An independent statutory check on building work, explained by the contractor who has to build to it.
Building control is the statutory check that building work meets the Building Regulations 2010. It is not planning permission. It is not something a builder can grant, and it is not something you can buy your way around. In England the check is carried out by one of two bodies: your council's building control department, or a private firm registered with the Building Safety Regulator as a Registered Building Control Approver. Both are independent of the people carrying out the work. Every London borough plus the City of London runs its own building control function, and each sets its own fees.
Most readers arrive here for one of two reasons. Some want their borough's department, and the fastest route to that is the council's own website. Others are about to start work on a house and want to know whether approval is needed, what it costs, and what happens if it is skipped. This page answers the second question in full. We are a building contractor. We build to the approved design, arrange and attend the inspection stages, and hand over the certificate at the end. We are not a building control body and we do not sign off our own work.
Planning permission governs what you may build. Building regulations govern how it must be built. They are separate pieces of legislation, decided by different teams, and consent under one gives you nothing under the other.
Planning is about land use, size, siting, height, appearance and the effect on neighbours and the street scene. Building regulations are about whether the thing will stand up, resist fire, keep water out, ventilate, insulate and carry electricity safely. A loft conversion can be fully permitted development and still need a building regulations application, because permitted development is a planning concept only.
This is the single most common misunderstanding we meet on site. A homeowner is told the extension does not need planning permission, hears the word "permitted", and assumes there is nothing else to do. There almost always is. Internal work runs the other way: taking out a load-bearing wall usually needs no planning consent at all, but it is building work and it needs building regulations approval.
| Question | Planning permission | Building regulations approval |
|---|---|---|
| Controls | Use, size, siting, height, appearance, effect on neighbours | Structure, fire, damp, drainage, ventilation, insulation, stairs, glazing, electrics |
| Decided by | The borough planning department | Borough building control, or a Registered Building Control Approver |
| Main law | Town and Country Planning Act 1990 | Building Act 1984 and the Building Regulations 2010 |
| Can it be avoided | Yes, if the work is permitted development | No, unless the work is exempt or is not building work |
| Document at the end | Decision notice or lawful development certificate | Completion certificate, final certificate or regularisation certificate |
Our building regulations guide covers the regulations themselves, and our permitted development guide covers the planning side.
You need building regulations approval for almost any structural, thermal, drainage or electrical alteration to a home, and for any extension that does not fall into a narrow list of exempt classes. Approval is required whether or not planning permission was needed.
The regulations apply to building work as defined in regulation 3 of the Building Regulations 2010, and to a material change of use. A useful test is whether the work touches the structure, the weather envelope, the heating, the drainage or the electrical installation. If it does, assume approval is needed and check.
Work that normally needs approval:
Work that normally does not need approval:
Two traps sit inside that second list. Forming the structural opening between the house and an exempt conservatory or porch is itself building work and needs approval. And extending the main heating system into a conservatory removes the exemption, because the Part L energy efficiency requirements then apply.
Budget roughly £400 to £1,650 including VAT for a typical domestic project with a London council. A structural opening sits at the bottom of that range and a large extension or loft conversion sits at the top. Fees are set borough by borough, so the number for your postcode will differ from a neighbouring borough's.
Local authority charges are made under the Building (Local Authority Charges) Regulations 2010. Each council publishes its own scheme, usually revised each April. Below are two real London schedules, both operative from 1 April 2026, reproduced so you can see the actual spread rather than a national average. Registered Building Control Approvers quote commercially and are not bound by these schedules.
