Subsidence: The Symptoms and the Causes

It’s every homeowner’s nightmare. The realisation that the very ground on which your home stands, is on the move.

The problem with subsidence is that by the time the symptoms are visible, the damage is already done.

There are some very early signs which many people miss including doors and windows beginning to ‘stick’ when they’re opened or closed. But other signs are more often the first to be spotted and they include cracks around door frames or windows and particularly around extensions where the newer building meets the older. This is due to the buildings trying to pull away from one another.

It should be noted that most buildings, especially older properties will have some visible cracks both within and without but cracks which are due to subsidence are often very distinctive in appearance and are usually quite small, diagonally situated and wider at the top than at the bottom.

Some of the main causes of subsidence include the following;

  • A long spell of dry, warm weather
  • Soil which contains a high quantity of clay
  • Large trees close to a building can suck out moisture from the areas around your foundations which causes them to shrink
  • A leaking drain which can soften the ground

Steps to Take to Avoid Subsidence

Of course we all want to avoid subsidence; it’s responsible for a lot of stress, paperwork and sometimes years of wrangles with insurance companies but there are some things you can do to help your property stay on the straight and narrow.
Check your drains and pipes on a regular basis to make sure there are no blockages or leaks. This is particularly important during and immediately after winter. Trees need to be pruned on a regular basis as this will reduce their water consumption and make sure that any new trees or shrubs are planted at a safe distance from the building.

Why is Concrete Bad for the Environment?

Concrete is still widely used in the building industry as a result of its strength. It’s typically utilised in the building of most construction types including houses, tunnels and public buildings.

Concrete and cement are often spoken of as though they were one and the same thing but cement is merely a part of concrete, a quantity of its whole together with sand, gravel and water. Cement is the binder within concrete and it’s what keeps the whole mixture together, lending strength and durability.

Because we can’t speak of concrete without discussing cement, we must therefore look at why cement is an issue for the environment.

Why Cement is the Issue

Second only to coal-powered electricity, the manufacture of cement is the largest emitter of greenhouse gasses and it accounts tor 5% of yearly anthropogenic global CO2 production.

For each tonne of cement produced, a tonne of CO2 is produced with it.

Why is CO2 Bad?

CO2 is a naturally occurring gas which is emitted by human activity. It’s one of a number of greenhouse gases within our atmosphere; others include water, vapour, ozone and nitrous oxide.

In order to begin to understand the impact of these gases, we have to begin with the sun. The sun sends solar radiation (light) to Earth and the atmosphere deflects a certain amount of this radiation; the rest hits the plant’s surface and warms the land and oceans.

The earth then radiates its own heat upwards in the form of infrared rays…some of which escape the atmosphere and some of which are absorbed and remitted by atmospheric gases…these gases are greenhouse gases and they help the planet to retain its usual temperature.

The natural systems of Earth regulated the production of greenhouse gases very successfully for millions of years. Gases were absorbed and emitted at healthy rates whilst temperatures were regulated at a good level which supported life on the planet.

Humankind managed to live in harmony with this regulated and perfect system until around 1750 – the start of the industrial revolution.

Since that time, we have been adding greenhouse gases, mostly CO2 to our atmosphere at a regularly increasing rate. We have been trapping the heat and as a result of that, causing temperatures to rise.

CO2 represents around 84% of all greenhouse gases for which humans are responsible and most of it is as a direct result of burning fossil fuels to provide electricity and transport but industrial processes contribute enormously.

With 25 billion tonnes of concrete produced globally on a yearly basis and around 900 million tonnes of construction and demolition waste (of which between 20% and 80% is made up of concrete) is produced in Europe, the U.S. and Japan alone, it makes sense to consider how much of its application is strictly necessary when there are innovative alternatives on the market.

Whilst the U.K. is the current global leader when it comes to recycling concrete (reusing 22% for aggregate in roads) there still needs to be a huge rethink in terms of the way in which concrete is produced, used and recycled.

How Can We Improve the Situation?

There are many theories which discuss a variety of strategies which could potentially improve the situation with regards to concrete; the production methods used, the mixes which are currently sold and the ingredients used have all been discussed and new ideas are emerging which could improve the outlook for the future of the planet.

