallery above shows the typical outer leaf (the external brickwork) of a cavity wall and the type of damage often associated with failing cavity wall ties.
When identifying whether a wall is of solid or cavity construction, something to be aware of is that the presence of headers in the brickwork (bricks laid with the smallest side facing out) is not always indicative of solid brickwork.
From the mid-1940s to the mid-1950s, “snapped headers” were often used in cavity wall construction to emulate the English bond brickwork pattern that was common in solid brickwork.
Action Wall Ties can help identify whether your property has cavity walls or solid brickwork and diagnose the underlying cause of structural defects.
In the early years, the skins of these cavity walls were held together by metal ties made from cast or wrought iron, mild steel or copper.
Wall Tie Corrosion
The corrosion of wall ties was first officially recognised in the 1960s in South Wales. At first, it was thought to be due to a combination of poor tie protection and exposure to the elements. Time has shown that many of the early ties and mortars were just more susceptible to corrosion.
Mild steel ties initially were either left unprotected or given a bitumen coating, but in the early 1930s zinc coatings or galvanising became accepted.
The most common type of mild steel ties (under BS 1234) are strip ties (commonly known as vertical twist or fishtail) and wire ties (commonly known as butterfly or double triangle). The photo shows a range of traditional wall ties, all of which are prone to corrode and fail over time. In contrast, modern wall ties are carefully designed for strength and durability.
Wall Tie Life Expectancy
It is very difficult to predict the life expectancy of ties used in the construction of houses before 1945.
However, it can be fairly accurately predicted for those built between 1945 and 1964 :
- Strip ties will probably last somewhere between 31 and 61 years
- Wire ties will probably last somewhere between 15 and 31 years.
The expected life of ties used in construction between 1964 and 1981 is estimated at:
- 23 to 46 years for strip ties
- 13 to 26 years for wire ties.
ALL mild steel wall ties will eventually corrode – the only question is when!
As shown in the photo, Action Wall Ties can survey cavity wall ties by drilling small inspection holes and using an endoscopic camera to assess the wall ties. Contact us to arrange a wall tie survey.
Wall Tie Damage by Corrosion
The key here is catching the problem as early as possible. If the symptoms are recognised before deterioration has progressed too far, the walls may be re-stabilised rather than needing to be re-built.
Old ties must be located using an electronic detector and replaced with a suitable corrosion-resistant remedial fixing.
Finally, existing ties will need to be isolated to prevent further damage to the outer leaf of brickwork. Corrosion of a tie within the inner leaf of a cavity wall is unlikely to become significant as they are embedded in a dry environment.
AWT’s specialist equipment allows them to isolate failing wall ties and install remedial wall ties with minimal disruption by working from the outside of the building.
Ferrous oxide (rust) will result when embedded mild steel wall ties corrode. This will expand to several times the thickness of the metal it has resulted from, often breaking through the outer leaf of the brickwork (sometimes splitting the bed joints) and causing either lifting or bowing of the walls and damage to internal finishes.
From a structural perspective, this leaves the wall vulnerable to vertical and wind loads, especially in the case of large gable and unreturned walls. The instability of the wall will eventually result in the ties corroding away completely, necessitating the rebuilding of the wall. The gallery shows how corrosion causes the cavity wall ties to lose strength and eventually crumble away.
Modern Wall Ties
As shown below, Action Wall Ties uses a range of modern cavity wall ties that are far superior to traditional wall ties. Using their many years of experience, AWT selects the most appropriate remedial wall tie style for each project.
There are 3 main types of replacement wall ties:
- Resin or grout bonded
All AWT’s replacement wall ties are made from high-grade stainless steel. They are designed to restore structural integrity and provide a long lasting solution to cavity wall tie issues.
Equipment designed by AWT can also realign brickwork that is bulging and bowing due to failing wall ties before installing new wall ties and lateral restraints.
Kent based Action Wall Ties (AWT) are specialists in wall tie surveys and replacement, providing professional solutions to a wide variety of cavity wall problems. We serve domestic and commercial customers, local authorities, housing associations and insurance companies across London, Kent, Essex, Sussex and Surrey.
