If you’re looking to expand your property, building a basement could be the best way to maximise the use of limited space by extending below ground level.

In the UK, it’s possible to convert existing cellar spaces into basements or to underpin an existing house and excavate a new basement from scratch.

In this article, the team at Danford, Brewer & Ives explains everything you need to know about building a basement under an existing house in the UK.

How to Excavate a Basement Under an Existing House?

Given the scarcity of land in the UK, building a basement beneath our feet is often the best option if you’d like an extension. Basements can add huge value to properties while providing a functional living, entertainment, storage or utility space that’s highly customisable.

But can you build a basement under an existing house in the UK? The short answer is yes, and it’s possible even if there’s currently no subterranean space (such as a cellar) below the property.

This can be achieved by excavating the area beneath your home, through a method that’s known as underpinning. Underpinning is a technique used to extend existing cellar spaces in order to create more room, while the technique can also be used to create an entirely new space that can be converted into a basement.

The underpinning process sees qualified engineers excavating the soil below the foundations. This space can be filled with concrete or other sturdy construction materials that ensure the foundations of your property remain as strong as before. Above this, you have a newly excavated space that forms the basis of your basement.

Once the underpinning has been achieved, the basement can be created. As part of this process, your engineers will need to factor in integral structural elements like drainage, waterproofing and lighting. When the basement has been built, the final stage is the interior design, decoration and furnishing.

How Much Does It Cost to Build a Basement?

Now to the all-important question, how much does it cost to build a basement? Unfortunately, there’s no exact figure, as there are a number of variables that any basement conversion project needs to factor into its budget.

The most important variable is often whether or not there’s an existing cellar space below the house. If there is, this can seriously lower costs, as the existing work can be expanded on. If you need to start afresh, a new build basement cost in the UK will be significantly higher, as more work will be required.

Other important variables include:

  • The size of the basement conversion
  • The complexity of the basement conversion
  • The materials used in construction
  • The interior design, furnishings and decoration

We should note that building a basement is a serious project that requires a comprehensive budget in order to be completed safely. Always use a professional service and the best available materials for the best results.

How Long Does Building a Basement Take?

As with cost estimates, it’s difficult to pinpoint the exact timeframe in which it takes to build a basement. This also depends on a number of variables, but you can expect any basement conversion to take a number of months from start to finish.

To help you visualise the process and how much time this may take, it’s important to consider that there are several main stages involved in the design, excavation and construction of a basement beneath an existing house in the UK. These are:

  1. Planning, initial design and surveying
  2. Excavation and building work
  3. Interior design and decoration

These factors will of course vary. The larger and more complex a basement conversion is, the longer it will take to complete. If you have an existing cellar space, it can lower the timeframe whereas excavating a basement from scratch will take much longer.

Contact Danford, Brewer & Ives to Find Out How We Can Make Your Basement Plans a Reality

If you’re planning on building a basement, Danford, Brewer & Ives has an expert team of basement converters ready to assist.

From the initial survey and design stages through to excavation, underpinning, waterproofing and interior decoration, we provide a professional, full-service basement conversion package tailored to your needs.

Contact Danford, Brewer & Ives today to find out how we can make your basement dreams a reality.