Helical Piles as an Alternative to Poured Concrete Foundations

Helical piles require no concrete whatsoever and are currently the most practical and effective way to avoid the use of concrete within foundations. Cost-effective and fast to install they are suited for ground conditions at every individual site.

They may be installed;

  • At raked angles
  • Protruding from the ground or buried
  • In any soil
  • To support structure in compression and tension
  • At grade, on embankments and in cuttings
  • In low temperatures – unlike concrete
  • In bespoke situations

With so much at stake, it makes sense for the construction industry to embrace the newest and most innovative tools available – especially when they make financial sense.

Why are Helical Piles the Best Choice?

Helical Piles have so many benefits that once you understand them, it’s hard to see a reason not to choose them over traditional foundations. However, some people remain slightly sceptical of them. This comes from some lack of understanding for the most part as many people assume Helical Piles are a new idea or a new technology when in fact, the first Helical Piles were used over 200 years ago!

In the past, Helical Piles were usually put to good use on coastal structures such as lighthouses and piers where their firm grip was the best solution in the unstable marine environment, but recently, the advantages of them have seemed more relevant than ever and so people are choosing them over concrete foundations for buildings of all types and in all kinds of landscape.

Some of the main benefits of Helical Piles include the following:

  • Fast installation means less cost
  • No concrete means ecologically friendly and fast curing times
  • Small base construction means ease of installation even in restricted access areas
  • Removable and reusable
  • Lack of noise during installation means minimal disruption
  • Can be installed in any soil
  • Can be installed at an angle
  • Suitable for marine applications

The benefits of Helical Piles clearly outweigh traditional foundations when compared in many areas.

Not only is the cost less but the cost to the environment is much less.


Amazing Structures of the Past Still Standing Thanks to Helical Piles

Helical Piles aren’t a new concept; they’re gaining popularity fast thanks to their recognition as one of the most underrated engineering feats of the 19th century and as we learn more about the environment, we’ve naturally come to realise that Helical Piles are by far the kindest foundation solution when it comes to ecological awareness.

Because Helical Piles use less machinery, less manpower and no concrete, their impact on the environment is significantly less than that of traditional foundations.

They are also extremely effective…there are some very well-known landmarks which are still standing in the UK today thanks at least in part to their Helical Piles.

Many historically interesting coastal structures were completed using the then, innovative and brand new system including the famous Margate Pier which was in fact the very first pleasure pier to be built with Helical Piles.

Margate Pier was built in 1853 and designed by Eugenius Birch; it was his first pier and he used Helical Piles in its construction. It opened in 1855 and was also the first iron pier in the country. After numerous near misses over the ensuing years when the pier was almost lost to fire and weather, it was still standing during WWII when it was utilised for troop and supply movements.

It came to a sad end in 1978 in a severe storm but a small section of it remains to this day as a testament to the earliest efforts of the engineers who pioneered Helical Piles.

Gunfleet Lighthouse in Frinton-On-Sea Essex was built in 1850 by James Walker. The screw pile lighthouse is still standing, mounted on 7 piles and includes living accommodation.

It is now used as an automated weather station.

The Palace Pier in Brighton was opened in 1899 following a fraught few years in which progress had been blighted by storms. The Palace Pier was built to replace a much earlier pleasure pier which had been completed in 1822.

The new pier was heralded a triumph and included 330 screw piles to counter the shifting sands upon which it was built.

The pier was briefly up for sale in 2011 much to the dismay of the general public but was subsequently withdrawn from the market by its owners; it remains Britain’s most visited pier.

The UK’s coastal structures form a valuable part of our heritage; with so many beautiful and long-lasting period landmarks still standing thanks in part to Helical Piles, we can only hope that there are yet more, innovative and exciting heritage buildings yet to come.


Helical Piles the Future of Construction

Understanding when and where Helical Piles are the best solution in building is dependent on first understanding their purpose.

Any foundation needs to be strong enough to support and to bear the weight of whichever structure rests above it. When we look at traditional foundations we come to realise that they are inherently weak.

Varying soil conditions, water or plant life can all contribute to the detriment of a traditional foundation meaning that the building it supports can suffer damage. As moisture seeps into the fabric of the building, walls can crack or bow, floors can list and within the building, the weakness of the traditional foundation becomes all to apparent.