Contact us to discuss your requirements or book a survey on 01227 721 255, or email us.
Cavity Wall – Construction, Insulation, Problems
A Guide to Cavity Walls
If you are considering getting your property insulated, you have probably heard the term cavity wall. But what is it exactly, what purpose does it serve, and why should it be insulated?
What is a Cavity Wall?
A cavity wall is constructed with two separate walls that are used as a single wall. There is a space or cavity between the two walls. The two walls are known as the leaves of a cavity wall, with the outer wall known as the external leaf and the inner wall known as the internal leaf. Sometimes, the cavity wall is known as a hollow wall.
What is the Purpose of a Cavity Wall?
Cavity walls are used for a range of different purposes, including:
Cavity Wall Thermal Insulation:
The air that circulates in the wall cavity acts as a non-conductor of thermal heat. As a result, it minimises the transmission of heat from the external face of the interior leaf in the cavity wall. This significantly improves the thermal insulation in a building.
Cavity Wall Damp Prevention:
The cavity wall aids in the elimination of moisture penetration from the outer leaf to the inner leaf, helping to keep the inside of the building free from damp problems. This is possible due to the fact that any moisture that penetrates through the outer leaf will be evaporated by the air inside of the cavity when it is kept well-ventilated.
Since the cavity prevents dampness from penetrating the wall, the inner wall of the cavity, which is always a load-bearing wall, has a significantly reduced risk of efflorescence.
The air inside the cavity wall will act as a cushion that absorbs sound. Buildings with cavity walls are more soundproof compared to those without, with considerable external noise absorbed in the cavity.
In construction, cavity walls are found to cost around 20% less compared to a solid wall of the same thickness.
Cavity Wall Detail: Size and Construction:
The cavity between the inner and outer leaf should be no less than 50mm and no more than 75mm. The cavity may be either ventilated or sealed. A ventilated cavity is more effective for preventing damp, while sealed cavities are more effective for providing thermal insulation in the building. Ventilation of the cavity is achieved using air bricks in the outer leaf at the top and bottom of the cavity.
Since the cavity below a damp proof course does not serve any purpose at this the level of the foundation concrete block, the brickwork in the foundation will typically be constructed as a solid wall, and the cavity wall is started at ground level. This helps to draw out any condensed moisture below this level.
Cavity Wall Construction Details:
The cavity walls have an inner and outer leaf, with a hollow space in between them which is known as the cavity. The cavity width generally varies from 50-75mm. The outer leaf of the wall is usually a non-load-bearing wall and is half-brick. However, the inner leaf is typically always load-bearing and should be no less than one brick in thickness.
Bonded bricks or wall ties are used to connect the two parts of the wall. When metal wall ties are used, they should be spaced at horizontal intervals or around 0.90mm, and at vertical intervals of around 450mm. Wall ties should be arranged in a staggered fashion.
Cavity Brick Wall History:
Cavity walls became a common feature for external walls of almost all small buildings between 1920-1940. They were also common in Greek and Roman times but were developed in the 18th and 19th centuries as a component of contemporary construction. However, even during this time, the construction of cavity walls was rare and when it was used, would generally involve two masonry leaves that were bonded by headers spanning the cavity. The use of metal wall ties to connect the two leaves was only introduced in the second half of the 19th century, and the trend became more common at the beginning of the 20th century.
Cavity Wall Advantages:
Cavity walls are often used in construction because they have many advantages. These include:
- No direct contact between the inner and outer leaf except for at the wall ties means that there is a very low possibility of moisture being able to penetrate from the outer leaf to the inner leaf. Well-constructed cavity walls can withstand heavy rain while preventing moisture from reaching the inner wall surface.
- The air in the cavity is a non-conductor of heat, which reduces the transmission of heat from the external to the internal face. Because of this, cavity walls are the ideal option for temperate control in rooms in hot climates.
- Cavity walls offer good sound insulation. A 225mm cavity wall will have a higher sound insulation value compared to a standard thick brick wall, significantly reducing the effect of external sound.
