Basement/Cellar Conversions

Converting a basement or cellar into a liveable space can be a cheaper and often quicker way to incorporate more space into your home. It can be a preferred alternative if you’re unable to expand into the loft or add a new extension.

Do I need planning permission?

This mostly depends on the scale of changes you plan to make. You probably won’t need it if you’re converting an existing cellar or basement into a liveable space, but if the changes reflect your home’s exterior, then it might be mandatory.

Ensure you check with your local authority before beginning any work. If you want to know more about the planning permission process, check out our recent blog.

Will it be expensive?

Figure touted by Real Homes magazine suggest an estimated price of a conversion like this can cost between £720 - £1,800 (per sq. metre), but for a whole new basement or cellar between £1,920 - £2,640.

Of course the prices above are tough estimates and it will depend on your plans for it – installing a play room will obviously cost significant less than a gym for instance.

Do I have to meet building regulations?

When carrying out a conversion such as this, you’ll need to meet required building regulations for it to be legally viable, such as:

-          Having an emergency escape route

-          Meeting the minimum levels of insulation

-          Having the right structural supports – work that’s carried out will need an approval from a building inspector

When putting together the budget for your conversion, make sure you add the cost of building regulation applications. These costs will depend on the work itself along with what your local council charges.


Another important job that needs to be carried is waterproofing. Underground areas like these are naturally damp, so make sure this doesn’t become an issue in the future.

Are you considering giving your basement or cellar a makeover? Let us know on Twitter @chewtonrose!