Edgeley Construction


Going Underground: The Lowdown on Basement Benefits

News | 04.03.21 | 0 comments

One of the biggest challenges that developers constantly face in London is that development sites are not only expensive; they are also hard to come by. Maximising the yield of every site – be it a development plot or a refurbishment opportunity, is therefore an essential strategy for leveraging the project’s full potential for profit and value.

Where possible, this often means building upwards, with high rise developments or rooftop extensions to maximise the amount of accommodation. But creating additional storeys above ground is not always viable, either for structural or for planning reasons. And, even when extra space at height is possible, It’s not the only way to increase the total footprint.

Basements are a great way to add extra space and achieve increased yield from a development. And yet they are often overlooked or dismissed because of assumptions about the risk and cost involved, and scepticism about the results than can be achieved. When planned and executed well, however, basements are not only viable in terms of build requirements and cost, they can offer spacious, attractive accommodation for commercial or residential use with plenty of natural light.


Why are so many developers reluctant to add basements?

The most common objection to basements from developers is the level of risk involved and the impact that unforeseen additional costs or delays could have on the yield of the finished project.

While it pays to consider risk and avoid unnecessary costs, it’s important to bear in mind that risk factors can be managed and properly assessed as part a cost /benefit assessment if properly identified during the project planning phase. Working with a construction contractor with experience of building basements is a clear advantage because it ensures that all risk factors are identified and buildability solutions are discussed to provide realistic costings and design enhancements that will reduce risk and improve the usability of the finished accommodation.

There is also a misconception that basements are always expensive, when, in actual fact, they can often offer an excellent return on investment. It’s essential to understand the ground conditions because a site where contamination or drainage is an issue may be less suited to basement construction. However, if there are no onerous obstacles and the development is being constructed on a vacant site, there is no reason to suppose that basement construction will be unduly risky, difficult or expensive. Furthermore, as the basement can usually provide additional accommodation for the entire footprint of the building, there is often a significant amount of square footage that can be added.

Another common misconception is that basement accommodation will be less appealing to occupiers or buyers and, therefore, command a lower price, which in turn will make the cost vs yield equation less attractive. These assumptions are based on the dark and claustrophobic basements that were often the norm in the past, but building design and methodologies have progressed to offer a world of possibility when it comes to basement construction these days. By incorporating light wells in the design and considering the aspect from within the basement accommodation, the assumed pitfalls of gloomy lighting and concrete views can be overcome with lots of natural light and biophilia. This involves careful consideration of light well and window positioning and a focus on landscaping, with the line of sight for basement occupiers in mind.

Moreover, taking basement space can even offer advantages to the occupier. There are thermal performance and acoustic benefits to basement accommodation and, used creatively, light wells can become a striking design feature.


Getting basements right

While many of the common misconceptions about basements are unfounded, a basement is not the right choice for every development and understanding whether below ground accommodation will suit the project or deliver a good return on investment requires thorough viability and buildability investigations.

For sites where there is a high water table, issues with drainage or contamination problems, a basement could be problematic.

For refurbishment projects, the disruption of basement excavation means that adding this extra space below ground should only be considered if the property is undergoing major renovations and the construction team will have vacant possession.

For all basement projects, it’s important to work with a contractor that has specialist experience and accredited expertise in basement construction. At Edgeley Construction, for example, we work in partnership with Newton Waterproofing and have undergone CSSW (Certified Surveyor in Structural Waterproofing) training to ensure our basements are protected against moisture ingress and are quality assured.

With space at a premium, basements are often the answer to generating maximum profit from a limited footprint. It is much more cost effective to include a basement as part of the initial build programme than adding one afterwards, so it pays to take expert advice from a construction company with basement experience.