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Prefab Homes on the Rise in the UK

Sometimes known as manufactured homes, what older generations in the UK will call Prefabricated homes are on the rise in the UK.

The old prefabs of post war Britain are mostly long gone, though a few remain as monuments to a simpler time. Built as temporary answers to a housing problem after the war when so many properties had been destroyed, the old prefabs provided much-loved homes for many families and some stayed in theirs for the rest of their life.

Now as some of the UK’s larger cities struggle to provide enough affordable homes for people with low-incomes and the retired, it seems that prefabs have once again come to the fore.

Modular developments in Manchester and in Liverpool are gaining traction thanks to a renewed interest in the low-cost, low-impact and affordable homes. Both cities are and have been for some time, dealing with extreme housing crisis and changes are afoot. A growing number of companies are looking into or are already, manufacturing prefab houses to fill the gap in availability.

The lack of affordable homes for young professionals and for older people stuck in the rental trap has needed addressing for some time and it has been estimated that prefab homes can be built in around half the time of a traditional new-build of bricks and mortar.

The homes are factory-built and whilst they are under construction, foundations are already laid or helical piles are used ensuring fast installation with minimum upheaval and mess. Once the would-be owners have decided to purchase a home, the order for it can be placed and building can begin.

The lack of mess and noise is of course an especially important consideration when prefab homes are being built to order and may be on sites with relatively small areas allotted per home. Some allotments will already be occupied whilst others are being installed, the lack of disruption which helical piles introduce is far preferable to traditional foundation digging which is not only noisy, long winded and dangerous but also expensive. Prefab homes are also touted as a more energy efficient option by dint of being smaller and utilising less concrete.

As the UK’s housing crisis shows few signs of abating, there are certainly many points of interest to consider with regard to prefab housing. Whilst smaller properties might not be suited to larger, or young families, with careful design, larger family homes could be constructed making new and vibrant communities for the future.

Soil Types and How They Affect Buildings

Soil varies enormously depending on geographical position. Country by country and county by county, soil types are different and even in areas where the soil is quite uniform there are always anomalies…spots where the ground is particularly chalky or unstable.

All buildings need a strong foundation or the structure simply won’t last. Unstable ground makes for unstable buildings. The strength and stability of any soil will depend on its properties. Clay-based soil is often very stable when compared to sandy soils but the best is soil with a mixture…gravelly type soils in other words. They have the best stability because of the relative firmness when compared to dry sandy soil which will always shift or moist soil which is prone to flooding.

 

Types of soil

Peat: This soil is often quite dark in colour and it can hold a lot of water making it easy to compress. But it also dries out very quickly and is also very combustible. It’s not ideal for building on.

Clay: Clay is excellent at storing water due to it’s makeup; it’s formed of a great many very small particles but because of this it shrinks and expands at a rate which makes it unreliable. An unstable soil like this means it’s not a good soil for building on.

Silt: Silt feels smooth and holds water for a long time but drains poorly and this means it expands quickly in damp conditions. Again, not ideal for a building’s foundations.

Sand/Gravel: Dry and gravely to touch it drains well and also compacts fairly easily managing to retain stability even in damp conditions. The only issue with this is that if the area is one with high rainfall, smaller gravel particles can be washed away meaning that the ground is left with gaps and spaces.

Loam: Loam is an excellent soil type for building on because it’s a combination of clay, silt and sand. It’s soft and crumbles easily when touched but when compressed is stable and secure.

Helical piles can overcome the difficulties faced when building on softer or unstable ground and even in high water tables. The piles are treated to withstand high moisture beneath the ground and this prolongs their life and depth can also vary, meaning that if the ground is more hospitable deeper, then that can be taken advantage of. With helical piles, there’s no need to be concerned about soil type, meaning that buildings are more stable and of course longer lasting.

Helical Piles for Boardwalks

Boardwalks are an important feature in wildlife sanctuaries and in protected wetland areas where sensitive wildlife needs to be protected. The minimum disturbance is preferable when allowing pedestrians into the area to observe and enjoy the landscape.

