Importance of Soil Type in Foundation Stability in Adelaide

Soil type is important in foundation stability in Adelaide because it provides information concerning soil fertility, drainage, water-holding capacity, and erosion potential. Professional underpinning contractors know that these details are essential in making informed land use and management decisions.

In this post, we will discuss soil classifications and how they relate to foundation stability.

What is the Soil Classification System in Australia?

The Soil Classification System in Australia is a way of grouping soils into different classes for easier identification. The four main types are organic soils, sands, loams, and clays.

There is also the Soil Class Foundation, which refers to the seven different soil classes in the country. The most common soil types in Adelaide are the following:

  • A: Sites with sand and rock that exhibit little to no ground movement due to moisture changes
  • S: Slightly reactive clay sites with minimal ground movement resulting from moisture changes
  • M: Clay or silt sites that are moderately reactive and may experience moderate ground movement due to moisture changes
  • H1: Sites with a high rate of ground movement, resulting in 40-60mm of surface movement
  • H2: Sites with a very high rate of ground movement, resulting in 60-75mm of surface movement
  • E: Sites with extremely reactive clay that experience extreme ground movement from moisture changes
  • P: Problem sites include soft soils such as soft clay or silt, loose sands, landslips, mine subsidence, collapsing soils, soils subject to erosion, and other unclassifiable sites.

Is a Soil Test Necessary for Underpinning?

Yes, a soil test is necessary for underpinning. These are the following reasons why it is needed:

Foundation Stability

The stability of a building’s foundation is heavily influenced by the physical properties and type of soil, including its moisture content and compaction. When the soil is not appropriate, it may be necessary to take additional measures.

Soil Settlement

Certain types of soil, notably clay, tend to expand and contract. This leads to settling or shifting over time, which can cause structural damage to the building. Soil testing can identify potential soil settlement issues, allowing the foundation to be constructed appropriately.

Groundwater Levels

The stability of a building can be impacted by groundwater levels, which can also determine the suitability of the site for septic systems or underground utilities. Soil testing can determine the level of groundwater in the area and assess its impact on the building.

Soil Contamination

Contamination of soil by pollutants such as heavy metals, chemicals, or petroleum products poses a risk to both human health and the environment. Soil testing can identify the presence of such contaminants and the extent of the contamination, allowing for appropriate remediation measures to be taken before construction.Would you like to know what to consider when underpinning a business property? Check out our post about it for more details.

Signs You Need Underpinning for Your Business Property

You need underpinning for your business property when you start noticing cracks, uneven flooring, and doors and windows not closing properly. Sloping floors and water damage are also some of the signs you require underpinning.

Once you start seeing these issues come up, it is best to seek help from foundation repairs specialists to avoid costly replacements.

In this post, we will discuss more about these signs to help you decide whether or not underpinning is the right solution for your property.

What Are the Signs You Need Underpinning?

The signs you need underpinning are:

  • Cracks in Walls or Floors
  • Uneven Flooring
  • Doors and Windows Not Closing Properly
  • Sagging or Sloping Floors
  • Water Damage

Let’s take a closer look at each one below.

Cracks in Walls or Floors

One of the most common signs that a commercial property needs underpinning is the appearance of cracks in walls or floors. These cracks can occur due to a variety of reasons but are usually caused by foundation settlement or movement. As the foundation shifts, the building’s walls and floors can crack or even separate.

Underpinning can help to stabilise the foundation and prevent further settlement or movement, particularly when different soil types are involved.

Uneven Flooring

Another sign that a commercial property may need underpinning is uneven floors. Uneven floors can make it difficult to walk or move around the building and cause doors and windows to stick or not close properly.

Adding support to the foundation through underpinning can help distribute the weight of the building more evenly and level out floors.

Doors and Windows That Don’t Close Properly

Doors and windows that have become difficult to close or open can also be a sign that a commercial property needs underpinning. This is often due to foundation settlement or movement, which can cause the building to shift and become uneven.

