Rooftop developments are becoming a popular way for London property owners to utilise existing buildings. Adding floors, creating leisure areas, or selling airspace can generate new income.
These projects raise legal issues around ownership, planning, lease terms, and structural safety. Whether you are an investor, owner, seller, or occupier, knowing your legal position is key. This newsletter outlines the main legal points to consider.
Who owns the rooftop and airspace?
Before any development or sale, it is essential to confirm who holds title to the rooftop and airspace. In most freehold buildings, the owner will hold these rights, but in mixed-use or leasehold properties, they may belong to the landlord or be excluded from a lease.
Developers need a formal agreement to buy or lease the airspace. Rooftops can be sold as a new freehold title or under a long lease. These deals require clear terms, especially around title separation, overage clauses, and access rights.
Is planning permission required for rooftop developments?
In most cases, yes. Some upward extensions may benefit from Permitted Development Rights under The Town and Country Planning (General Permitted Development) (England) Order 2015. However, these rights are limited and do not apply in conservation areas, on listed buildings, or in areas where local authorities have restricted them using Article 4 Direction under the same legislation.
In London, additional planning rules often apply. Early engagement with the relevant local planning authorities and a well-prepared application are essential.
What about rights of light and neighbour disputes?
Developing upwards can reduce the natural light reaching neighbouring buildings. This may lead to legal claims based on rights of light. These rights are protected under common law and can arise through long-term use under the Prescription Act 1832.
In the case of HKRUK II (CHC) Ltd v Heaney [2010], a rooftop development was halted because it interfered with neighbouring light rights.
Investors should always commission a rights of light report before proceeding. Where disputes are likely, compensation or design changes may be needed.
Can rooftop work affect tenants and occupiers?
Yes, especially if the building has already been let to commercial tenants. Rooftop works can disrupt business operations, affect service charges, and lead to lease disputes. Tenants may claim the works interfere with their right to quiet enjoyment.
It is important to review lease terms to confirm the landlord’s rights and assess how the development will affect occupiers. Clear communication and agreed access or compensation terms can help reduce the risk of disputes.
What are the options for selling rooftop space?
There are several ways to structure a rooftop deal. An owner may sell the airspace outright as a freehold or grant a long lease to a developer. Each option has different implications for access, repairs, insurance, and service charges.
The legal documents must set out rights of support, fire safety compliance, maintenance responsibilities, and access for construction and future use. Overage provisions can also allow the original owner to benefit from any future increase in value.
Is your building suitable for rooftop development?
Even where planning permission is granted, building regulations must be followed. Rooftop structures must comply with safety, fire, insulation, and structural integrity rules. A detailed structural survey is essential before starting work.
Many older commercial buildings were not designed to support additional weight. Developers must factor in reinforcement costs and investigate whether any restrictive covenants in the title could block development.
How 3CS can help
Rooftop space can be a valuable asset for London property owners, offering opportunities to expand, generate income, or increase a building’s value.
Success, however, depends on a solid legal foundation. Owners, investors, and developers must navigate planning rules, rights of light, lease terms, and building regulations. The experienced commercial property team at 3CS can help you manage risk and maximise the potential of your rooftop development. If you’re considering this type of project, feel free to get in touch.
