Residential underpinning

Residential Underpinning: Understanding The Basics And When It’s Necessary

If you’re a homeowner, you might have heard of the term “residential underpinning,” but you might not know what it is or when it’s necessary. Residential underpinning is a technique used to strengthen the foundation of a house that has settled or shifted due to various reasons. In this article, we’ll discuss the basics of residential underpinning and when you might need it.

What is Residential Underpinning?

Residential underpinning is a process that involves strengthening and stabilising the foundation of a house. It’s usually done when the foundation has shifted or settled, causing cracks in the walls or uneven floors. The underpinning process involves extending the existing foundation’s depth or width by adding additional support to the foundation. This additional support can be in the form of concrete, steel, or helical piers, depending on the foundation’s condition and the soil type.

When is Residential Underpinning Necessary?

There are several signs that indicate that residential underpinning might be necessary. The most obvious sign is when you notice cracks in the walls or floors. If you notice cracks that are wider than 1/4 inch or if they appear in a diagonal pattern, this could be a sign of foundation problems. Another sign is if you notice that doors or windows are not closing properly, or if there are gaps between the frames and the walls.

Other signs of foundation problems include uneven floors, sagging roofs, or a chimney that’s leaning to one side. You might also notice that your house is starting to sink or settle, causing the floors to slope or become uneven. If you notice any of these signs, it’s important to contact a professional who can inspect your foundation and determine if underpinning is necessary.

Types of Residential Underpinning

There are several types of residential underpinning, each with its own advantages and disadvantages. The most common types of residential underpinning include:

  • Concrete Underpinning: This method involves excavating soil from under the foundation and pouring concrete to create a new foundation level. This method is usually used when the soil is stable and able to support the weight of the new foundation.
  • Steel Underpinning: This method involves driving steel piles under the foundation until they reach stable soil. The piles are then attached to the foundation to provide additional support. Steel underpinning is usually used in areas where the soil is unstable and unable to support a concrete foundation.
  • Helical Piers: Helical piers are steel piles that are drilled into the ground until they reach stable soil. The piles have helical plates that help to distribute the weight of the foundation evenly. Helical piers are usually used in areas where the soil is unstable or where access is limited.
  • Screw Piles: Screw piles are similar to helical piers, but they’re screwed into the ground instead of being drilled. They’re usually used in areas where there’s limited access or where the soil is too hard to drill.

The type of residential underpinning that’s used will depend on the condition of the foundation and the soil type. A professional engineer will be able to determine the best method for your home.

Cost of Residential Underpinning

The cost of residential underpinning can vary depending on several factors, including the size of the foundation, the condition of the soil, and the type of underpinning that’s required. On average, the cost of residential underpinning can range from $5,000 to $30,000 or more.

It’s important to note that the cost of underpinning is an investment in the long-term stability of your home. If you don’t address foundation problems, they can lead to further structural damage and potentially dangerous living conditions. It’s also worth noting that delaying underpinning can lead to increased costs as the damage worsens over time.

Hiring a Professional for Residential Underpinning

Residential underpinning is a complex process that requires the expertise of a professional. It’s essential to hire a qualified engineer or contractor who has experience with underpinning to ensure that the job is done correctly.

When hiring a professional for residential underpinning, it’s important to do your research and choose a company with a good reputation. You can also check online to ensure that the company has a good rating.

During the initial inspection, the professional will evaluate the condition of the foundation and soil to determine the best method for underpinning. They’ll also provide you with an estimate of the cost and time required to complete the project.

It’s important to ask questions and understand the process before the work begins. A reputable professional will be happy to answer any questions you have and provide you with information about the process and the materials that will be used.


If you notice signs of foundation problems, it’s important to contact a professional who can evaluate your foundation and determine if underpinning is necessary. Hiring a reputable professional with experience in underpinning is essential to ensure that the job is done correctly. 
Piling contractors in Sydney are experts in designing and constructing pile foundations for various types of structures. They utilize modern techniques and equipment to create a strong foundation that can withstand the weight of the structure and the forces acting upon it. By understanding the basics of residential underpinning, you can make informed decisions about the maintenance and repair of your home’s foundation.