Usually elevated to allow for the ground beneath to be undisturbed, elevated boardwalks are an important feature in many places of environmental interest all over the world. Various methods are utilised in the building of elevated boardwalk foundations. Water presence is of course, an issue and excavating into wet ground is tricky due to foundation flooding. Therefore, helical piles are preferable in this situation.

A helical pile or screw pile is a foundation system which utilises steel shafts with plates welded up the length at strategic points. This anchoring system is also used in many other tricky applications, including power lines and wind turbines as well as lighthouses, buildings and street lights. The depth at which piles may be installed is considerable and additional lengths of steel may be attached as the need for more depth arises.

 

Why Helical Piles Are the Best Option for Boardwalks?

Wetlands are quite often protected zones. They are sensitive in an environmental sense due to the presence of wildlife and possibly endangered species. Because helical piles do not require any preservative and are chemical-free, this is a far safer option.

The installation of helical piles is also much faster, quieter and cleaner than traditional foundation installation; there is less vibration and noise and therefore less chance of disturbing the wildlife in the area. Because helical piles do not rot and are made of galvanised steel, their lifespan is far greater than traditional foundation systems.

Sinking Foundations

Sinking foundations are caused mainly by unstable ground and are a big problem for the owner of any building. The signs of a sinking foundation are quite obvious once you know what to look for. A sideways slant to a building is one of the most obvious warnings that all is not well beneath the ground but there are some other, less noticeable clues that your foundation is having a struggle.

Tell-tale signs include windows and doors which won’t close properly or simply “look off”. Cracks in basements or on walls in the main living parts of a home or business. Puddles of rainwater which gather around the base of a building are another symptom that something is amiss.

Once the damage begins to take its toll, that has an unfortunate knock-on effect and the buildings’ structure begins to gradually deteriorate, worsening over time with yet more features of the building beginning to suffer the effects of the shifting structure and that of the elements as they begin to gain entry into the fabric of the building.

If you know that your building is in an area with unstable soil, then it is even more important that you keep an eye out for the signs. Neighbouring buildings for example, may begin to show signs of damage before your building does…take this as a chance to rectify a problem which might be lying in wait. Sort it out early before anything actually happens.

Repairs to a sinking foundation can’t be carried out without a detailed analysis first to ascertain the problem. It’s not always necessary to take action right away…but it’s always best to make sure that this is the case before deciding not to worry just yet!

A structural engineer is able to survey the building and work out what the problem is. Then it’s time to decide what the solution might be. There are many ways to approach the issue of sinking foundations depending on the building and what ground it is built on.

High pressure grouting is one option and is usually used in domestic applications or for smaller buildings; it involves the injection of grout into the soil to improve its load-bearing capabilities. This technique is only effective for a certain amount of time though and is not generally seen as a permanent solution.

Helical piles are the longest-lasting and most reliable fix for the issue of a sinking foundation and because the installation of helical piles is quick and easy when compared to other building maintenance techniques, it is the option many building owners choose.

Eco-friendly, fast and cost-efficient, helical piles can be used in almost all circumstances…even on structures which are built on a slope or in very damp areas.

Helical Piles in Architectural Preservation

Helical piles have been slowly but surely coming to note across the globe as people begin to realise how broad they can be in their application. Not only are helical piles the best choice for building on unstable ground, they’re also cost-effective and ecologically friendly and in recent years they’ve been proving themselves valuable in terms of the conservation of heritage sites.

The use of screw piles for the restoration of historic buildings has many advantages. One of the main concerns for teams involved in restoring heritage sites is that of preserving the historic fabric of the site, even that which is not visible. Another concern is minimising disruption or damage to any remaining structure and installing screw piles is one of the least invasive techniques for in particular, underpinning a building.

The lack of vibration is also an important consideration during restoration of particularly ancient or sensitive structures as even the slightest movement of an older building can cause massive internal or external damage.

One U.S. building was reconstructed with the help of helical piles and is now an important site for visitors and historians alike. On the Eastern shore of the Rappahannock River in Stafford County USA, the remains of the childhood home of George Washington, the very first president of the USA were slowly crumbling. Little remained of the 1720’s-built house and experts had accepted its loss. But with research and hard work, a team of archaeologists and engineers have rebuilt the house with the help of helical piles. The house was built in the exact spot it had once stood and by using helical piles, the building team did not need to excavate the historical remnants beneath. They wanted to leave the site as untouched as possible and helical piles anchored the building without any destruction.

