Basement Planning Advice

A cellar/basement conversion can be a solution for those who want more space but do not want to move out of their area, or want to avoid the costs associated with moving. A basement conversion can add 20 to 30% to the value of the property. Older style properties are usually more suitable for a basement conversion as they have suspended timber floors. There does not always need to be an existing cellar. It is possible to create a basement for a modern property, but this is more complex. Although It is messier than converting a loft it can produce more space and is not constrained by the pitched roof shape.The great advantage with basements is that they not only add a whole new floor, it's also space that can be used in many different ways.

With a loft extension, the space is used for bedrooms, studies or bathrooms. Basements are close enough to the ground floor area to be used as playrooms, nanny bedrooms and bathrooms when a new baby arrives, living rooms, kitchens or accommodation for relatives. With the demands of modern lifestyles, basements are increasingly being turned into leisure areas with home cinemas, pool and table tennis tables, home gyms or even swimming pools. You can also create an independent entrance or exit out into the back garden from the basement.

Planning Permission

Planning permission is not usually needed for a cellar conversion, but it may be required if it involves a change of use such as converting the cellar to a garage or an office. Planning permission may also be needed if the property is a listed building, or is in a Conservation Area. Local Council offices can give more information. Visit our Planning Links section to find the web site for your local Council Office.

Building Regulations

Whether or not you need planning permission for your basement conversion you will need to comply with a number of Building Regulations. These regulations cover such things as fire escape routes, ventilation, damp proofing, electrical wiring and water supplies. In addition, structural underpinning and foundation work is likely to be required. It is advisable to get expert advice on the design of your cellar conversion so that you can ensure all these areas are adequately covered before plans are submitted. There is also the Party Wall Act 1996 to consider. If you do not inform your neighbours about what you intend to do they could stop the work. More information can be found on our Building regulations page.

Heating and Ventilation

Heating and ventilation of your basement conversion is crucial. The cellar will need to be waterproofed. It may be possible to use a liquid for this but expert advice should be sought. Air bricks and extractor fans should be included in the design to ensure adequate ventilation of the new room(s). For the heating, any work involving gas must be done by a Corgi registered fitter, or you could use electric heaters or add radiators to an existing boiler if the boiler has sufficient capacity. It may also be a good idea to install a dehumidifier for those hot, sticky days.