If you cannot build up, why not build down? Converting and digging out basements is on the rise in the UK. It is a great way to add extra square footage to your property, especially when development of the current property has been exhausted.
If you are looking for inspiration as to what can be achieved when digging out a basement, at one of end of the scale, Claridge’s Hotel in Mayfair, London provides the perfect example. They have recently dug out 45,000 tonnes of clay to produce a new five storey mega basement conversion which houses a 7,000 square foot spa, amongst other amenities.
You are probably wondering whether you own the land under your building. The basic answer is yes. The Latin principle being, “Cuius est solum, eius est usque ad coelum et ad inferos,” which literally means, “whoever’s is the soil, it is theirs all the way to Heaven and all the way to Hell“. There are, however, a few caveats to this but the premise is correct.
If the property already has a cellar, planning permission may not be required for the conversion to habitable living space and could be deemed to be a permitted development. However, planning permission will be required if the property is in a conservation area or is a listed building.
If you need to “dig out” the basement, planning permission is generally required. Regardless of the planning status, building regulation approval will always be required and you will probably need to enter into a Party Wall Agreement with any nearby neighbours.
The Government had proposed to begin regulating subterranean development work and to establish a code of practice for such works with the introduction of the Subterranean Development Bill. However, this it yet to become law and it seems unlikely that there will be new Primary Legislation in this area for the foreseeable future.
Your Property title will need to be reviewed to assess whether any mines and minerals under your land belong to a third party. If so, digging out the basement could be a trespass. Were you to find resources such as gold or silver under your land, these would belong to The Crown.
If you are considering converting or digging out a basement, the Residential Property team at Coole Bevis LLP would be happy to review your title and advise you on any legal issues that you would need to consider.