Preventing extra movement through underpinning can keep doors and windows secure, helping them open and close accordingly.

Sagging or Sloping Floors

Sagging or sloping floors can be a sign of serious foundation issues that require underpinning. If the foundation has sunk or settled unevenly, it can cause the floors to become uneven and even sag in certain areas.

An experienced underpinning provider can assess the situation on your property and provide the best approach to prevent having misaligned floors moving forward.

Water Damage

Water damage can also be a sign that a commercial property needs underpinning. Water damage can weaken the foundation and cause it to sink or settle unevenly, leading to various structural issues.

Underpinning can be an effective solution for addressing water damage in a commercial property. Providing necessary foundation support can help address cracks or other damage caused by the presence of water.Would you like the best tips for choosing an underpinning contractor for your next renovation? We made a post specifically for that. Read our blog for more information.

Common Mistakes to Avoid When Choosing an Underpinning Contractor

The most common mistakes to avoid when choosing an underpinning contractor are insufficient research, selecting the cheapest option, and not getting a written contract. Failing to check for licences and ignoring certain red flags are also some of the worst things one can do.

In this post, we will expand on these points to help you select the right underpinning provider in Adelaide.

What Are the Common Mistakes to Avoid When Selecting an Underpinning Provider?

These are the common mistakes to avoid:

Not Doing Enough Research

One of the most significant mistakes people make when choosing an underpinning contractor is not conducting enough research. It’s essential to conduct thorough research and gather as much information as possible about the contractor you are considering. This includes checking the company’s website, reading reviews, and looking for information about their licences and certifications.

Researching beforehand is essential, particularly when you need underpinning for a business property.

Choosing the Cheapest Provider

Choosing the lowest-priced option for your underpinning contractor may seem like a good idea at first, but it can lead to significant problems later on. The cheapest contractor may not have the necessary skills or experience to complete the project successfully. They may also use subpar materials or cut corners to save costs.

As a result, the work may be of low quality, and you may end up paying more in the long run to fix the problems.

Not Getting a Written Contract

Having a written contract is crucial when working with an underpinning contractor. A written contract outlines the scope of the work, the timeline, and the cost. It also protects you in case of disputes or misunderstandings, which is fairly common in such projects.

Make sure to read the contract carefully before signing it, and ask for clarification if you have any questions.

Not Checking for Insurance and Licences

Underpinning work is complex, and it requires a skilled and experienced contractor. Ensuring that the contractor you hire has the necessary licences and insurance is essential. The contractor’s licence and insurance protect you in case of accidents or damages that may occur during the project.

Be sure to verify the licence and insurance details before hiring the contractor.

Failing to Identify Red Flags

Ignoring red flags when hiring an underpinning contractor can lead to significant problems later on. If a contractor is unresponsive, does not show up on time, or seems unprofessional, taking these red flags seriously and considering other options is vital. A professional and reliable contractor will be responsive, punctual, and easy to communicate with.

If the underpinning contractor does not meet these criteria, it may be best to look for other options.Are you interested in learning about underpinning before renovating a property? Check out our blog for more details about it.

The Benefits of Underpinning for Renovations

The main benefits of underpinning for renovations are increased stability, allows for extensions, cost-effectiveness, increased value, and peace of mind. These pros are the main reasons residential and commercial property owners hire our team at Adelaide Underpinning Group.

In this blog, we’ll expand more on these benefits so you can better understand how underpinning can help with renovations.

What Are the Advantages of Underpinning for Renovations?

The advantages of underpinning for renovations are:

Increased Structural Stability

Underpinning provides a solution to structural instability in a building. A building’s foundation can become unstable over time due to a variety of factors, such as soil erosion, water infiltration, or the movement of the earth.

Underpinning involves extending or strengthening the foundation to ensure it can support the weight of the building and prevent further damage. Choosing an underpinning contractor experienced in renovations is essential to guarantee quality results.

