Underground development is not a new concept; the infrastructure sector springs to mind with city metro systems and The Channel Tunnel connecting the UK to mainland Europe. However, with misconceptions of underground buildings being dark and damp, real estate hasn’t quite unlocked this market yet. But is this a missed opportunity? Or are we right to keep our head above ground?  

Whilst the UK and Ireland don’t typically build down, underground housing is already a widely used option for countries with densely populated cities like Japan and China. Over the past 30 years, subterranean development seems to have gained traction and it is now not uncommon to find underground housing across the Americas and mainland Europe too. In the historic city centre of Amsterdam, converting a souterrain level into a full-fledged living level is a popular activity. The UK, however, has been slower to pick up on this trend. But with underground development holding a multitude of environmental benefits, it may be something we see appearing more frequently as UK real estate focuses closely on the green agenda.  

Where do we start? 

Underground development doesn’t necessarily require reinventing the wheel entirely, but just simply making use of buildings already standing – and the space that sits below them. Repurposing redundant spaces can be a great use of existing buildings and infrastructure, while being a cost-effective method too. There are lots of buildings, especially in city centres, where converting underground spaces could provide a sustainable alternative to extending up or building new. Basement spaces often have large floor plates that could lend themselves to use as restaurants, galleries, performance spaces, bars, spas or flexible workspaces.

Solutions and sustainable advantages 

Other than being able to take advantage of fabulous architectural and heritage features that might exist and can be incorporated and showcased in new designs, repurposing existing underground space has significant sustainable advantages, such as saving the embodied carbon in the existing building fabric. Underground spaces are also much better for regulating temperature, which means less heating and cooling requirements; a big plus on the EPC grading system. Noise pollution is also likely to be less of a problem, making them more peaceful places with less daily background noise; another positive when looking at the social aspect of buildings. Whilst there may be limited natural lighting to play with, there are plenty of low energy lighting options available and which can still make a room feel bright. In a time where many are looking for environmentally conscious and energy efficient construction, there may be a solution in underground real estate. 

So, what is the catch? 

The nature of being underground does create challenges for development though. A lack of natural ventilation would mean there is a need for likely costly improvements, as would the probable absence of disabled and emergency access. There are also a number of other environmental considerations that will need to be properly inspected and considered. Flooding from groundwater inundation, for example, is one of the biggest environmental risks. Old underground structures are likely to have dated waterproofing that could lead to water ingress causing mould and bacteria on walls and rusting of mechanical and engineering plant. There is also an increasing risk of flash flooding from street-level water run-off, which is becoming more prevalent due to climate change. In some geographical locations, risks from naturally occurring radioactive radon gas would also need to be considered. Likewise stringent gas inspections would need to be carried out to ensure there is no risk of toxic or explosive gasses, which can accumulate in confined spaces.  

Let’s build down  

Despite the challenges, in a time where space is limited and at a premium, sub-surface development holds the potential to provide further leisure and entertainment spaces for tourists and locals, create new housing for residents, and increase sustainable practice in real estate. As with any development, thorough due diligence is needed to ascertain a scheme’s viability, and when regarding underground development, talking to an environmental consultant who understands the risks involved is vital before proceeding. If you’re looking to build down, or would like to simply find out more, get in touch with our Head of environmental consultancy Vikki Aitkenhead.