Most people want more space in their homes, and more and more homeowners are beginning to look downwards to find this space, converting and extending their cellar to create a basement area underneath their property. Unlike loft space, which is best suited to adding more bedrooms, a basement, being located close to the main living areas and property access, can be used in a much wider variety of ways.

What are the Options for Creating a Basement?

If you want to create, or better utilise, some space underneath your home, there are three main options available:

1. Creating a basement as part of a new build
2. Renovating an existing basement or cellar
3. Creating a new basement in an existing home, either directly underneath, or by extending out into the garden, or to the front or side of the property

What Can I Use a Basement For?

A basement is ideal for creating additional living space for a large or growing family, for instance a playroom or home entertainment room. You could also reposition your utility room, boiler and storage, in order to free- up more living space upstairs in your main living areas.

A basement can also be given its own external entrance to create a self-contained unit that can be used as an annexe, or makes an ideal home office. A basement of this kind can also become a separate dwelling, but you will need specific and separate consent for this.

Is a Basement Conversion Cost-effective?

Whether a cellar conversion is cost effective or not will depend on the expense of the work relative to local property values. It is almost always advisable to add lower ground floor space in high-value areas, such as Central London and up and coming urban centres. Elsewhere, the potential added value should be more carefully calculated. An estate agent will be able to give you an idea about how much space is worth in your area, per square metre.

You should also keep in mind that a high quality and brightly lit basement living space with direct access to the back garden will be significantly more valuable than a dark and low-ceilinged converted cellar space. You should also consider the ceiling value for your location - most suburban areas, estates in particular, have a maximum value that it becomes very hard to surpass, regardless of what improvements you make.

If you are considering a loft conversion versus installing a basement, it is worth knowing that a straightforward cellar conversion costs about the same, although creating an entirely new basement costs nearly twice as much per m². However, a basement is likely to give you a greater amount of useable floorspace than a loft conversion will.

How Long Will the Conversion Take?

A simple cellar conversion can be completed within weeks. Converting a single-room cellar using a membrane lining system can be finished in as little as two to three weeks, which includes excavating the sump and fitting the pumping system.

Converting and extending a cellar beneath an entire house, which involves the underpinning of the existing structure, will most likely take several months.