Planning permission and building regulations approval are not the same thing. They are issued by different parts of the council, they assess different things, and you can need one without the other. Getting planning permission does not mean you have building regulations approval. Getting building regulations approval does not mean you have planning permission. Many homeowners complete a project having obtained one but not the other — and discover the problem only when they sell.
Building regulations set minimum standards for the design and construction of buildings, covering structural safety, fire safety, damp-proofing, insulation, drainage, ventilation, electrical safety, and access. They exist to protect the health and safety of people using buildings. The regulations are approved by Parliament and implemented through Approved Documents — Part A (Structure), Part B (Fire Safety), Part C (Moisture), Part E (Sound), Part F (Ventilation), Part L (Energy Efficiency), Part M (Accessibility), Part P (Electrical Safety), and others.
Building regulations approval is required for most structural works to a building, including all extensions regardless of whether they need planning permission, loft conversions, garage conversions to habitable rooms, any new internal structural wall or beam, new or replacement electrical installations in certain locations, replacement windows in some cases, underfloor heating, new bathrooms and drainage connections, and changes of use from commercial to residential. Critically: even if your project is permitted development and does not need planning permission, it almost certainly needs building regulations approval.
You do not need building regulations approval for most like-for-like repairs and replacements, small detached outbuildings under 15 square metres with no sleeping accommodation, greenhouse and conservatories below certain thresholds where they are not thermally connected to the main house, porches below 30 square metres, and some fence and boundary works. The exact scope is set by the Building Regulations 2010.
There are two main routes to building regulations approval. The first is Full Plans — you submit detailed drawings and specifications before work starts. The council checks them and issues approval. This is the preferred route for major works as it gives certainty before construction begins. The second is Building Notice — you notify the council that work is about to start and an inspector visits during construction to check compliance. This is faster but riskier as problems are identified during the build. Either route results in a Completion Certificate when the work is inspected and approved — this is the document you need when you sell.
A Completion Certificate is the formal confirmation from the council that building works comply with the regulations. It is required by mortgage lenders and solicitors when you sell or remortgage. If a previous owner carried out works — a loft conversion, a garage conversion, an extension — without obtaining building regulations approval or without getting a Completion Certificate, this will surface during conveyancing. Retrospective regularisation is possible through an application for a Regularisation Certificate, but it requires the works to be opened up for inspection, which can mean structural exposure.
The two systems assess completely different things. Planning permission is about whether development is acceptable in land-use terms — its impact on neighbours, on the character of the area, on highway safety. Building regulations are about whether the construction itself is safe and meets minimum standards. A building can have planning permission but fail to meet building regulations. A building can comply with building regulations but have no planning permission. Both are required for most building projects. Permitted development removes the need for planning permission. It does not remove the need for building regulations.
The planning history for a property shows all planning applications and decisions, but building regulations records are held separately. When we produce a planning intelligence report, we surface the planning record in full. For a complete picture on a purchase — particularly older properties where unauthorised works may have been carried out — we recommend asking your solicitor to specifically request building regulations completion certificates for any significant alterations.
Before you make any decisions, we retrieve the complete planning history for your property — including conditions, enforcement records, and legacy data that standard searches miss.
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