Building regulations are the consent most London renovations actually turn on. Planning permission gets the attention, but for work inside an existing house it is usually not needed at all, while building control very often is, and it is the one that produces the paperwork a buyer's solicitor will ask for years later. This guide sets out which work needs approval, the three routes for getting it, how long each takes, and where a London project picks up extra consents on top.
Building control is not planning permission
They are separate systems with separate bodies, separate applications and separate consequences. Planning permission is about what the building does to its surroundings: size, appearance, impact on neighbours. Building regulations are about whether the thing you have built is safe, warm, ventilated, drained and accessible. You can need both, either or neither, and getting one does not help you with the other.
For most internal renovation work in an unlisted house outside a conservation area, that split means no planning permission and definite building control. It is the reverse of what most clients expect.
The work that needs building regulations approval
The Building Regulations 2010 cover the construction and extension of buildings, so any extension, loft conversion, basement or structural alteration is in scope without argument. What catches people out is the list of alterations. GOV.UK names these specifically as work that might need approval:
- Replacing fuse boxes and connected electrics
- Installing a bathroom that will involve plumbing
- Changing electrics near a bath or shower
- Putting in a fixed air-conditioning system
- Replacing windows and doors
- Replacing roof coverings on pitched and flat roofs
- Installing or replacing a heating system
- Adding extra radiators to a heating system
Two of those matter more than the rest on a typical London renovation. Replacing windows in a period property is notifiable work, which is why FENSA or a similar certificate exists. And adding radiators, which sounds like a plumbing errand, is covered because it changes the heating system's performance.
The list is not exhaustive. GOV.UK's own wording is that you could need approval, or need to follow special rules, for work not listed, so the safe move on anything uncertain is a call to a building control body before the trade starts.
When you do not have to apply yourself
The most useful exemption is the competent person scheme. If the work is done by someone registered under one of these schemes, they self-certify compliance and notify building control on your behalf, and you never make an application. This is how most electrical work, boiler replacements and window installations are handled in practice, and it is why you should ask a contractor which scheme they are registered with before you engage them rather than after.
The certificate they issue is the document that proves compliance later. Collect it, file it, and put it with the deeds. A missing FENSA or Gas Safe certificate is one of the most common reasons a sale stalls.
Emergency repairs are the other case: you do not need advance approval to repair a boiler or heating system in an emergency, though there are rules that still have to be followed.
Choosing who approves the work
For work that does not involve a higher-risk building, you can use either your local council's building control department, applying through the Planning Portal, or a private registered building control approver. If you choose a private approver, they tell your local authority about the work by giving an initial notice.
In London the practical difference is responsiveness. Borough building control departments vary enormously in how quickly they book inspections, and on a project where the steel is going in on Thursday, an inspector who can attend on Thursday is worth paying for. A private approver also travels with you across borough boundaries, which matters if your designer or contractor works across several.
The three application routes
Full plans. The thorough option: you submit drawings and calculations and get a decision, normally within five weeks, or within two months if you agree to the extension. The advantage is that the design has been checked before anyone builds it, so a problem surfaces on paper rather than in steel. Once the work is finished and complies, you will usually get a completion certificate within eight weeks.
Building notice. For smaller projects only. You submit the notice and can start work two days later, but you do not get formal approval in the way full plans gives you. Nothing has been checked in advance, so the risk of an inspector requiring changes to work already built sits entirely with you. It suits simple, well-understood jobs and suits nothing structural.
Regularisation. Retrospective approval for work already carried out without consent. It is available only from a local authority building control body, not a private approver, and only for work carried out after 11 November 1985. Expect to have to open up completed work so it can be inspected, and to make alterations before a regularisation certificate is issued. It is the expensive way to arrive at the same place, and it is usually triggered by a sale.
Higher-risk buildings, which in London means a lot of flats
A higher-risk building is one that is at least seven storeys or 18 metres high and is any of: a building with two or more residential units, a hospital, or a care home. Work on those buildings goes to the Building Safety Regulator rather than to a council or a private approver, and BSR approval is needed before work starts.
There are exceptions for existing higher-risk buildings: BSR approval is not needed if the work is exempt from building regulations, is done under a competent person scheme, or is an emergency repair. But if you are renovating a flat in a tall London block, establish the building's height and storey count early, because it changes who you are dealing with and how long the approval takes.