- Cavity walls can reduce the risk of moisture condensation, they are fire-resistant, and offer protection against efflorescence.
Cavity Wall Disadvantages:
Although cavity walls are commonly recommended in construction for their benefits, they do have some disadvantages to consider. These include:
- The construction of a cavity wall requires expert supervision.
- A vertical damp-proof course to all openings is required
- Expert designers and highly-skilled tradespeople are the basic requirements for the construction of a well-built cavity wall, therefore, they are often more expensive to construct compared to a solid wall.
- Regardless of the insulation material used, there is always some level of risk that the moisture will be able to penetrate inside and lead to damp.
- The saturation and settlement of insulation materials used to fill the cavity wall can lead to thermal-bridging, which is when heat moves across an object that is more conductive compared to other materials around it.
- There is the risk that cavity wall insulation may leave unfilled air pockets, which can lead to cold spots that attract condensation on the inner walls.
- Cavity insulation will make the outer leaf colder and therefore wetter. This can lead to rusting of the wall ties being sped up. If the wall ties must be replaced, there is no satisfactory way to refill holes further in the insulation regardless of the insulation material used.
- Many buildings have mortar droppings on the wall ties within the cavity, which can result in penetrating moisture and dampness.
- The insulation thickness is restricted based on the cavity width.
What is Cavity Brick Wall Insulation?
Cavity walls are often filled with various materials to provide greater thermal insulation to the property. There are several materials that can be used, and the most common include:
Rockwool or Mineral Wool:
This is the type of insulation that is most commonly used to insulate the cavity wall in residential buildings. It is made from igneous rick that is heated and spun to create a fibre material. It is then blown into the cavity wall, where it occupies the cavity space between the inner and outer leaf. Rockwool is a water-resistant material and can prevent moisture intrusion from rain, which will usually leak through the wall’s outer leaf to reach the inside leaf.
Cavity Foam Insulation:
Urea-formaldehyde foam was commonly used to insulate cavity walls; however, it is becoming a less popular option. The insulation material can be added via small holes that are drilled into the walls or the brickwork and can be used as both insulation for the cavity wall and a stabilisation material for wall structures where the wall tiles have been futile.
Expanded polystyrene beads, also known as EPS beads, can be used to insulate cavity walls. They are pushed into the cavity of the wall and mixed with an adhesive to ensure that the beads hold together and avoid the risk of spilling outside of the wall. This type of insulation is usually a popular option for narrower cavity walls, where it is easier to use compared to Rockwool insulation. It is also a preferred option for some stone-built houses.
Cavity Wall Insulation Problems:
Cavity wall insulation that has been installed poorly can lead to problems, with damp being among the most common. Some cavity wall insulation has led to expensive repair work, especially in buildings where cavity wall insulation should have never been installed in the first place, including attempts to add cavity wall insulation to solid brick walls, and poorly filled cavities that result in cold spots and internal condensation in the home. In some cases, cavity wall insulation might block the ventilation bricks in rooms such as the bathroom, which can lead to condensation problems. When the cavity is bridged by insulation, it may also allow moisture to penetrate from the outer leaf to the inner leaf, which can lead to internal dampness.
The construction of a cavity wall is a common way to control moisture and dampness in a home, along with providing sound insulation and thermal insulation benefits. Cavity walls can be filled with insulation material for further benefits.
Construction of the UK’s best railway 2022-2023
Good morning everyone and welcome to the repair
Siemens factory here in Hornsey, North London.
The train you see behind me is Desiro
Class 700, one of the most modern trains with digital
technologies in the world. Advantages
for passengers, including up-to-date travel information,
intelligent air conditioning and capacity 21
double-decker bus, have already changed the travel line
But the smartest technology is invisible to
passengers. Because it’s the first
a mainline train that can independently pass through
central London under the supervision of the driver and detect malfunctions
before they need to be eliminated by constantly sending
operational data to the Siemens control center.
