Building regulations vs planning permission: the difference

Planning permission decides whether you may make the change. Building regulations decide whether what you build is safe and performs properly. They are separate consents, granted by different people, against different tests, and having one tells you nothing about the other. The most common mistake is assuming that permitted development rights mean no approvals at all. They remove the planning application and leave building control entirely untouched.

The one-line difference

Planning is about what and where. Building regulations are about how.

Planning permission looks outward: the size and appearance of the building, its effect on neighbours and the street, its use, and whether all that fits local policy. It is judged by planning officers against a local plan, and it involves discretion and public consultation.

Building regulations look inward: structure, fire safety, insulation, ventilation, drainage, electrical safety, stairs, glazing. They are national technical standards, judged by building control, and there is no discretion and no consultation. Either the work meets the standard or it does not.

Side by side

That last row is the one worth reading twice. Planning enforcement has time limits after which unauthorised development becomes immune. Building regulations enforcement no longer does.

Four combinations, and all four are common

Neither. Internal decoration, replastering, new flooring, a kitchen refit in the same layout with no electrical work. Nothing to apply for.

Building regulations only. This is the biggest category in renovation and the one people miss. Removing a load-bearing wall, converting a loft within permitted development, rewiring, replacing windows, adding a bathroom. All notifiable, none needing planning.

Both. A large rear extension beyond permitted development limits, a basement, a dormer on a principal elevation, anything to a listed building. Two applications, two timescales, and the planning decision has to come first because it can change the design.

Planning only. Rare in renovation, but it happens: a change of use with no building work, or hard landscaping and boundary walls above permitted heights.

The trap is the second category. Someone reads that their loft conversion falls within permitted development, concludes no permission is needed, and does not realise the structure, fire escape, stair geometry and insulation are all still being tested against national standards. Our guide to what building regulations cover sets out which Parts apply to which work.

Permitted development explained properly

Permitted development is a national grant of planning permission, given in advance by legislation for defined categories of work within defined limits. It is planning permission, granted generically instead of individually.

So when your extension falls within permitted development, you have planning permission. You simply did not have to apply for it. What you do not have, and never did, is anything resembling building regulations approval.

If you want written confirmation that your work is genuinely within the limits, a Lawful Development Certificate for a proposed use costs £274 in England, half the £548 householder application fee. For an existing use it is the full £548.

Worth checking the fee before you apply late in the year. The £548 householder fee applies from 1 April 2026, and a draft instrument published in July 2026 would raise it to £575 from 8 December 2026.

The two enforcement regimes are not alike

This is where the practical difference bites, and where a lot of comfortable assumptions are wrong.

Planning has immunity periods. Unauthorised development becomes immune from enforcement after a set time, and you can apply for a certificate confirming lawfulness. There is a route to sleeping soundly.

Building regulations no longer work that way. Section 35 of the Building Act 1984 became an either-way offence via the Building Safety Act 2022, which removed the magistrates' time limit, and the Planning Portal states there are now no time limits on prosecution.

In practice you are far more likely to meet the consequence at sale than in court. A buyer's solicitor asks for the completion certificate. A surveyor spots an opening with no paperwork and recommends a specialist report. A lender makes it a condition. That is the real enforcement mechanism for both regimes, and it does not expire.

The remedy differs too. For planning, a retrospective application. For building regulations, regularisation under regulation 18, available for work carried out on or after 11 November 1985 and judged against the standards in force when the work was done. Our guide to regularising work done without approval covers what the council can require, including opening up finished work.

Which order to do them in

Planning first, always, where both apply.

Planning can change your design. A refused application, or one granted with conditions on materials, height or fenestration, changes what you are building, and everything downstream has to follow it. Commissioning structural calculations before you know the shape of the building is a good way to pay for them twice.

Building control can then run alongside the build. A full plans submission has your drawings and calculations checked before you start. A building notice lets you proceed and be inspected as you go.

Realistic sequencing: design, then planning where needed, then structural design, then building control, then start on site. A householder planning application takes eight weeks from validation, and where a party wall notice is also needed that runs on its own clock, which can be two months. For a fuller picture of that sequence see our guide to what a house extension costs, which sets out the fees at each stage.

Who checks each one

Planning is your local planning authority, and only them. There is no private alternative.

Building control gives you a choice: the local authority, or a private registered building control approver, which is the term that replaced "approved inspector" under Part 3 of the Building Safety Act 2022. The individuals inspecting are registered building inspectors, registered in one of four classes according to the work they are competent to oversee. The registers are kept by the Building Safety Regulator, which since 27 January 2026 has been a standalone body sponsored by the Ministry of Housing, Communities and Local Government rather than sitting within the Health and Safety Executive.

If a private approver is proposed, check they appear on the GOV.UK register. If a builder tells you their "approved inspector" will handle it, that is the trade still using the old word, not necessarily a problem, but ask which registered body it is.

How Beams helps

The two consents fail differently. Planning delays a project at the start, visibly, with a date on a letter. Building regulations delay it at the end, invisibly, when a certificate does not arrive and a sale is waiting.

So we establish which consents a project needs before the design is fixed, run them in the right order rather than in parallel, and make sure the completion certificate is somebody's job rather than nobody's. Every builder then quotes from the same information.

That is part of what a Beams project commits to: one agreed price, payments released against milestones, and 12 months on the workmanship.

Common questions

Do I need building regulations approval if I have planning permission?
Almost certainly, and the two are unrelated. Planning permission says you may build it. Building regulations say how it must be built. Neither substitutes for the other.

Does permitted development mean no building regulations?
No. Permitted development is planning permission granted in advance by legislation. It has no effect whatsoever on building regulations, and this is the single most common misunderstanding in home renovation.

Which is more expensive?
Building control usually, for a domestic project. A householder planning application in England is £548 from 1 April 2026. Building control on an extension up to 40 square metres runs £700 to £1,300 including VAT, and higher in inner London.

Can I be prosecuted years later for building regulations breaches?
The time limit was removed. Section 35 of the Building Act 1984 became an either-way offence through the Building Safety Act 2022, and the Planning Portal states there are no time limits on prosecution. Planning enforcement, by contrast, does have immunity periods.

What do I actually need at the end?
A planning decision notice where an application was made, and a completion certificate from building control. In England the authority must issue a completion certificate in all cases where it is satisfied the work complies, within eight weeks of your completion notice.

Where this information comes from

Building regulations requirements, Parts and Approved Documents: The Building Regulations 2010, and the Approved Documents published on GOV.UK

Completion certificates, in all cases and within eight weeks: regulation 17(1) and 17(2), as currently in force in England

Regularisation and the 11 November 1985 date: regulation 18

Registered building control approvers and registered building inspectors: Building Safety Act 2022, Part 3, and the GOV.UK register

Building Safety Regulator as a standalone body from 27 January 2026: the Building Safety Regulator (Establishment of New Body and Transfer of Functions etc.) Regulations 2026

Enforcement and the removal of the time limit: Building Act 1984 section 35, as amended by the Building Safety Act 2022, and Planning Portal guidance

Planning fees, including the £548 householder fee from 1 April 2026, the £274 Lawful Development Certificate for a proposed use, and the draft instrument proposing £575 from 8 December 2026: Planning Portal fee guidance for England

Building control charges: Building (Local Authority Charges) Regulations 2010 and published council fee schedules

Both regimes differ in Wales, Scotland and Northern Ireland. This page describes England.