Basement conversions are becoming very popular within London recently. They add maximum space and are built for a variety reasons. A London Basement Conversion can be a new Self Contained Flat a Gym with Swimming Pool a Home Cinema or an addition of many New Rooms to the property. A basement conversion is an excellent option and provides an excellent return on investment.

At Capital Builders London we can extend or convert existing cellars or completely excavate, create and install a completely brand new basement with a head height of above 2.6 meters or more if required. A basement conversion adds between 30% to 60%.


Natural light is available within a Basement Conversion using the latest products and natural light distribution tricks including light wells for maximum daylight within Basement Conversions.

Our unique Basement Conversion method keeps mess to a minimum.


The house is not affected by mess or dust as everything is excavated from below the front window. The same area is used for access throughout the basement conversion project. Dirt is automatically transferred from below the home into awaiting skips.

What Are The Main Types Of Basement Conversion?

There are a number of different basement conversion types so you have the flexibility to build the basement that best fits your requirements. The names are quite self-explanatory, and the largest difference between the different types is the square footage that you can achieve.

The scene is now changing in the UK with house buyers, self‐build groups and established builders showing more interest in houses with basements. But there remains certain issues to be resolved to enable basements to become more of a norm in the UK.

The Most Common Types Of Basement Conversion: 

Basement conversions in Lindon.png

Under House Retro Fit Basement Conversion

Most basement conversions are under house retrofits, which means that we excavate a basement under a house which doesn’t currently have one. These come in two make sizes:

Half Foot Print:

A half footprint conversion is half the size of your home’s area – it provides less square footage but is cheaper to build as there is less excavation work and fewer building materials/days are required to finish the project.

Full Foot Print:

A full footprint conversion covers the entire area of the house and can increase the square footage of your home by around a third. We excavate to the existing walls of the house, but the basement work will extend beyond those to fit light wells.

The size of your basement conversion depends largely on your requirements, budget, and preferences. Some rooms may not require a lot of space, while others have minimum requirements – especially if you would like to build a subterranean garage or swimming pool.

Sub Basement Conversion London.jpg

Sub Basement Conversion

Sub-basement conversions are excavated under houses that already have a basement, but would like to expand further.

This type of conversion allows basement expansion. With this, you can add more levels to your basement for more rooms. This can create a multi-storey basement and offer yet more room for expansion.


In some instances, it can be difficult or impossible to arrange a sub-basement conversion, depending on what is underneath your home.

If you live close to transportation links or there are essential water pipes under you home, you may only be able to have a single-level basement conversion.


Basement Refurbishment London.jpg

Basement Refurbishment

Although Basement refurbishment is not actually a conversion, it is an extremely popular choice with clients looking to turn empty space in to a useful living space. 


The refurbishment involves remodeling your cellar or basement to make it more comfortable to live in, a more useful space or even to create an extra living space that you simply don't have room for in your existing property.


Under Garden Conversion

Under garden conversions create a true iceberg home by excavating well beyond the walls of the home to create a basement conversion that extends throughout the garden. This means that the basement of your house will be considerably larger than any of the other storeys. It also offers more opportunities to get natural light into the basement since roof lights can be fitted to get light into various parts of the room, rather than relying on a single lightwell at the front.

If you would like to know more about these basement conversion types and you want to know which is best for your home, we are open to consultations.

Capital Builders London also offers modern technique in basement construction. If your house does not have a basement but you think having one can increase the space of your home, then you can also count on us. We also excavate and construct new basements according to the demand of our clients.

We have experienced specialists in any all types of building works! If you want to find out more about how we could improve your home and pricing please send your question over email and we would be more than happy to answer.



9 Menlove Avenue, Liverpool, L18 1LS