Basement Underpinning: Everything You Need to Know

January 12, 2023

Basement underpinning is a complex process, but it can make a big difference to your home’s stability, size, and value.

What does basement underpinning involve? And how will it improve your property?

In this guide, we’ll explore what the term means, the different underpinning methods used, the benefits of underpinning, and more.

What is Basement Underpinning?

Basement underpinning (otherwise known as basement lowering) involves digging into a property’s existing foundations and lowering them to set up a new space. For example, underpinning empowers you to transform your compact crawl space into a practical extra room safely.

Underpinning will also reinforce the property’s foundations, and any cracks detected in the foundation will be fixed during the process.

The method of underpinning chosen for your home will depend on a number of factors, such as ground water, the condition of the ground itself, and your property’s surroundings (e.g. other houses). There are four approaches to consider:

Mass Concrete

This is the most traditional basement underpinning method. A team will gradually dig into the existing foundation to create multiple holes, then fill them to create a stable new surface at a lower height. It is crucial that the surrounding walls remain structurally sound as the foundation is lowered.


The mini-piled approach involves inserting steel piles beneath the current foundations and then filling the space inside the resulting frame with resin or concrete. The piles are anchored to a subsoil layer several meters below.

Piled Raft

This underpinning method is typically used when subsidence disrupts the stability of an entire property. Floors are removed, and mini-piles are set up to create an even grid. A concrete raft is then placed over these piles before the floors are fully replaced.

Beam and Base

After the foundation is excavated, concrete beams are carefully positioned across concrete bases to handle the weight of the property overhead securely.

What are the Top Benefits of Basement Underpinning?

Here are the most important reasons to consider basement underpinning in your home:

Reinforce an Unstable Foundation

Basement underpinning is ideal if your home was built on a poorly constructed foundation or has become damaged over the years. Extreme weather or general wear and tear can take their toll on foundations, leaving your property potentially unstable.

Hiring an expert basement underpinning team will improve your home’s structural integrity for years to come.

Create More Space in Your Home

Basement underpinning in your existing home can expand the size of your current basement and create an exciting new space to enjoy. You can get more out of your property without needing to create extensions or cover more ground. It’s much more cost effective than either alternative.

You can turn your new basement into a gaming room with the latest consoles and a pool table, transform it into a stylish new bedroom for guests or a child who’s tired of sharing with a sibling, or turn it into a clean storage space.

And if you work from home and need a little more privacy sometimes, setting up a new basement office will give you an ideal opportunity to get away for a while.

Add Value to Your Home

Creating a bigger basement with stable foundations and plenty of room to walk, work, or play will boost the value of your property.

Buyers may be excited by the prospect of extra space and appreciate that the property’s structural integrity has been improved through a comprehensive renovation. That will prevent them from needing to pay for underpinning in the near future.

Update Essential Fixtures and Functions

Basement underpinning makes it easy to access key functions within your home, including the plumbing, insulation, and electrical wiring. You (or a professional) can assess them to identify potential issues or improvement opportunities.

If necessary, updating any of these will help make your home safer, more effective, and possibly more valuable if you plan to sell in the future.

A Great Opportunity for Basement Waterproofing

Basement underpinning also creates a terrific opportunity to protect your basement from water damage. After all, if you invest in creating a basement from scratch or expanding the current space, it makes sense to waterproof it, too.

Basement waterproofing is an effective way to keep rainwater on the outside of your home where it belongs. Interior and exterior waterproofing services are available.

Interior basement waterproofing involves setting up a trench along the foundation wall, installing a weeping tile system, and connecting that system to a sump pump or drain.

Exterior basement waterproofing begins with an excavation down to the foundation’s bottom, conducted by machine or hand. Any cracks are fixed and sealed, then a bituthene primer and delta membrane are applied to the foundation. New weeping tiles are installed to ensure that water leaves the property effectively.

You can take additional steps to protect your basement from water damage, too. For example:

  • Check that seals surrounding all basement windows are intact to prevent water seeping inside.
  • Make sure that all window panes and doors fit properly in their frames.
  • Fix any cracks or other signs of damage in windows and doors.
  • Inspect pipes in your basement to identify any leaks or other issues that could create water damage.

If water gets into your basement, it could create fertile breeding ground for mould, which can spread quickly and is potentially dangerous. Water damage can also affect a property’s structural integrity if it rots wood and damages walls.

How Can You Set Up Basement Underpinning in Your Home?

Aluneed is a dedicated, family-owned waterproofing company with more than 25 years of experience. We offer comprehensive basement underpinning and inspection services to stabilize structural problems and create more space. We are fully licensed and insured and handle all legally required inspections for your total peace of mind.

We can also protect your home from water damage with interior and exterior basement waterproofing services.

Contact Aluneed now to find out more about our basement underpinning services and book your free inspection.

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