In some areas, flood prone areas in particular, it is vital that foundations are extremely stable or the risk of damage is high. Helical Piles are often the best solution to the problem of building in flood prone areas or in areas where the ground is unstable for other reasons.

Helical Piles are basically steel shafts with blades which are attached in a corkscrew fashion in the manner of a screw. This is sometimes simply referred to as a pile. Piles are attached to the foundation and screwed into the ground; the weight bearing ability of the structure is drastically increased and the structure is also stabilised.

The piles act as a means of spreading, or sharing the load of the building they’re supporting and they can also be added to buildings which have already been completed with traditional foundations in place but which may need stabilising due to subsidence or other damage.

Helical Piles could become mandatory in areas at risk of flooding and because of this they are the best option for any new construction and for any construction on unstable land.

Another great advantage of Helical Piles is the ease with which they may be installed in tight, difficult to access areas. The equipment used to install Helical Piles can be operated even in very awkward spots.

Eco-Friendly Foundations

Helical Piles are a low impact solution offering significantly reduced carbon emissions as well as fast installation with minimal noise pollution. Helical Piles are also removable and reusable…. unlike traditional foundations.


Because Helical Piles are available in a variety of lengths and thicknesses to suit different needs, they’re incredibly versatile and can be provided to suit your exact needs.

Not only can they be used in any soil, but they can also be used at varying grades and at varying angles; the pile is designed to fit the conditions at the site in question and installation is far cheaper and faster than that of traditional foundations.

The future of construction is already here and it’s a lot more reliable than it used to be.




5 Historical Uses for Helical Piles

Helical piles are a geotechnical engineering feat with a strong, varied history of use. Read on to find some examples which may surprise you.

Helical Piles Were First Used as River Moorings for Ships

The first documented use of helical piles was in 1836, in which their recorded function was as river moorings for ships. These river moorings (also called ‘pile moorings’) consisted of poles with wide blades spiraling around them which were literally screwed into the bottom of the waterway. A portion of the poles breeched the surface of the water. Ships and smaller marine vessels would then secure ropes to the tops of several of these moorings when docking.

Helical Piles Were Used to Protect the Banks of Rivers

Helical piles were used by Alfred Goodwyn in 1858 for the Corps of Royal Engineers of the British Army. At that time they were used to anchor brushwood, which protected the banks of rivers. The equipment used included 1 inch rods with 5 1/2 inch helixes and 1/8 inch plates that were 2 inches in pitch.

Helical Bridge Foundations Helped to Expand the British Empire

Throughout Africa and India, screw piles were used to support bridges, which helped to extend the reach of the British Empire. This engineering feat was subsequently utilised throughout the world. For example, according to the Engineering and Building Record, a screw pile supported bridge was installed over the Wumme River in Germany on the 5th of April, 1890.

Helical Piles Created Sturdy Walkways for Wetlands

Wetlands are by nature challenging soil conditions on which to anchor footpaths. However, these walkways are quite stable when helical piles are installed to support them. The use of concrete isn’t advocated here, as the concrete can leech contaminants into the water. Screw piles work by penetrating into the waterlogged soil until they reach a depth and soil strength that can maintain sufficient weight bearing capacity.

Helical Piles Helped Host Visitors During the 2012 Olympic Games

When the UK was entertaining several thousands of sports enthusiasts, Screwfast was there to help. We installed 20,000 bespoke foundations for seats in various Olympic event venues. Then we uninstalled and recycled them; an environmental victory for everyone.

Hopefully, you’ve discovered some new information about the use of helical piles. With such a varied history, this is one foundation solution that will continue contributing to society for generations to come.

For more information on our helical pile foundations, or about any of our foundation solutions, contact Screwfast today.

Helical Piles: Installing Art in a Grade II Listed Park

Grade II Listed Properties have distinct rules of engagement when it comes to planning permissions, which include aesthetic, practical and environmental considerations.


History and Brief by Southwark Council

ScrewFast received a brief by the local council to create foundations for two unusual pieces of art with unique history; caryatids (Greek sculpted female figures) that originally lined the entrance of Rotherhithe Town Hall in 1897.Rotherhtihe Caryatides Southwark-Park

The Rotherhithe Town Hall had the caryatids attached to the façade that lined the entrance of the building.  These pieces were created by international architecture sculptor Henry Poole, who also created art installations for St. Paul’s Cathedral and Westminster.