Armed with this knowledge of how everyone works
train, the ultimate goal is to make the park trouble-free,
completely reliable, easy to maintain and with an unparalleled
control for the operator to meet the needs
So this is the right background for our today’s
discussions about how this industry should keep pace with
In a speech on the overhaul of iron
roads 12 months ago, which followed the publication
the Williams-Shaps plan,
I reflected on the historical events that shaped our iron
As a state-controlled railway
halved. How after
privatization in the 1990s, despite a doubling of passenger traffic,
industry has become more fragmented, complex and
unaccountable. And how are these problems
resulted in a disastrous schedule introduction in May 2018. Signs
were visible to everyone. swiftly
rising costs and delays in modernization, collapse of the franchise, poor
customer service and tardiness, crowded
Despite the obvious need for new solutions
to promote the railroad when I became transport minister
next year, it was obvious to me that much of the debate
about the future of the industry is rooted in worn out and outdated concepts
property. stuck in the past
only the railway, but also a conversation about how it
That’s why, after an exhaustive and thorough check
under the direction of Keith Williams, during which he closely
interacted with railway unions, our plans
reforms introduced a new vision.
Creation of a new
to put passengers and punctuality first,
bringing together the disparate parts of the industry, using common sense reforms
meaning to unravel the complexities and build a modern,
sustainable railway in line with the changing
First of all, the plans demonstrated our profound
faith in the future of the railway as the basis of British transport
systems. They were a vote of confidence in
industry and its workforce.
However, today we are here, railway
is just starting to recover from the pandemic and we are on
the brink of a nationwide strike.
These strikes are not only an attempt to disrupt
reforms that are critical to the future of the network and
designed to inflict damage at the most inopportune moment, but also
unbelievable act of self-mutilation by a trade union
Make no mistake, unlike the last 25 years,
when the growing demand for passenger transportation year after year
was taken for granted by the industry, today the railway
is in a state of struggle.
It is not only competition with other species
public and private transport, but also the fight against Zoom, Teams and
remote work. If unions are not
notice the world has changed.
Many passengers who did not have 3 years ago
alternatives to the train, today they have the opportunity not to
drive. Wave goodbye to them and
it will jeopardize the work of thousands
The last thing the railroad has to do now is
is to repel passengers and cargo customers by prolonged and
Trade unions allege that these strikes are related to
freezing wages. This
wrong, we are not introducing a wage freeze now that COVID
left in the past.
So, I tell the workers, your union bosses are under
false pretext put you on the brink of national
strikes. And instead of
protect your jobs, they actually threaten your workers
COVID left the railway in critical
financial position. Iron
the road lost a fifth of its passengers, lost a fifth
your income. Often these are the most
highly paid passengers.
RMT chief Mick Lynch recently told Sky News,
that “last year the railroads made a profit of 500
million pounds sterling.” This
denial of reality.
In fact, the operation of railways costs more than
£20 billion per annum and for the year to April 2021
they raised just £4bn through fees for
travel and other income.
Since the beginning of the pandemic, the government has allocated 16
billion pounds for emergency support
taxpayers for railways, £16bn
sterling to keep trains running and ensure that
so that none of the companies working under contract with
trains (TOC) operating on
contract with Network Rail
or DfT , was not
To be clear, £16 billion –
this is almost the same as our annual police budget in England and
Wales, just to support the railway during
pandemics. No railroad
lost his job. No one
person. In fact
the taxpayer couldn’t do more to support
Now that we are recovering and people are again
begin to travel, the industry needs to increase revenues,
attract passengers and implement the reforms needed to
For example, weekend trips are
huge growth area right
Now. But on most of the iron
roads under the agreement of 1919 work on Sundays is
In 2018, England played a World Cup match
football on Sunday. In that day
due to the fact that we could not get people to work, only
one operator had 170 cancellations.
Here’s another one
example. Currently only 1
out of 8 tickets sold over the counter but we still have
about the same number of cash registers as on the days when we all
stood in line at the stations to buy our
tickets. Quietest office sold
only 17 tickets for 3 months. This
one ticket every 5 and a half days.