| Work, as published | Total fee | Fast track full plans |
|---|---|---|
| Extension or loft conversion up to 30 sq m | £859.00 | £945.00 |
| Extension or loft conversion over 30 up to 60 sq m | £1,183.00 | £1,301.00 |
| Extension or loft conversion over 60 up to 100 sq m | £1,406.00 | £1,547.00 |
| Garage conversion up to 30 sq m | £673.00 | £740.00 |
| Detached non-habitable building up to 40 sq m | £673.00 | £740.00 |
| Other works, estimated cost £0 to £5,000 | £512.00 | not offered |
| Other works, estimated cost £10,000 to £20,000 | £879.00 | not offered |
| Other works, estimated cost £20,000 to £30,000 | £1,069.00 | not offered |
| Work, as published | Full plans, inc VAT | Building notice, inc VAT | Regularisation, VAT exempt |
|---|---|---|---|
| Domestic extension under 40 sq m | £1,122.00 | £1,122.00 | £1,210.00 |
| Domestic extension 40 to 60 sq m | £1,386.00 | £1,386.00 | £1,507.00 |
| Domestic extension 60 to 100 sq m | £1,610.40 | £1,610.40 | £1,749.00 |
| Loft conversion under 40 sq m | £1,108.80 | £1,108.80 | £1,199.00 |
| Loft conversion 40 to 60 sq m | £1,188.00 | £1,188.00 | £1,276.00 |
| Garage or outbuilding to habitable use | £818.40 | £818.40 | £880.00 |
| Structural opening, simple through lounge | £396.00 | £396.00 | £440.00 |
| Structural opening with additional works | £607.20 | £607.20 | £649.00 |
| Underpinning up to 6 metres | £818.40 | £818.40 | £880.00 |
| Removal of chimney breast | £396.00 | £396.00 | £440.00 |
Read those two tables side by side and the point makes itself. The bands are not even drawn in the same places. Havering steps at 30, 60 and 100 square metres, Hillingdon at 40, 60 and 100. A 35 square metre rear extension is £1,183 in Havering and £1,122 in Hillingdon, and the reason has nothing to do with the building.
The aggregation rules also run in opposite directions. Havering allows separate extensions built at the same time, including a room in the roof, to be added together into a single band. Hillingdon states that loft conversions and extensions may not be aggregated and that a separate fee is always payable. Doing an extension and a loft in one programme therefore attracts one charge in one borough and two in the other. Check your own council's scheme before you budget.
Three things the fee never covers. It does not cover architectural drawings. It does not cover the structural engineer's calculations, which are a separate appointment and a separate invoice. And it does not cover putting right work that fails an inspection, since a council may add supplementary charges for incomplete plans, revised schemes, work not ready for inspection and non-compliant work. A full plans approval also lapses if the work has not started within three years of the application date, under section 32 of the Building Act 1984.
Both routes are legally equivalent for a normal domestic project, and either can sign your work off. The council is usually the simpler choice for a one off householder job. A private approver is more common on developer led and commercial work.
The private route changed name and status recently, and much of the web is still out of date on it. Under the Building Safety Act 2022 the title "approved inspector" no longer exists. Private building control businesses had to register with the Building Safety Regulator as Registered Building Control Approvers, with registration opening in October 2023 and becoming mandatory on 6 April 2024. Separately, the individual people who carry out inspections must appear on the register of building inspectors from the same date, and working as an unregistered building inspector is a criminal offence. If a firm still calls itself an approved inspector in 2026, check the public register before you appoint it.
When you use an approver, the firm gives an initial notice to your council and issues a final certificate to the council on completion. When you use the council, it gives you a completion certificate directly. Three things only the council can do. It is the only body that can issue a regularisation certificate for work already built. It is the only body with the statutory enforcement powers. And control reverts to it if an approver's initial notice is cancelled, for example because the firm stops acting or the job stalls, which is a genuinely awkward position to be in mid-build.
One category is not a choice at all. Since 1 October 2023 the Building Safety Regulator is the building control authority for higher-risk buildings, meaning those of at least 18 metres or at least 7 storeys with two or more residential units, plus hospitals and care homes. Ordinary house extensions and loft conversions are nowhere near this threshold.
Expect this to change. On 20 May 2026 the Building Control Independent Panel reported that the system in England is fragmented and conflicted, and recommended removing the client's ability to choose its own regulator. The government response the same day accepted the guiding principles, committed £55 million over three years to inspector capacity, and signalled a consultation on limiting building notices. Nothing has changed for a homeowner booking a job today, but the choice described above may not exist in a few years.
Use full plans for anything structural, and a building notice only for small, simple, low risk work. The formal name for the first route in England has been an application for building control approval with full plans since 1 October 2023, though almost everyone still says full plans.
