Published on 16 Jun, 2017

Did you know that living space in Britain is now the tiniest in western Europe? Traditionally, Brits have started coming up with ingenious solutions to this problem. The most popular approaches are to convert existing spaces like basements, garages, and lofts or extend a property horizontally or vertically. Recently, however, there’s been a new trend among homeowners, especially in London and big metropolitan centres across Britain. Creating an under-house extension can provide you with nearly 50% extra living space and increase your floor area without the need to sacrifice any garden space.


If you already have a basement, converting it is a cost effective way of adding more space and extra value to your home. In many cases, however, homeowners either don’t have a suitable basement structure that can be easily converted into a living space or they don’t have a basement at all. In this case a new basement extension needs to be created from scratch. There will probably be extra work, costs and time involved compared to other home renovation projects, as such an endeavour involves expensive and time-consuming excavation and/or underpinning that need to be planned and executed by experienced basement extension specialists. Depending on the size of the property, the amount of work required and its complexity, the project will typically take between 12 and 20 weeks. The end result, however, will definitely be worth the wait.


Due to the basement being underground the surrounding ground soil provides excellent insulation, making the basement extension an environmentally friendly option. In some basements with proper insulation the temperature can be easily maintained without additional heating at a constant 25 degrees Celsius even in the winter. Sounds great, right? And, that’s not all:

  • Underpinning can actually stabilise an old building. In construction or renovation, underpinning is the process of strengthening the foundation of an existing building or other structure.
  • If done right, the basement extension will add value to your property.
  • Waterproofing will make the whole house drier and healthier, while better insulation makes it more energy efficient.
  • The extension will free up space in other parts of the house.
  • The basement is an adaptable space and can be easily modified depending on your needs.

Basement Extensions Create Extra Space


Before deciding on spending lots of money and resources on your brand new basement extension, you should definitely consider these shortcomings:

  • Depending on the architecture of your house, you may not be able to get enough light in.
  • It’s expensive and there is always a risk that you may not recoup the costs when you decide to sell. Make sure you make the calculations.
  • Converting an existing basement from a storage area to a habitable space does not require planning permission, but the creation of a new basement will require Building Regulations approval.
  • The job is relatively complex. It’s bound to be disruptive, noisy and messy.
  • One important factor to take into consideration is comfort. Make sure your basement does not feel too disconnected from the rest of the living space.

Historically, basements have been used as cellars, boiler rooms or storage areas, which by today’s standards could be considered a waste of valuable living space. When it comes to deciding what to do with this newly rediscovered and reutilized extra space, the possibilities are unlimited. For ideas and inspiration check out our What Would You Do, If You Had an Extra Room? blog post.

#FlattroTip When designing your basement space, make sure you nail the right balance between functionality and décor. The best way to do this is to hire a professional. If you have no idea where or how to begin to decorate your basement or you have an idea, but need help tying the pieces together, hiring a professional interior decorator is one of the smarter decisions you can make.

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