What is underpinning and why is it needed?
Underpinning is the process of strengthening the foundation ground underneath an existing structure.
Traditionally underpinning involved excavation of the soil underneath the building and replacing it with a stronger material – usually a form of concrete.
There are three reasons why you may need underpinning services, these are:
- For a building conversion/extension
If you’re going to convert the structure above the ground by adding another level to a building, or to something that has another function than the original purpose such as converting a residential building to a commercial or industrial unit, you may need to strengthen the ground below to accommodate the increased load.
- For protection from future issues
If it’s identified that the foundations of your structure are neither strong nor stable, or if nearby excavation works would affect the soil that supports your existing structure, the ground beneath it may need strengthening to help prevent future issues.
- To rectify current issues that the building is facing
This is the most common reason for needing underpinning work completed on your property. Underpinning helps to stabilise the foundations and re-level buildings that have subsided, helping to return them to their previous state. Traditional underpinning would typically take weeks / months, however, Mainmark’s world-leading resin injection solution can complete the task and bring the building back to level in as little as one day.
What are the different types of underpinning?
The fundamentals of underpinning date as far back as the 15th century. The methods of underpinning have progressed with time. Along with traditional techniques we now have modern alternatives to underpinning that can be completed in one day and without the need for vacating the structure.
Here are some of the underpinning methods:
- Mass concrete underpinning
Mass concrete underpinning is a traditional and most widespread method of underpinning. It involves excavating the ground below the structure in boxed sections and then filling these by pouring concrete. This is carried out from the outside/perimeter of the structure and is suitable for shallow foundations.
- Piled underpinning
Piled underpinning is used when the foundation load needs to be transferred to stable soils at deeper depths as the soil is inadequate to bear the weight of the structure above. Other reasons for piled underpinning include environmental concerns regarding excavated soil or restricted access to the construction site. Piled underpinning involved the removal of internal floors so that a grid of steel-cased piles could be installed and filled with concrete for the structure to sit on.
- Computer-controlled grouting
Computer controlled grouting uses a multitude of injection ports to deliver high-mobility grout into the ground, under precise computer control, to gently raise the structure in a non-invasive way. Each computer can be programmed to control up to 128 injection ports at once, enabling lifting of very large areas or complex heavy structures. The non-invasive injection ports are only 25mm-40mm in diameter and remain in place for the duration of the work. The self-contained grout batching and control centre is housed within a self-contained unit to minimise onsite footprint and is demountable when necessary to enable access to restricted areas of buildings or infrastructure.
- Resin injection underpinning
High tech, advanced engineered resin injection underpinning is an efficient way to rectify subsidence and re-level structures. Using a process likened to keyhole surgery, an expanding polyurethane resin mix is delivered into the ground via an array of small-bore injection tubes (typically 16mm diameter around the perimeter of the building or 6mm if carried out inside). A chemical reaction and consequent expansion occurs as the components mix together, upon entry to the ground. This reaction and expansion strengthens the ground and the building is returned to level in a controlled manner.
Resin injection underpinning
Resin injection underpinning is a non-invasive alternative to the traditional underpinning of a building that is experiencing subsidence. A modern alternative that can save time and money it fills voids and compressed soil, increases the ground’s load-bearing capacity and can re-level the building or structure.
Traditional methods of foundation underpinning can be complicated, costly and disruptive. They involve excavations from under the foundations and a labour-intensive process of filling these with concrete or other filler material in order to strengthen the foundations. The work can last weeks and often even months. During this time the building needs to be vacated.
Underpinning a house
Underpinning a house using traditional methods aims to improve the foundations underneath. The treatment is needed when the original foundations can no longer support the building. This is often caused by issues with the soil supporting the foundation. Underpinning a house using traditional methods can be a complicated, lengthy and costly process but there are modern proven underpinning alternatives now available.
If your home suffers from subsidence, or you suspect it may, enlisting the help of experts as soon as possible is essential to ensure the problem is dealt with quickly and does not worsen. Underpinning contractors and geotechnical engineers can help diagnose the problem and advise on the best course of treatment options and costs involved. Alongside traditional underpinning contractors, Mainmark’s methods offer a modern, proven subsidence treatment methods – an option that may prove more suitable for your requirements.
One of the first things you will probably wonder when you discover that your home may be suffering from subsidence is how much remediation methods, such as underpinning, will cost you. When calculating the cost of traditional underpinning for a residential home, the numbers can quickly go up. There are various methods of dealing with house subsidence and the cost of each method can be very different. may also be suitable for saving your home and saving you money.
Underpinning alternatives with minimal disruption
Mainmark’s ground improvement technologies are cost-effective and reliable alternatives to traditional underpinning. Our methods cause little or no disruption and work can often be completed in a day.
Our underpinning alternative technologies are non-invasive. This means that it is not necessary for building occupants to vacate the property during the work taking place. Building contents can remain in place. Treated roads, paths, driveways and concrete slabs can be used again after only a few hours.
Mainmark technologies – effective alternatives to underpinning
Teretek® – Underpinning alternative with resin injection
Teretek® resin injection technology can be used as anunderpinning alternative when the foundations can no longer support the building. We drill small holes through the ground-bearing slabs or the foundations into the deteriorated soil strata underneath. These holes are then used for injecting our specialist resin formula, filling cracks and voids, compacting the soil and restoring the structure to its correct level.
JOG – Underpinning alternative with computer-controlled grouting
JOG computer controlled grouting uses a high-mobility cementitious mix. This mix is pumped into multiple injection depths during a monitored process that deploys laser sensors and computers. This is a precise method that is a proven alternative to underpinning. It consolidates weak ground and delivers specific, engineered ground improvement outcomes, regardless of how complex the project is.
Why Choose Mainmark?
Delivering exceptional outcomes to our
clients, partners and team
Our world-leading ground engineering technologies achieve safe, accurate and economically delivered outcomes. We understand that ground engineering can be complex and no single method suits every project. We work with our clients and partners to recommend the right solution for each challenge.
Mainmark ground improvement solutions have been proven for over 30 years. Our ground engineering specialists have worked on over 30,000 projects worldwide, from straightforward residential subsidence to post-earthquake remediation in Japan and New Zealand. We aim to be the best at solving your ground problems with minimal disruption.
Our experienced team has a wealth of knowledge in residential, commercial and industrial buildings, as well as highways, rail, utilities and infrastructure. Our ground engineers can raise and re-level buildings, providing support and improving ground performance.
The combination of our proven ground improvement technologies and our experienced ground engineers enables us to re-level and re-support buildings affected by subsidence across various sectors.
Our problem-solving approach and recommendation of ground engineering solutions sets us apart from the competition. The complexity of ground improvement requires a range of state-of-the-art technologies to meet both project and client requirements.
We are trusted to present effective and creative solutions to many types of ground engineering problems in a wide range of sectors, including residential, industrial, commercial, civil engineering and infrastructure.
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Arrange a site assessment in three simple steps:
Submit your enquiry using our online form. Include a brief message about the type of foundation issues you are experiencing.
Our friendly customer service team will be in touch to schedule a site assessment that suits you.
One of Mainmark’s experts will visit your home or property, assess the damage and determine the likely cause. They will establish the approach needed, create a plan specific to the needs of your building and provide you with a detailed quote.
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Mainmark Ground Engineering (UK) Ltd.