Bringing Light and Air into your Basement design

Digging a basement to increase the house space has become more and more common in London over the last five years, a lot of Londoners have taken on the view of Improve don't move and to gain that extra space you can either go up and create a loft pod or go down and create a basement, or do both.

We are going to cover today basements and all the crucial points you should be considering when building a new basement if you want to feel like it is another part of the house and not in a damp and dark cellar!

It is a great way to use the space underground but to make the effort worthwhile you need to focus on two crucial topics: Light and Ventilation.


There are two ways to guarantee ventilation in the basement:

  • Choosing mechanical ventilation methods from simple air extractors to Positive Input ventilation (PIV), or Heat Recovery Units (MVHR).
  • Designing the basement in a way that allows natural air circulation. This can be obtained through open light wells or openable roof lights at the two opposite sides of the house.


There are certain situations where darkness would be acceptable, for example in gyms, wellness areas, cinema rooms, wine rooms, utility rooms, bathrooms, etc.

But if you are intending to use the basement as a living space or provide additional bedrooms you really want some natural light to come through.

How can you bring light into the basement? Let's have a look at some examples:

  • Internal walk-on glass - This can be achieved by installing the glass at the ground floor level where there is a source of natural light, this then shines into the sublevel basement creating a warm and inviting environment.



Internal Walk on Glass Designed by ASG Ltd, Built by BTL Property.


Internal Walk on Glass Designed by ASG Ltd, Built by BTL Property.

  • External walk-on glass - Some basements will extend through to the garden and external glass will provide direct sunlight gaining an even brighter space below.


External Walk on Glass Designed by ADE Architecture, Built by BTL Property.


External Walk on Glass Designed by ADE Architecture, Built by BTL Property.


Picture taken from

  • External Lightwells - Digging these at the edges of the house for part of the house width or for full width, this gives a huge amount of natural light and doesn't give you that boxed in feel that some basements can.



Picture taken from


Picture taken from

  • Internal Lightwells - This time digging internally and on one or more floors.



Internal Lightwell Designed by Granit Architects, Built by BTL Property.

  • Lowering the garden level and adding external steps to reach the ground level.


Designed by ADE Architecture, Built by BTL Property.


Designed by ADE Architecture, Built by BTL Property. Alternative picture taken from

  • Providing internal double heights so the light can spread on both floors.


Internal Lightwell, Designed by Ade Architecture, Built by BTL Property.

  • In more difficult situations where the space or the budget is limited it is possible to adopt clever systems to bring light downstairs like Tubular Skylights, Mirror shafts, or Fibre optic cable systems.


Picture Credits

If you have any questions relating to this article, why not ask our Architectural Design team?

Other articles in this section

Staircases in Architecture Staircases in Architecture Throughout architectural history, the staircase has been an important element which is the backbone to the space in our homes and generates...
Roof Terraces in Limited Outdoor Space Roof Terraces in Limited Outdoor Space Living in London, private outdoor space is a limited, but highly valued and sought after commodity. Gardens are usually small and often...
Open plan living space Open plan living space Those that live in London will be aware of how important it is to maximise the space available to you. Where it is not always possible to...
Indoor / Outdoor living Indoor / Outdoor living It may not seem like it now, as we struggle through the cold, dark depths of January but the summer will return and bring with it the long...