Allows for Additional Floors or Extensions

One of the primary benefits of underpinning is the ability to add additional floors or extensions to an existing building. This is especially useful for buildings in urban areas where space is limited. By strengthening the foundation, underpinning can provide the necessary support to add more floors or extend the building’s footprint.

Doing so can result in more living space or additional features such as a garage, a home office, or a gym.

Cost-Effective Solution

Underpinning is often a more cost-effective solution than demolishing and rebuilding a structure. This is particularly true for buildings with historical or sentimental value. Demolishing a building can be expensive and time-consuming and may also require permits and approvals from local authorities.

Conversely, underpinning can be completed quickly and efficiently, often with minimal disruption to the building’s occupants. It also allows property owners to preserve the original structure while improving its stability and functionality.

Increases Property Value

A strengthened foundation can increase the value of a property. By underpinning a building, property owners can add extra floors or extensions, creating more living space and improving the property’s overall functionality. This can make the property more attractive to potential buyers and increase its resale value.

Additionally, a building with a stable foundation is less likely to require expensive repairs or maintenance in the future, which can also make it more appealing to buyers.

Peace of Mind

Underpinning provides peace of mind to property owners, knowing that their building’s foundation is secure and stable. This can be particularly important in areas that are prone to natural disasters, such as earthquakes or floods.

By underpinning the foundation, property owners can rest assured that their building is safe and secure and that they will not have to worry about costly repairs or structural issues in the future. This can also be beneficial for commercial property owners.Would you like to learn about concrete slabs? Check out our blog for more details.

Everything You Need to Know About Concrete Slabs

Concrete slabs are a vital component of many buildings and structures. They provide a sturdy and level surface for structures to rest on. However, a structure’s foundation will require underpinning, particularly when it needs reinforcing.

In this post, we will explore everything you need to know about concrete slabs, including their function, thickness, and strength, and the factors that influence their durability.

What is the Function of a Concrete Slab?

The main function of a concrete slab is to act as a foundation for buildings and other structures such as patios, driveways, and sidewalks. Concrete slabs are commonly used in areas with poor soil conditions to provide a stable surface for structures to rest on.

A concrete slab can also create a level surface on sloped terrain, making it ideal for outdoor living areas or pools.

Thickness and Strength of Concrete Slabs

The thickness and strength of a concrete slab will vary depending on several factors, including the size and weight of the structure it is supporting, the soil conditions in the area, and the climate. It is essential to ensure that the concrete slab is thick and strong enough to support the weight of the structure without cracking or settling.


The thickness of a concrete slab is typically determined based on the load it will be supporting. A concrete slab supporting a single-story residential home will be thinner than one supporting a high-rise building. The thickness of a slab can range from 4 inches to over 12 inches, depending on the load it will bear.


The strength of a concrete slab is measured in pounds per square inch (psi). The minimum strength of a concrete slab should be 3,000 psi, but it can be higher depending on the structure it will support. A concrete slab that will support heavy equipment or machinery may require a higher psi to prevent cracking and settling.

What Are the Factors That Influence Concrete Slab Durability?

These are the factors that influence slab durability:

Ground Preparation

The preparation of the ground is crucial to ensure the stability of the concrete slab. The area where the concrete slab will be poured should be cleared of any vegetation, debris, or loose soil. The ground should then be compacted to create a solid base for the slab. If the soil conditions are poor, additional measures may be necessary, such as installing a sub-base or adding drainage.


Reinforcement is necessary to prevent cracking and increase the durability of a concrete slab. It can be achieved by adding steel or fibre to the concrete mix. Steel reinforcement is commonly used in large-scale projects. In contrast, fibre reinforcement is often applied in smaller projects, such as patios or driveways.


Curing is the process of allowing the concrete to dry and harden. Proper curing is essential to prevent cracking and increase the durability of the concrete slab. Curing can be achieved by covering the concrete with a curing compound or by keeping it moist for several days. The curing process should be carefully monitored to ensure that the concrete dries evenly and does not crack.

Would you like to learn about underpinning for renovations? Check out our blog about it today.