In the UK, Forest Lodge, the beautiful gatehouse at the historically important Hulne Park estate was saved from a certain collapse with the use of helical piles which were installed in the west wing of the structure and put a stop to the settlement which had been gradually getting worse over the course of many years. Hulne Park is home to gardens which were designed by Capability Brown and also an ancient priory. The gatehouse was and is an important feature of the estate having been built in the mid-nineteenth century and served since then as a suitably grand entrance to a special place.

Helical piles offer a valuable contribution to the preservation of many important historical buildings and in the future, we can expect to see their use increase as more valuable buildings begin to show the marks of time.

10 Interesting Facts About Helical Piles

Unless you work in the industry or have had reason to do your research, it’s unlikely that you know much about helical piles. We’ve put together 10 interesting facts for you, which will hopefully answer any questions you may have, but if you have any more, please don’t hesitate to get in touch.

  1. Helical piles are a type of building foundation, consisting of a steel shaft with steel plates welded together at strategic positions. They are designed to hold the weight of whatever structure they are supporting.

 

  1. Invented by Alexander Mitchell nearly 200 years ago, helical piles are becoming increasingly more popular in the construction industry. They anchor a structure to the ground, unlike concrete which merely glues it into place.

 

  1. Surprisingly, Mitchell was blind. He won the Telford Medal for his invention, three years before the first helical piles were put to use in mooring ships.

 

  1. In fact, helical piles were initially limited to nautical use, including Maplin Sands Lighthouse and Brighton Pier.

 

  1. When compared to concrete, helical piles have a variety of advantages, including speedy installation and easy removal.

 

  1. Helical piles are suitable for a variety of applications including ordinary houses, street lights, tower blocks, roads and railways.

 

  1. Recent experiments suggest that helical piles are a fantastic choice in earthquake prone areas.

 

  1. As well as earthquakes, helical piles are also designed to withstand high levels of moisture beneath the ground. The lack of noise and disruption is also a bonus, particularly in residential areas where noise needs to be kept to a minimum.

 

  1. Essentially, helical piles can be installed in any location, no matter what the climate; even if the temperature drops to below zero.

 

  1. Since they are made with metal, helical piles can be recycled time and time again, making them a lot more environmentally friendly than concrete.

Helical Piles in Extreme Weather

Helical piles have been around for many years, but they are yet to reach their full capacity as the excellent, ground-breaking examples of engineering that they are. They are used in many environments, including houses, bridges, telegraph poles and wind turbines, due to their versatility. But how to helical piles perform in extreme weather conditions?

Sub-zero Temperatures

Mixing and pouring concrete in cold climates can be tricky and fairly costly. When temperatures drop below zero, concrete must be kept from freezing throughout each stage of installation. If concrete is allowed to freeze, it may be damaged to such a degree that it is no longer fit for purpose. Helical piles, on the other hand, can be installed irrespective of the country’s climate or weather conditions.

Earthquakes

It is common knowledge to those in the industry that buildings with helical pile foundations are far less likely to be damaged by earthquakes. After the Christchurch earthquake of 2011, which took no less than 185 lives, experiments were carried out to prove the effectiveness of helical piles.

A team of experts led by Dr Amy Carato constructed a “giant sandbox” with ten helical piles and used a shake table to mimic the Christchurch disaster. As anticipated, the helical piles performed exceptionally well, with only inconsequential earth disturbance. The conclusion is that helical piles are a fantastic choice in earthquake prone areas.

Heavy Rainfall

Helical piles are treated to withstand high moisture below ground level. This means that, even in climates with heavy or frequent rainfall, they perform well. If the soils near the surface aren’t fit to stand the weight of the building then helical piles are the ideal option.

The versatility of helical piles with regards to climate, as well as fast installation, little disruption or noise and no waste soil to dispose of, all result in a convenient and cost-effective building solution.