Rotherhithe Town Hall was later converted into a museum and library prior to being bombed in WWII.  The caryatids survived the Blitz and many years of standing among ruins.  They were then transferred to the Heygate Estate in Elephant and Castle.

The Caryatids: Searching for a Foundation Solution

The caryatids measure 2850mm (3550mm in height) with the stone plinth and are 670 or 1100mm in depth.  On the Heygate Estate, they were surrounded by large brick pillars, which were obstructive and detracted from the elegance of the caryatids.

Consideration was given during planning to the aesthetic impact of the statues, and how relevant they would be in the context of the Grade II Listed Park.  Helical piles were the natural solution.  They would support the weight of the sculptures without obstructing the parks’ aesthetics.  The supportive foundation of helical piles is underground.  Thus, the view and look of the park would be preserved.

Historical Implications for The Foundation Installation

As a Grade II Historic Listed Park, the town council was also keen to preserve the tree roots surrounding the location.  Helical piles would support the heavy statues while protecting the roots.  This met the local council’s key requirement, and satisfied planning permissions.

With helical piles, no concrete is required and the small base construction is perfect for use in restricted areas like this.  There is no concrete curing time needed, so installation is fast and efficient.

Installation supported open space use and maintained the spacious feel of the park. ScrewFast completed installation by hand excavating the pits where the foundations were to be installed.  The helical pile foundations were a perfect fit, and Southwark Park has never looked better.

For more information on helical piles or any of our foundation solutions, contact ScrewFast today.


Thank you to Gary Magold for the images.


Case Study: Pile Foundations for North London Extension

At ScrewFast Foundations, we often focus on the industrial applications that benefit from our piling systems. This includes the roads, rail, renewable energy and electrification, environmental and civil engineering industries. But screw piles have also been used successfully for years in domestic pile applications. Here’s one example of an architectural firm that implemented ScrewFast’s screw piles to solve the traditional challenges of building in an active period home.

Building Challenges For Foundation of A North London Victorian Home

Hampson Williams wanted to build a prefabricated rear extension on a North London Victorian home. The challenge was that the only access was a narrow front door (typical for period homes), which measured 826mm wide by 2,000mm high. All building equipment and materials would have to travel through this door. In addition to this, the home was being lived in throughout the project; any intrusion/disruption needed to be extremely limited. This ruled out bringing heavy equipment through the flat.

In addition to these challenges the local council had a ‘no skip policy’. Concrete and raft foundations would not suffice because large amounts of cement would have to be hauled through the building.  Furthermore, traditional concrete strip and raft foundations created substantial spoil. Finally, cement was rules out in order to create less of a negative environmental impact.

Solution:  ScrewFast Foundations Screw Piles


Why were screw piles chosen for this North London domestic application? Using Screw Fast screw piles provided the following benefits:

  • Less friction, disruption of the soil due to a narrower core tube
  • Less energy required
  • Lighter equipment was used (equipment fit through narrow front entrance)
  • Less noise which caused minimal disruption to household occupants
  • Fewer spoils were created than with cement (it was environmentally sustainable)

Foundation Development and Frame Installation

Sections of pile were bolted together and screwed in using a compact hydraulic rig. Six piles with a core diameter of 60mm were paired and installed manually using a tripod rig. Each pile was connected to a prefabricated steel plate pile cap. This was completed in a single day.

The steel frame was then constructed to support the roof elements and the timber floor. The joint locations and frame sections were carefully measured to fit through the narrow entranceway. The frame was bolted together and fully installed in just two days time. The end result was the rear extension of a beautiful Victorian mid-terrace flat in North London with a new kitchen and dining space.

ScrewFast Foundations can supply a variety pile foundations for every size project imaginable. We offer an innovative solution to your building challenges.

For more information on our screw piles or any of our foundation solutions, contact ScrewFast today.


Helical Pile Construction vs. Traditional Foundations

Helical Piles were first used almost 200 years ago and are generally credited to an Irish engineer Alexander Mitchell who discovered how effective they were in securing lighthouses and other structures around harbours where the ground is not stable.

Since then, technological advances have meant that the use of Helical Piles in construction has gathered pace and they’re used today in both tension and compression load applications. They are a versatile product and the installation equipment needed is minimal when compared to that needed for traditional foundations, because of this it is a far simpler process to install them in access-limited areas.

