From top to bottom, and everything in-between
There have been a couple of interesting High Court cases recently regarding leasehold properties and a fight to determine who exactly owns the subsoil below and the airspace above. This issue is likely to become increasingly important with space so often at a premium, – particularly in the South East. Basements and lofts can, and do, provide valuable living space.
The legal position regarding freehold land is relatively straightforward. The general rule is that freehold ownership includes everything below the surface and the airspace above to a height necessary for the “ordinary use and enjoyment of that land”. The position when dealing with leasehold property however is slightly less straightforward.
In Gorst v Knight , the issues concerned the subsoil beneath a house in West London which had been divided horizontally into two maisonettes. The Gorsts were the leasehold owners of the downstairs maisonette which included a small cellar. Mrs Knight owned the freehold. The Gorsts had planning permission to dig out the cellar by about four feet and create a habitable space.
The dispute centred on whether the subsoil was included as part of the Gorsts’ maisonette. In summary, the court considered that the answer to the question depended on the actual terms of the Gorsts’ lease. Having considered those terms, the answer was no. This was bad news for the Gorsts as this meant that the works could not go ahead without Mrs Knight’s consent.
On the other end of the scale, Ralph Kline Ltd v Metropolitan and County Holdings Ltd  concerned whether the leasehold premises included the airspace. This was a relatively complicated case which saw two leases under scrutiny. However, we can take away from the judgment that the lease of an entire building, or the lease of a vertical division of a building, is likely to include the airspace above unless the lease contains evidence to the contrary. A horizontal split may have a different outcome.
It is clear from these cases that, in an ideal world, properly drawn leases should clearly identify the property and what is/isn’t included in the demised property. If your lease is unclear it would be prudent to seek advice from a legal expert before starting work on an expensive project!