4 Reasons to Use Helical Piles

In the mid-1800s, helical piles were often used in England for moorings and as the foundations of lighthouse structures. In recent years, helical piles are becoming more and more popular around the world due to their many benefits. They are a lot more environmentally friendly than their alternatives and highly cost effective. Here are various situations in which you might choose helical piles as the most suitable deep foundation option:

  1. When Access is Limited

Helical piles are often the preferred option when the conditions are of restricted or tight access. They can be sized appropriately to the accessibility of the project and installed using equipment of varying styles and sizes, from mini-excavators to large track equipment.

  1. When Time is Limited

Unlike concrete, which takes a long time to cure, helical piles are very quick to install using a hand-held device. What’s more, helical piles are designed specifically to suit the relevant ground conditions. This makes them ideal for time sensitive projects and also saves on the cost of labour. If it is ever necessary to remove them, helical piles are just as easy to take out and can be recycled time and time again.

  1. When the Site is Environmentally Sensitive

On certain sites, such as wetland and boardwalk projects, it’s highly important that there is limited disturbance. That’s why helical piles are an appropriate option, because they are installed using smaller equipment and cause a limited amount of disruption and vibration.

  1. When the Soil is Contaminated

When you’re deciding on which building foundation is most suitable, one of the factors to consider is the soil condition. Where helical piles are concerned, the soil below typically remains in place. This means that if the soil is contaminated, no additional costs are necessary for treating spoils or disposing of them in designated landfills.

What to Avoid When Choosing a Pile Foundation Company

The processes and apparatus involved in installing building foundations (such as helical piles) are continually progressing, while new tools and techniques emerge. At times, foundation companies fail to keep up with these inescapable changes, resulting in errors, safety hazards and poor service. If you have an upcoming building project and require a foundation installation company, here are four things you we advise you to avoid when hiring a pile foundation company:

  1. Lack of Experience

In certain industries, long-term experience is of the utmost importance because it means the company is well-practiced, knowledgeable and proficient. ScrewFast, for example, has nearly two decades worth of experience in a range of foundation industries and we have a training school for new installers. Try to avoid companies who do not have the experience necessary to provide a superior service.

  1. Neglecting Safety

Stay away from unprofessional companies that cut corners and overlook safety. In order to avoid injuries of both staff members and the general public, it’s important for companies to place a strong focus on safety throughout a project. At ScrewFast, we have avoided any serious injuries and are proud of efforts to protect those who manufacture, install and use our pile foundations.

  1. Incorrect Tools

Where geotechnical engineering is concerned, appropriate equipment is of course imperative. Many vendors lack the knowledge and resources required to correctly test, plan and execute a pile foundation project.

  1. Ignoring Ground Conditions

Before a building project can commence, a thorough and professional survey of the ground must first be carried out. Decisions can then be made about what approach will be taken and what equipment will be used to install the foundations. Our piles are manufactured to meet the specific requirements of the ground conditions. For instance, rock cutting teeth can be added to our helical piles in order to break through strenuous terrain.

What’s Involved in a Ground Survey

Before beginning a building project, it’s sensible to carry out a professional ground survey. Normally, trial holes are dug around the area so that a decision can be made regarding a suitable foundation. You will likely need to hire a structural engineer to perform this survey; it is too big a risk to take on the responsibility of designing your own foundations.

You cannot know what lies below ground without an adequate survey. There may be obstacles such as mine shafts or wells, which will require additional funding to remove or work around. For this reason, it’s always advisable to save some contingency funds.

If you hire an engineer, they will assess the area for big trees and boggy ground, as well as evaluating the condition of the soil. Unfortunately, if you build on substandard soil your new structure may end up with cracks and leaks due to ground movement. Essentially, the ground needs to be able to hold your building with limited amount of movement or change in shape.

If the ground conditions are not ideal, you may want to consider building a basement. Although expensive, it may work out as a more cost effective option because it will likely add value to the property and provide extra space for the inhabitants.

As well as an engineer, it’s also wise to discuss your plans with your neighbours and local builders because they may share some background information about the area and the success or failure of nearby buildings. It’s a good idea to speak to your local building inspector.

Balfour Beatty Associate Highways England Osbourne Associate Kier Associate