A flat renovation usually carries a separate consent as well. Most leases require the freeholder's written permission for alterations, which is a legal process quite distinct from building control: see our guide to a licence to alter in a leasehold flat.
Fees, and the levy that starts this autumn
Local authorities set fees based on their costs, and what you pay depends on the type of work, the number of site inspections, the number of dwellings in the building and the total floor area, which is why extensions are quoted by square metre. Private registered approvers negotiate their fees directly with you. There may be no fee at all for work carried out solely for a person with a disability.
One new cost to be aware of: from 1 October 2026, applications for building control approval and initial notices for certain residential buildings may be subject to the Building Safety Levy. It is aimed at residential development rather than at householder alterations, but if your project creates new dwellings, ask your building control body whether the levy applies before you budget.
What happens if you skip it
Three things, in ascending order of expense. The person doing the work can be prosecuted and fined. The building control body can require you to pay to put faulty work right. And, most commonly, you simply will not have the certificates of compliance that a buyer's solicitor asks for, which surfaces at the worst possible moment: mid-chain, with the price under renegotiation.
Indemnity insurance is sometimes offered as a cure. It is not one. It covers the risk of enforcement action, not the risk that the work is unsafe, and it does nothing about a floor that will not carry the load.
The other London consents that stack on top
Building control is rarely the only approval a London renovation needs. Structural work in a terrace or semi triggers the Party Wall etc. Act, and the notice periods there are the ones that decide your programme. A listed building needs listed building consent for interior alterations, which does apply inside. A conservation area affects the exterior rather than the interior, as our conservation area guide explains. And removing structure has its own sequence, covered in removing a load-bearing wall.
Sequenced properly, none of these is a problem. Sequenced badly, the party wall notice alone can add two months to a start date. Our project timeline guide shows where each consent sits, and everything else is on the Vertigo Interiors homepage.
Frequently Asked Questions
Do I need building regulations approval for internal alterations?
Often, yes, even where planning permission is not required. Structural work, new bathrooms involving plumbing, electrics near a bath or shower, replacing a fuse box, installing or replacing a heating system, adding radiators, replacing windows and doors, and replacing roof coverings are all named by GOV.UK as work that may need approval. If a competent person scheme member does the work, they self-certify and you do not apply yourself.
How long does building regulations approval take?
Under a full plans application you can expect a decision within five weeks, or within two months if you consent to the longer period. A building notice is much faster: you can start work two days after submitting it, but nothing is formally approved in advance. A completion certificate normally follows within eight weeks of the work finishing, provided it complies.
What is the difference between full plans and a building notice?
Full plans means your drawings and calculations are checked before you build, and you receive formal approval. A building notice is for smaller projects only, gives no formal approval, and lets you start almost immediately. With a building notice the risk of being told to change completed work is yours, so it is unsuitable for anything structural.
Can you get retrospective building regulations approval?
Yes, through a regularisation application, but only from a local authority building control body and only for work carried out after 11 November 1985. You will probably have to open up finished work for inspection and make alterations before a regularisation certificate is issued. It is usually cheaper to apply properly first time.
What is a higher-risk building?
A building at least seven storeys or 18 metres tall that is also any of the following: a building containing two or more residential units, a hospital, or a care home. Work on higher-risk buildings needs building control approval from the Building Safety Regulator before it starts, rather than from a council or a private approver.
What happens if work was done without building regulations approval?
The person who did the work can be prosecuted and fined, the building control body can make you pay to correct faulty work, and you will not have the certificates of compliance a buyer will ask for. The usual remedies are a regularisation application or, where the work is recent and accessible, opening it up for inspection.
Do I need building control approval for new radiators?
Adding extra radiators to a heating system is on GOV.UK's list of alterations that may need building regulations approval, because it changes the system's performance. In practice a heating engineer registered under a competent person scheme will self-certify the work and notify building control, so you will not make an application yourself. Keep the certificate.
Sources
- GOV.UK, building regulations approval, when you need approval: gov.uk
- GOV.UK, building regulations approval, how to apply (routes, timings and fees): gov.uk
Checked on 23 August 2026. Building control fees and inspection practice vary between local authorities and private approvers; confirm the route and cost with yours before starting work.