Any reasonable plan would move staff to where they are
not needed, for example, at ticket offices, and will increase the number of shifts
where they are needed, e.g. on weekends
But then any reasonable plan would not include
punching yourself at a certain moment when your customers
returning after the national
crisis. Other industries are on the move
with time. So why not
I want to formally declare that we want to conclude
a fair deal including a pay rise
railway personnel. Whole
the point of these reforms is to build a sustainable, growing
railway, where every railway worker receives a decent
annual salary increase. But
right now, pay has to keep pace with the broader
the public sector.
Let me say it
differently. average salary
railway workers is £44,000, and the average
Train drivers’ wages are £59,000
sterling, with a fifth of drivers earning more than 70
000 pounds sterling. But average
a nurse earns around £31,000
Thus, an increase in wages by
rail transport can only be afforded in
long term along with
reform. This is true because
we are coming out of a pandemic. Fair
for taxpayers and fair to other government
We do not ask the railway workers to take over all
responsibility. We are cutting back
the number of senior managers and their salaries.
In fact, I constantly challenged high
salaries of senior employees of the railway network, and for the last
10 years they fell by 10% in absolute
expression. Executive Director
Network Rail is paid more than a quarter less than his
I can’t stress enough we believe passionately
that the reformed railway has light
future. We want the iron
the road remained a natural choice for people who need
fast and reliable travel between our main
cities. However, for this we
need to cut costs.
We work with industry, for example
rolling stock companies to increase
efficiency. It includes
maintenance methods that need upgrading,
and more efficient use of technology.
But the whole railway must play its part
role. Even before the pandemic, everyone saw
that the finances of the railroad
insolvent. COVID only
exacerbated the need for
survival. But I don’t just want
for the railroad to survive, we want it to
That’s why for the next 3 years we want
spend 35 billion pounds on support and development
networks. We want to expand the map
railways so that trains return to places excluded from
timetables after Beeching’s cut, with new stations from
Northumberland to Devon, with electrification to get rid of
slow and dirty diesels.
And we have made good progress: over 1200 miles
electrified under this government compared to 63 miles,
electrified for 13 years of government
Blair/Brown. And with HS2, the biggest
construction project in Europe, Northern Powerhouse Rail and
beautiful new line of Elizabeth.
In fact, we spend a total of 96
billion pounds for railroad overhaul
across the North and Midlands.
Great British Railways will provide a strong unified
industry leadership by bringing property rights under one roof
on infrastructure, tariffs, schedules and
net. Broken franchise system
replaced by new service contracts
revitalize the competitive market and improve quality
And we continue to upgrade rates and sales
tickets, introducing flexible tickets for hybrid operation and implementing
contactless pay as you go nationwide
about 900 stations.
New technologies replace old ones,
centuries old. For example, we replace
Victorian signaling by digital systems, which means that
we can place more on the line
trains. As the caterpillars
are used more intensively, maintenance becomes
even more important.
New ones help here too
technologies. The best way to check
way to detect defects – install sensors on
trains. Each of them makes 70,000
pictures per minute, finding tiny defects in the track that are not
can be seen by the human eye.
But unions still want this job
carried out today in the same way as it was done in the age of steam,
sending people to walk on rails and look at
rails. This not only reduces
the likelihood of detecting errors before they become dangerous, but also
more dangerous for personnel. And, to
Unfortunately, in recent years there have been several
deaths. We have to
Future response to
Without reform, all these investments and more
will be under threat. Many
The railroad workers did an excellent job during
COVID. Now they are used
trade unions for political purposes.
That’s why, if this dispute cannot be resolved,
the government will consider a full range of options to stop
unions that are detrimental to the general public, including the abolition of
a ban on the transfer of employees to replace the strikers.