Another advantage to Helical Piles of course is that their installation is not weather-dependent; with traditional poured foundations there’s the need for not only clement weather, but also heavy equipment with a big workforce to operate it.

Because Helical Piles do not require any excavations with the ground only being disturbed minimally during their installation, there are no spoils to dispose of once the work is complete, which of course means that there is no risk of exposing contaminated soil and less cost is incurred generally. Unlike traditional foundations, Helical Piles require no curing meaning much time is saved.

Advantages of Helical Foundation Systems

  • All weather installation is possible
  • Installation in areas of limited access is possible due to the fact that they may be installed with hand-held equipment
  • No ground vibrations produced during installation
  • No need to dispose of spoils following installation
  • Simple to remove via reversal of installation process
  • No curing period needed so load tests may be immediately undertaken following installation
  • No concrete or grout needed minimising mess, waste and equipment on-site
  • Environmentally friendly; steel can be recycled unlike concrete

With the immediate advantage of speedy installation using small and basic equipment another evident plus is that of cost. When compared with traditional foundation methods, Helical Piles can cut expenditure by around 50%.

Helical Piles are the best choice in flood-prone areas due to their ability to remain stable and a speedy, waste-free installation process makes them a sensible choice for those who wish to save both time and money on their projects.

Helical Piles are the future of building as a less-invasive, more environmentally friendly and cheaper alternative to traditional foundations.

How to Spot An Amateur Pile Foundation Company

Foundation installation is continually evolving with new techniques, procedures and tools. When amateur pile foundation companies are hired, errors are made, budgets are stretched and safety is compromised. Here are five of the top indicators of an amateur pile foundation company.

Amateur Pile Foundation Companies Lack Experience

There is no substitute for experience in this field. ScrewFast has not only been working in a range of foundation industries for nearly 2 decades, but we maintain a training school to teach new installers and to provide refresher courses for experienced staff.

Amateur Pile Foundation Companies Lack Strong Safety Records

Amateur foundation companies have been known to cut corners. This can lead to injuries of staff, clients and even the general public. ScrewFast takes a different approach. Our vigilance to safety during all projects has paid off.

We’ve never had any serious injuries to anyone including those involved with the manufacture, installation, and use of our products. We also have a ‘no failure in service’ history and are backed by a number of consulting organisations around the world such as Mouchel, URS, Arup, WSP, Atkins, and Mott McDonald.

Amateur Piling Companies Treat All Terrain as Equal

Terrain varies considerably and so must one’s approach to installing foundations. It’s imperative to know the local ground criteria. Our piles are manufactured only after sound geotechnical assessment of soil particularities in order to meet ground conditions. This includes the addition of rock cutting teeth and profiled leading edges to helical piles for penetrating rocky terrain.

We have a specialised drill/hammer that enables us to install piles through frozen soil, solid rock and even reinforced concrete. Other soil types include installations in water (marine industry) and soft soils, which require an entirely different approach and different installation equipment.

Amateur Piling Companies Lack The Right Tools

The right equipment is essential in geotechnical engineering. This should be obvious. However, many vendors do not have the facilities or the equipment to properly test, predict and execute pile foundation projects.

Amateur Piling Companies Lack Geotechnical Knowledge

Knowledge is critical for safe screw piling execution. Too often, amateur piling companies do not provide enough training, certification or experience. Their staff lack the engineering knowledge they need to adequately perform installations safely and effectively.

ScrewFast is the largest and most experienced screw pile provider in the UK. We have a team of in-house engineers with advanced post-secondary training. This includes a number of disciplines such as Structural, Chartered Geotechnical and Mechanical Engineering.

Our knowledge base has enabled us to become a pioneer in the screw piling industry. For example, we’ve invented helical rock piles and larger helical piles for wind turbines as well as highway structures. We have a team of in-house engineers with advanced post-secondary training. We are ISO 9001-Certified by UKAS.

The truth is, an amateur screw piling company is easy to recognise. We hope this has given you an idea of what to steer clear of when you are searching for foundation professionals.

For more information about any of our foundation solutions, contact ScrewFast Foundations.

Balfour Beatty Associate Highways England Osbourne Associate Kier Associate