With full plans you submit drawings, specifications and the structural engineer's calculations, and the building control body checks them before you build. The decision must come within five weeks, or two months if you agree to the longer period. You end up holding a document that says the design was approved, which matters to lenders, to future buyers and to you if anything is ever disputed.
With a building notice you submit no drawings for checking. You give notice and may start once at least two days have elapsed since the end of the day the notice was given. There is no approval to hold, and no protection if the design turns out to be wrong. The risk sits entirely with you: if the inspector rejects what has been built, you take it out and do it again at your own cost. For a single storey extension with a steel beam over a knocked through opening, that is a poor trade, particularly since both London schedules above charge the same either way.
A building notice is not permitted in three situations, and only three, set out in regulation 12 of the Building Regulations 2010. It cannot be used where the Regulatory Reform (Fire Safety) Order 2005 applies to the building, or will apply after the work, which catches flats, blocks with common parts and mixed use buildings. It cannot be used where the work includes erecting a building fronting onto a private street. And it cannot be used where paragraph H4 of Schedule 1 applies, which is building over or close to a public sewer.
Worth correcting a widespread error here. Many secondary sources state that Part P electrical work forces a full plans application. It does not. Regulation 12(6A) requires either a building notice or a full plans application where the work involves a new circuit, a consumer unit replacement, or any addition or alteration to existing circuits in a special location. A special location means the zone around a bath or shower, or a room containing a swimming pool or sauna heater. That is a duty to notify, not a restriction on which route you use.
Work that has already started cannot use either route, and needs regularisation instead. Choose full plans if any of the following applies:
Inspections happen at the points where work is about to be covered up, and the completion certificate is the document issued at the end confirming the building control body is satisfied. That certificate is what a buyer's conveyancer will ask for, sometimes decades later.
The statutory notification duties in England changed on 1 October 2023 and are now simpler than most websites suggest. Under regulation 16 of the Building Regulations 2010 you must give at least two days' notice before commencing, notify the body within five days of work being regarded as commenced, and notify within five days of completion. The England version no longer prescribes stage-by-stage notifications for foundations, damp proof course, oversite and drains. Those individual stages are now set by the building control body as a risk based inspection plan for your project.
So the list below is what happens in practice on a London house extension, not a statutory sequence. Confirm the exact schedule with your inspector at the start, because it varies between bodies and between projects.
The inspector checks the work against the Approved Documents, which are the government's statutory guidance for each part of Schedule 1. You do not have to follow them, but if you depart from them you have to demonstrate compliance another way, and on a domestic job almost nobody does.
| Part | Subject | Where it bites on a domestic job |
|---|---|---|
| A | Structure | Beams, lintels, foundations, load paths, underpinning |
| B | Fire safety | Loft conversion escape route, fire doors, protected stair, alarms |
| C | Site preparation and resistance to moisture | Damp proof course, damp proof membrane, ground conditions |
| F | Ventilation | Extract in kitchens and bathrooms, background ventilation, trickle vents |
| H | Drainage and waste disposal | New runs, building over sewers, rainwater |
| K | Protection from falling, collision and impact | Stair pitch, headroom, guarding, balustrades, safety glazing |
| L | Conservation of fuel and power | Insulation values, glazing, heating controls, air tightness |
| P | Electrical safety | New circuits, consumer units, work near baths and showers |
Two points on the certificate. Where the council supervises, it issues a completion certificate, normally within eight weeks of completion, provided it is satisfied. Where an approver supervises, it issues a final certificate to the council instead, and that is the equivalent document. Keep whichever you receive with the deeds. Part P electrical work is often certified separately by a registered electrician under a competent person scheme, and that certificate should be handed over too.
The work does not become legal with age, and since 1 October 2023 the council's enforcement window is ten years rather than twelve months. Section 36 of the Building Act 1984 now allows a local authority to serve a notice requiring the removal or alteration of non-compliant work at any point up to ten years from the date the work was completed. Contravening the regulations is punishable by an unlimited fine and up to two years' imprisonment, and a council's powers over a building that is actually dangerous are not time limited at all.
In practice the consequence most homeowners meet is not enforcement. It is a stalled sale. A buyer's conveyancer asks what alterations have been made and whether building regulations consent was obtained. If a loft conversion or a knocked through opening has no paperwork, the buyer's solicitor and the buyer's lender will both want something before exchange. You have three realistic options.