And passengers will be compensated for
breakdown. In addition to existing
reimbursement agreements, we ensure that the owners of seasonal
season tickets will be able to claim full compensation for the days
So let me conclude by reassuring the trade unions
that we will not be distracted from the railway reform, from the creation
a more flexible and flexible workforce and from prioritizing rail
Just like we can’t upgrade
railroad with outdated technology, we cannot
do it by clinging to outdated ways of working from
of the past. Here we have a rare
the opportunity to fix problems that have long plagued the iron
But with strikes, all we’re going to do is
is to lose even more passengers, to lose even more revenue,
make further investment in the railway unprofitable and
potentially lose thousands of railroad jobs
This action not only has no justification, it is also
will cause suffering. misfortune for
people who have been looking forward to their first
Glastonbury. Trouble for the workers
who cannot reach their
work. Misfortune for students
who cannot take the GCSE and
A level. And woe to the people who are waiting
inpatient treatment, who can now skip
And there is another group of people that I
I’m worried. The railroad workers themselves
their families. They will be damaged by this.
blow. It doesn’t look like the old ones
times when RMT could bring the economy to a halt
Many railway users can now
work from home. For millions
passengers, the railway became a choice, not
necessity. Everything that gets in the way
people to choose the railway, everything that repels even more
passengers than we’ve already lost, should be bad news for
jobs and services.
So today I am speaking directly to
railroad workers, who, it seems to me, are less militant than
their union leaders. Don’t risk
strike your industry out of
future. Don’t risk losing
work. Don’t oppose yourself
Let’s correct this situation and return to
building a better railroad.
25 years ago the Eurotunnel under the English Channel was opened
25 years ago the railway tunnel under the English Channel was opened. François Mitterrand and Elizabeth II were the first to travel by train between France and Great Britain. Passenger communication under the ground could connect the island with continental Europe for about 200 years before that, but the British authorities consistently slowed down the project, fearing a military invasion. For this imaginary, as he believed, the threat of politicians was mercilessly criticized by the writer Arthur Conan Doyle, who dreamed of building a tunnel.
On May 6, 1994, Queen Elizabeth II of Great Britain and French President François Mitterrand inaugurated the Eurotunnel, a 50,450 m long railway tunnel, of which 39 km were laid under the bottom of the English Channel. The construction of a unique transport artery that connected Britain with continental Europe took seven years. 13 thousand workers and engineers were involved in the construction of the facility. Eurotunnel is the longest underwater and international tunnel. The American Society of Civil Engineers considers the site one of the modern wonders of the world. This organization has included the Eurotunnel among the 10 most significant building structures of the century as the best rail transport link.
The need for an alternative to maritime communication between the powers first arose about 200 years before the practical implementation of the project, when passenger, goods and other transportation reached serious volumes.
In 1802, the French engineer Albert Mathieu-Favier was one of the first to build a tunnel under the strait.
He proposed lighting up the underground arm with oil lamps and launching horse-drawn carriages along it. The project was approved by Napoleon, who suggested that the British immediately begin earthworks. Overambitious for those times, the idea was thwarted by the beginning of the War of the Third Coalition.
In the middle of the 19th century, the French repeatedly returned to the idea of building a tunnel. However, the British looked at such a prospect with great doubt, fearing the threat of an invasion of their island underground. Financial difficulties became another barrier each time. The first practical steps towards the implementation of the “project of the century” were taken only in 1881, when geologists carried out the necessary surveys and drilling machines began to dig a tunnel from two sides.
However, two years later the work was stopped. The British managed to dig 2026 meters by this time, the French – 1829.
And no matter how eager the engineers of both countries were to realize their professional skills and make a real breakthrough in the field of tunneling, the British government thwarted their ambitious plans by declaring the tunnel “undermining under the safety of the island.” The events of the First World War allowed official London to believe that they were right.
One of the staunch supporters of the tunnel was the famous writer Arthur Conan Doyle. In his open letter entitled “On the project for the construction of a tunnel under the strait”, published on 19In 16, in one of the newspapers, the “father” of Sherlock Holmes severely criticized the opponents of the project and stated the need to keep up with the times, including in terms of technology.
