Planning permission vs building regulations — two systems, both can apply

Almost every homeowner who runs into trouble on a building project does so because they treated planning permission and building regulations as the same thing. They are two entirely separate approval systems, run by different teams, against different rules, with different consequences for getting them wrong. You can need planning permission but not building regulations, building regulations but not planning permission, both, or — occasionally — neither. Getting one does not get you the other.

The one-line distinction: planning permission controls what you build, where, and how it looks and is used. Building regulations control how it's built — whether the structure is safe, warm, ventilated, drained and fire-resistant. This page sets out exactly what each covers, the two ways to get building control sign-off, and why the completion certificate at the end matters more than most people realise.

Planning permission: what, where and how it looks

Planning is about the use and appearance of land and buildings, judged against local and national planning policy. A planning authority (your borough) asks whether the development is acceptable in principle: its size, siting, design, impact on neighbours' light and privacy, and effect on the character of the area. Many domestic projects don't need planning permission at all because they fall under permitted development — the automatic rights granted by the General Permitted Development Order. Conservation areas, Article 4 directions, listed status and flats change that answer, which is what the Planning Permission Checker area check is for.

Building regulations: how it's built and whether it's safe

Building regulations are a separate set of national standards covering structural stability, fire safety, insulation and energy, ventilation, drainage, stairs, glazing and more. They apply to the construction itself, almost regardless of whether planning permission was needed. A loft conversion that's permitted development still has to meet building regulations for floor strength, escape windows, fire-resisting doors and stair headroom. Removing an internal wall needs no planning permission but absolutely needs building regulations sign-off for the beam that replaces it.

Which applies to common projects

Two ways to get building control sign-off

Building control can be handled by your local authority's building control team, or by a private-sector approver. Since 6 April 2024, under the Building Safety Act, the private route's providers are called Registered Building Control Approvers (RBCAs) — the role formerly known as "approved inspector" — and the individuals who inspect are Registered Building Inspectors. Either route can sign off a domestic project; only local authority building control can issue a regularisation certificate for past unauthorised work (see below).

• Building Notice — a quick route for straightforward domestic work. No detailed plans are checked up front; the work is inspected as it proceeds. Faster to start, but there's no approved set of plans, so the risk of a costly correction mid-build sits with you. Not available for some work.
• Full Plans — you submit detailed drawings that are checked and approved before work starts. Slower at the outset, but you get certainty, a documented approval, and a smoother ride with lenders and conveyancers. The route most professionals recommend for extensions, lofts and structural work.

Inspections and the completion certificate

Whichever route you choose, the work is inspected at key stages — foundations, damp-proofing, drainage, structure, insulation and completion. Never cover up work (close a foundation, board over a beam, backfill a drain) before it's been inspected; uninspecting it later can mean opening it back up. When the finished work complies, building control issues a completion certificate (or, on the private route, a final certificate).

What if work was done without approval? Regularisation

If building work was carried out without building control sign-off — by you or a previous owner — a regularisation certificate is the route to put it right. You apply to the local authority (only they can regularise; an RBCA cannot), pay a regularisation charge, and they assess the work as far as it can be inspected, sometimes requiring opening-up or remedial work. It is not automatic and not always granted, but it is the honest fix, and far cheaper than discovering the problem at the point of sale.

How this connects to your Planning Permission Checker report

Your Planning Permission Checker area report answers the planning half of the question — the conservation area, Article 4 and listed-building designations that decide whether you need planning permission, checked against official data. It does not assess building regulations, which turn on the construction detail of your specific scheme. For that, and for feasibility on anything structural or unusual, enquiries are routed to Hampstead Chartered Surveyors, an RICS-regulated practice (Firm Reg. 923064).