User:Cellar Conversion Expert/Cellar Conversion

Cellar Conversions UK
Cellars and Basements are both rooms below ground.

Cellars tend to be low grade environments suitable for storage purposes and basements are higher grade and used for habitable purposes.

The British Standard BS8102 (1990) defines four grades of underground structure based on useage: -


 * Grade 1 Car parking
 * Grade 2 Low grade storage and workshops
 * Grade 3 Normal Habitable grade
 * Grade 4 Totally controlled environment for Special purposes.

A Cellar conversion is when a low grade structure grade 1 or 2 is converted to a higher grade structure grade 3 or 4. This process invariably includes the installation of a waterproofing system plus finishng works and mahy or may not include an increase in headroom.

If headroom is to be increased, this is usually achieved by lowering the cellar floor but in some cases may involve the raising of the ground level floor (cellar ceiling). If the cellar floor is to be lowered the foundations my require deepening (a process known as underpinning) or alternatively given additional lateral support (side pinning).

Any work to the party walls has has to comply with the party wall act which basically requires the client to notify neighbouring property owners in writing of the intended work and a condition survey of any party walls (and nearby structures and ground) to be made by a party wall surveyor. This enables any defects arising from the work to be identified.

By its very nature a cellar conversion project involves a change of use and therefore invokes the relevant building regulations. It is therefore necessary to contact the Local Authority Building control department and obtain approval for the specification of works. Key points include natural lighting, ventilation and the provision of a secondary means of escape in the event of an emergency. (all three requirements may be achieved by using an escape window well or a 'scapeweil for short.

Planning permission, on the other hand may not be required unless the property is in a conservation area, is a listed building, or the works will alter the external appearance of the building. In any case it is advisable to check with the local authority before the works are undertaken, allowing sufficient time for the necessary approvals to be obtained, should the prove to be necessary.

The British Structural Waterproofing Association (Design Guide to Waterproofing Existing Basements) describes the various methods of waterproofing. For existing structures this normally falls into two categories:-


 * Tanking or
 * Drained Cavity System

Other methods of waterproofing - external drainage and the use of integrally waterproof concrete being more appropriate for new construction.

The use of the drained cavity method has become more prevalent over the last 15 - 20 years and is clearly identified as the most reliable method in the British Standard. The reason for this additional reliability stems from the fact that the structure does not have to hold back water pressure as it does for tanking and minor movement and even cracking of the structure does not cause a CDM system to fail, whereas it would be catastrphic for a bonded tanking system.

Cellar conversion projects have become increasing popular in the UK during the late 1990's and early 2000's as the cost of moving house has become more expensive (For example increases in stamp duty and compulsory vendor information packs). Popularity has also been fueled by improvements in waterproofing technology and a growing industry of expert contractors that have perfected the techniques of extending basements horizontally underneath houses and adjoining gardens. In some areas (London for example) it has even become a fashionable thing to do. Cellar Conversion Expert (talk) 03:07, 17 July 2009 (UTC)