“They say peoples have to pay for sins, but stupidity costs them more. We, too, deserve retribution, because we foolishly abandoned an obviously winning enterprise, allowing ourselves to be intimidated by the ridiculous threat of an enemy invasion through a 26-mile-long rabbit hole. Truly, the stupidity of the people has found here its highest limit. Since the day when the likelihood of war with Germany had increased, I sent three different appeals – to the War Department, to the Admiralty and to the Council of National Defense – in which I proved the great importance of having such a tunnel for the defense of the state.
Having predicted the threat from submarines, I also showed how I would eliminate her tunnel.
I argued that since our communication lines would not be afraid of bad weather from now on, a significant part of the fleet (not to mention the escort ships) could be freed for other tasks. Our current tonnage deficit is largely due to the fact that we failed to do this. I do not know how many tens of millions of pounds would have been saved if any of the three institutions mentioned had met my arguments with sympathy. After all, we had the opportunity to build a tunnel before the start of the war. Now that it has become clear that a single wave of poison gas launched into the tunnel would destroy an entire enemy army there, it remains to be hoped that the ridiculous horrors with which they frightened us will die off by themselves, and at the end of hostilities, common sense in resolving this issue will finally it will triumph.”
However, the supporters of the tunnel did not give up. Until 1945, they proposed about 300 new projects for connecting the two banks. Among them were not only underground tunnels, but also bridges, and combinations of bridges with a tunnel. So, in 1922, drilling equipment started working near the strait again. However, even then politics intervened. Further 128 meters another attempt did not go.
It was only after the Second World War that the island became convinced that the military threat from the continent no longer existed.
In 1963, Britain and France announced that they had reached an agreement in principle to build a tunnel under the English Channel.
The start of work was delayed for a long time. The voices of skeptics still had sufficient weight, frightening them with terrible accidents underground and other dangers. Only in 1986 did the signing of a document on the joint implementation of the project take place. It provided for laying in the Cretaceous geological layer – quite easy to penetrate and at the same time waterproof rock at a depth of 40 m below the bottom of the strait. It was decided to connect the city of Calais on the French side and Foxton on the British side with a tunnel. Dover, which for many centuries was moored by ships from France, remained aloof from the new transport artery.
The historic treaty was solemnly ratified by British Prime Minister Margaret Thatcher and French President Mitterrand.
His arrival in Cantersbury, by the way, was accompanied by protests with egg-throwing and the slogans “Frog, go home!”
The British began laying on their territory on December 15, 1987, having previously calculated the trajectory using satellite observatories. The French started drilling 2.5 months later, because the layer of blue chalk in their area of responsibility went sharply into the depths. At the same time, up to 11 machines with a length of 250-300 m and a mass of 1-2.5 tons were engaged in digging. Each was serviced by a team of 40 specialists. On the French side, where quicksand had to be dealt with, the vehicles were pressurized like submarines. In the head part there was a rotating disk with a diameter of 8 m and a rotation speed of 2-3 rpm. Tungsten cutters crushed the rock.
The bucket loaded it onto a conveyor, which sent the destroyed soil to a freight train – and it was already transporting the material to the surface.
In total, over 8 million m³ of soil was excavated from the English Channel. The French mixed their part of the land with water and poured it into the sea, and the British formed an artificial Shakespeare Cape with an area of 0.36 km² from the exported soil, on which they later arranged a park.
Depending on the conditions, tunneling machines moved at a speed of up to 300 m per week. Every 1.5 m, the walls of the tunnel were reinforced with high-strength reinforced concrete segments. Six fragments made up a single ring.
On December 1, 1990, British builders Graham Fagg and Frenchman Philippe Cosette met at a predetermined point at a depth of 40 m under the English Channel floor, 22.3 km from Great Britain and 15.6 km from France.
The British and French made the last meters of the tunnel by hand with picks and shovels.
The Eurotunnel consists of three tunnels – two main tunnels with tracks for north and south trains, and one small service tunnel. The distance between them is 30 m. The service tunnel every 375 m has passages connecting it with the main ones. Every 250 m, both main tunnels are interconnected by a ventilation system located on top of the service tunnel. This airlock system negates the piston effect created by moving trains by distributing airflow into the adjacent tunnel.