It is commonly assumed that the owner of land owns from the core of the earth up to the heavens but technological advances in aerospace have shattered this view. Airspace is divided into upper and lower strata. Land owners can own the air in the lower stratum but not the higher. However, the boundary between the two is not fixed; it is dependent upon what can be defined as the airspace necessary for the ordinary use and enjoyment of the land (which is included) and that above (which is not). By definition, the owner of a 10 storey building will have more airspace entitlement than the owner of a single storey building.
Who can I buy it from?
It is relatively straightforward to buy airspace from private landowners. Problems arise when the airspace is over a river or highway. Enquiries should be raised of the local highways authority, the Environment Agency, the water authority and British Waterways in such a case. If you are unable to locate an owner, there is a presumption that – ad medium filum – that the landowners on either side of the highway own the subsoil up to the middle of the highway and the airspace above. Similarly, there is a presumption that land owners either side of a non-tidal river own the bed to the mid-point.
How can the air space be valued?
Airspace is measured by reference to the data used to derive altitudes on the basis of mean sea levels. It is measured on a residual basis by taking into account the projected rental yield or the level at which investors are prepared to buy (the value). This means you can transfer a freehold, leasehold or equitable interest in land or even charge the airspace!
What do I need to think about?
A section 177 (Highways Act 1980) licence from the highway authority is needed before any structure can be built or altered over a highway. A further licence (section 50 New Roads and Street Works Act 1991) is required if any apparatus is placed within the highway or parts need to be excavated. A stopping up order may need to be sought via the Government Office or a temporary diversion order may be required.
What else is there to think about?
Interference with existing rights to light, strain on the existing structure and support, whether the project will be considered an eye sore!
