Loft Conversion vs Basement Conversion

So you’re bursting at the seams and want to extend but the big decision is – do you go up or down?

There are definite plus and minus points for both – a light, airy loft makes great sleeping quarters, while a cool, subterranean basement could be a fantastic media room or family den. A lot will depend on the type of property you have, your family needs and of course, your budget.

Here are the main pros and cons:

Loft conversion


  • Great views, a wonderful feeling of space and light
  • Relatively cheap and straightforward if you can keep plans simple – i.e. staircases over existing staircases and plumbing over existing plumbing, using roof lights rather than dormer windows
  • Fabulous as a master ensuite bedroom or home office


  • There may be restrictions to the height you are able to build
  • You may have restricted head height in your loft space which will need to be taken into account
  • The space will be limited to the size of your loft space

Basement conversion


  • If you have an existing cellar, a basement conversion is relatively cheap and straightforward to do
  • Creates a fabulous, large space, ideal for a growing family, especially if you dig out under the garden too
  • Could have multiple uses as a great family den, media room, home cinema, home gym
  • Can have a separate access making it ideal for guest accommodation or home office
  • Adds a feeling of luxury – you could create a luxe basement kitchen/diner that opens into the garden, install an underground swimming pool or a bespoke temperature-controlled basement wine cellar and tasting cave
  • New technologies mean basements are light and airy so you don’t get the feeling you are under ground


  • Costs will increase if you need to excavate a new basement rather than convert an existing cellar
  • Time frames will also increase if it is a basement excavation rather than basement conversion
  • You may need planning permission depending on your local authority, especially for London basement excavations 
Peter Little
The Cool Basements Company Ltd.