cellar conversion

Your cellar conversion – before and after

When you need to create more living space, why not consider transforming the space underneath your home? If you live in a period property, you may already have a suite of rooms that were once used for coal and food storage. This may be the starting point for your project.

Otherwise you may have to retrofit a cellar space by digging down under your property. This is obviously a more costly procedure, but also gives you the scope to extend under your garden. It’s a big undertaking, but by dividing your cellar conversion before and after into a series of tasks you’ll create the clean and modern space you’re looking for.


Access and usable space

If you’re converting an existing cellar, how much available space is there? Will you need to open up a series of small rooms, and is there sufficient head height for the space to be habitable – 2.4m is recommended? 

You’ll also need to think about how light can be let into the cellar and what access there is for the work to be carried out. Start working with a professional basement company on the three key issues of natural light, ceiling height and damp issues.

Planning regulations and party wall agreements

Always check with the local authority planning portal before going any further with your plans. If you simply want to tank out your basement for storage, you may not need planning permission. Some basement conversions will also fall under permitted development, but it’s always worth checking for peace of mind.

You’ll also need to secure a party wall agreement with your neighbours, and it’s a good idea to get this even if you don’t plan any excavation work.


If you simply want to create storage, a simple membrane may be enough to create a damp free environment. A barrier system using cement will keep damp out of the cellar, but not deal with any underlying issues. The premium solution is the installation of a cavity drainage membrane plus a sump pump – expensive but the gold standard in cellar conversion waterproofing.


Your cellar conversion before and after should be taking shape. Now it’s time to look at design and layout.

Think about innovative ways to introduce light using internal glazing and cathedral height ceilings to borrow light from above. A staircase with a light well above is another smart way to borrow some natural light, or try using clear acrylic panels instead of traditional balustrades.

Your layout will also be dictated by the play of natural light. Keep storage and toilets in the darkest areas, and open up the rest using a light, neutral palette that bounces the light around. Keep spaces as open plan as possible, or use glazed folding doors to introduce some structure to the space.

With some thought and attention, your cellar conversion before and after will reflect your personal style and harmonise with the rest of the property.