Be clear about what indemnity insurance is. It covers the legal and enforcement risk. It does not cover the cost of putting the work right, it does not make the work compliant, and it does not tell you whether the beam over your opening is adequate. It also becomes void the moment anyone approaches the council about the work, which means taking a policy and applying for regularisation are mutually exclusive. If you are selling and moving on, a policy often closes the deal. If you are buying and intend to live under that roof, regularisation, or at the very least an inspection by a structural engineer, is the better answer.
We build to the approved design and we manage the building control process around it. We do not carry out building control, and no contractor can.
On a typical extension or structural alteration that means we appoint and coordinate the structural engineer who produces the calculations, submit the application to your borough or to your chosen approver on your behalf, give the statutory commencement notice, build to the approved detail rather than to whatever is quickest, book each inspection at the right point in the programme, meet the inspector on site, deal with anything raised, and hand you the completion certificate at the end with the electrical certificates and the warranties.
What we do not do is decide whether the work complies. The inspector is independent of us, is not paid by us, and is not obliged to agree with us. That independence is the point of the system. We are not a building control body, not an approved inspector, not a Registered Building Control Approver, not a structural engineer, not a surveyor and not an architect. We hold no trade accreditation. What we bring is a founder with over 30 years of hands-on experience on London houses, and a habit of building things the way the drawings say.
Plenty of readers do not need us at all. If your work is exempt, do nothing. If you are replacing a consumer unit or a boiler, a registered electrician or a Gas Safe registered engineer can self-certify it under a competent person scheme without any application. If you are trying to reach your borough's building control department, go to the council's website. And if a certificate is missing on a house you already own, your first call is the council, not a builder.
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FAQ
Usually yes. Planning permission and building regulations approval are separate regimes under different legislation. Permitted development rights remove the need for a planning application, but they have no effect at all on building regulations. Loft conversions, rear extensions and garage conversions frequently need no planning permission and always need building regulations approval. The reverse also happens: removing an internal load-bearing wall normally needs no planning consent but is building work and does need approval. Treat them as two separate boxes to tick.
A full plans application must be decided within five weeks, or two months if you agree to the longer period. A building notice needs no decision at all, and you may start once at least two days have elapsed since the end of the day the notice was given. After completion, a local authority normally issues the completion certificate within eight weeks. Note that approval lapses if the work has not commenced within three years of the application date, under section 32 of the Building Act 1984.
No. Building control is an independent statutory function carried out by a local authority building control department or a Registered Building Control Approver. A contractor can submit the application, build to the approved design and attend the inspections, but cannot approve the work or issue the certificate. The narrow exception is self-certification under a competent person scheme, where a registered electrician or heating engineer certifies their own specific installation. That covers the circuit or the boiler, not the extension around it.
Effectively yes, but the term approved inspector no longer exists in law. Under the Building Safety Act 2022, private building control businesses had to register with the Building Safety Regulator as Registered Building Control Approvers, which became mandatory on 6 April 2024. The individual inspectors must also appear on the register of building inspectors from the same date. Any firm still trading as an approved inspector in 2026 should be checked against the public register before you appoint it.
Around £860 to £1,650 including VAT for a single storey rear extension with a London council, depending on floor area and the borough. Havering's 2026/27 schedule charges £859 for an extension up to 30 square metres and £1,406 for one of 60 to 100 square metres. Hillingdon charges £1,122 under 40 square metres and £1,610.40 for 60 to 100 square metres. Every borough sets its own scheme, and the size bands are not drawn in the same places. The fee excludes drawings and structural calculations.
You have three options. Ask the council or the supervising inspector for a copy, in case one exists. Apply to the council for a regularisation certificate, available only from a local authority and only for work started on or after 11 November 1985, which may require opening up and remedial work. Or take building regulations indemnity insurance, typically £20 to £300, which covers enforcement risk but does not make the work compliant. A policy is voided if anyone contacts the council, so the last two options are mutually exclusive.
Consents and Approvals
Building control is one of several consents a London project runs through. These are the others.
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Tell us what you are planning. We will say which consents it needs, arrange the application and book the inspections around the programme.
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