How Can I Tell If My Home Needs Underpinning?

If you have cracks in your walls or floors, doors and windows that are not opening or closing correctly, you need to underpin service as soon as possible. It will help if you discuss with a professional, like restumping Sydney, before starting any work. So they can tell you how bad the situation is and what to do to fix it.

In this article, we will find the signs to check whether you need underpinning. If they are in bad condition, you must immediately take action to underpin your house.

What Is Subsidence?

Subsidence is a type of soil condition where the ground is sunk and cannot bear loads of a foundation. Different types of soil have different stability to hold on the structure. For example, clay-limestone soils aren’t stable enough to build a foundation.

What Are The Signs A House needs Underpinning?

The most common signs are cracks in the walls. The other signs include-


  • Cracks in the brick walls are bad enough to be seen inside and outside the building.
  • Cracks are found at the corner of the doors and windows
  • The crack is wider than 3mm in diameter.
  • Cracks form in the joints and extensions.


Although one or two cracks in the wall may not be an issue with subsidence, sometimes temperature fluctuations over long periods of time can cause cracks that have nothing to do with subsidence.

Is It Ok To Buy A House That Has Been Underpinned? 

If the underpinning is done under a certified and licensed foundation repair company, it’s safe enough to buy an underpinned house. Otherwise, it’s risky for you and the property. 


Underpinning is not what you can take as a DIY project – it’s best left to the experts. For more information on this topic, please check out our blog post “Can You DIY Underpinning?”

Do I Need A Permit For Underpinning In Sydney? 

Yes, you will need a building licence for underpinning or piering any project over $5000 (including GST) in Sydney, NSW. 

We recommend discussing this with your contractor before you start any work. They will arrange any permits on your behalf if required.

What are the disadvantages of underpinning?

The disadvantages of Underpinning are –

  • The process is a bit expensive compared to the other methods of foundation repair
  • It can become messy and noisy
  • There is a risk of potential damage to surrounding properties.
  • Underpinning can be lengthy and time-consuming.

What are the advantages of underpinning? 

The advantages of underpinning are –


  • Underpinning can restore the strength of a sinking house or has subsidence 
  • It can permanently prevent sinking a house
  • It can raise a sunken floor back to the ground.
  • It can repair cracks in the walls and floors by reinforcing a weak foundation.

Is Resin Injection As Good As Underpinning?

No, resin injection is not a better choice than traditional concrete underpinning. It’s a costly, time-consuming, inaccurate process that can fail much more commonly than traditional underpinning.


Though it costs more and takes longer, traditional concrete underpinning is more dependable than resin injection. Resin injection is less precise and has a higher probability of not working correctly.

Can Underpinning fail?

Yes, underpinning can fail when it’s not done properly and under expert hands. The longevity of the underpinning depends on the level of expertise the contractor has. So, select your contractor wisely.


Underpinning can fail due to other factors like soil condition change. For example, suppose you did underpinning to stop your house from subsiding due to a leaking pipe. In that case, tree roots could still damage the foundation.


Check out our blog when do you need to underpin, to know more.


If you see any of the following signs, your house may need underpinning. To be sure, ask an authorised foundation repair contractor for further evaluation. Though complex, this process can effectively stabilise a sinking or subsiding house. When choosing a contractor, qualification and experience are key to ensuring the job is done correctly.