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building control vs approved inspector

Approved Inspector vs Council Building Control: Which to Pick

Approved inspector vs council building control for an extension in England: what the terms now mean, how fees, speed and enforcement differ, and how to choose.

The Extension Works 31 October 2026
Approved Inspector vs Council Building Control: Which to Pick

Approved Inspector vs Council Building Control: Which to Pick

Inspector checks an extension wall during construction

For a home extension in England, you can have your building regulations work checked either by your local council or by a private provider. The private option used to be called an “approved inspector”. Since April 2024 the official term is “registered building control approver” (RBCA). Both can approve plans, inspect the work and sign it off. The differences lie in fees, flexibility, local knowledge and what happens if a problem cannot be resolved.

This guide explains the change of name, compares the two routes honestly, and shows how to decide for a single-storey rear extension.

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TL;DR

  • “Approved inspector” is the old name. The Building Safety Act 2022 replaced it with “registered building control approver”, and the change took effect on 6 April 2024.
  • For a typical extension, you can choose your council or a private RBCA. Both are legitimate, and both are now overseen by the Building Safety Regulator.
  • Councils have enforcement powers that private approvers lack. Private approvers may offer more flexibility and responsiveness, and negotiate their fees directly with you.
  • Fees are not fixed nationally. Councils base theirs on the type of work and floor area, so get written quotes from both routes before choosing.
  • Whichever route you pick, keep the completion certificate. You may need it when you sell.

Table of Contents

What “approved inspector” means now

If you are searching for “approved inspector”, you are probably reading older advice or a builder’s quote that still uses the old wording. The Building Safety Act 2022 replaced references to approved inspectors with registered building control approvers, and the relevant amendments came into force on 6 April 2024 in England and Wales.

Two practical consequences follow:

  • The old register run by the Construction Industry Council is gone. Government guidance on CICAIR says the Building Safety Regulator now oversees all building control bodies, local authorities and private approvers alike.
  • Building control is now a regulated activity. According to Homebuilding’s comparison of the two routes, RBCAs must use registered building inspectors to carry it out.

The government’s own impact assessment says the reforms were meant to improve professional competence and increase oversight through new registration requirements for building inspectors. So if someone quotes you for an “approved inspector” today, ask whether they are a registered building control approver. That is the status that matters.

The same impact assessment notes that higher-risk buildings must now go through the Building Safety Regulator, with no private option. That affects tall residential blocks, not a house extension.

What each route actually does

The job is the same on paper: check that your design meets the building regulations, inspect the work as it goes up, and confirm at the end that it complies. GOV.UK explains that for work that is not a higher-risk building, you can seek approval from your local council or from a private registered building control approver.

The council route

You apply to the council, usually through the Planning Portal. The council’s building control team checks your plans, visits at key stages and issues the completion certificate. Councils are a long-standing, non-profit, impartial public body. Homebuilding’s article describes this as part of their appeal, alongside well-defined and predictable processes that may reassure first-time builders.

Inspector checking a rear extension wall junction

The private route

You appoint a registered approver, who tells the local authority about the work through an initial notice. Once an initial notice is accepted, responsibility for plan checking and site inspections is formally placed on the private approver, as the Local Government Association’s briefing sets out. That briefing dates from 2017 and uses the old terminology, but the principle of handing over responsibility remains the same.

Council vs private building control at a glance

Factor Council building control Private RBCA (formerly approved inspector)
Who appoints them You apply to your local council You choose and appoint the approver
Fees Based on the council’s costs: type of work, inspections, floor area Negotiated directly with you
Flexibility Predictable, well-defined processes May be more flexible and responsive
Enforcement powers Yes, as the statutory enforcement body No, must hand over to the council if a compliance issue cannot be resolved
Oversight Building Safety Regulator Building Safety Regulator
Local knowledge Know their own area May not be based locally
Paperwork route Full plans or building notice Initial notice, with the approver managing checks

The enforcement row is the one many homeowners miss. Homebuilding reports that local authorities act as the statutory enforcement body and have powers that private approvers do not. If a private approver cannot resolve a compliance issue, they must hand the project to the local authority.

For most well-planned extensions that never happens. It is still the main structural difference between the two routes, and it is worth knowing before you sign.

How fees compare

There is no national price list. GOV.UK states that council fees are based on their costs and depend on the type of work, site inspections, number of dwellings and total floor area. Private approvers negotiate fees directly with the homeowner.

So your two numbers come from two different logic systems: a published council scale on one side, and a quote that reflects the approver’s own pricing and workload on the other.

Some councils say they are cheaper. Swindon Borough Council, for example, says its fees are usually 10% to 20% cheaper than approved inspectors, depending on the inspector. Swindon’s own guidance for homeowners positions its service as independent and cost-effective. That is one council’s statement about its own area, not a rule for England. Your council may price differently.

When you compare, check that each quote covers the same things:

  • plan checking
  • all site inspections through to completion
  • the completion certificate
  • any re-inspections or extra visits

A lower headline fee that excludes inspections is not cheaper. Fees are separate from planning fees, which work on a different basis. If you are budgeting for the whole project, our guide to planning fees for an extension covers that side, and our piece on structural engineer fees covers another cost that building control will expect to see supported by calculations.

Speed and flexibility

This is where opinions differ most. Homebuilding’s analysis says private RBCAs may offer greater flexibility and responsiveness than local authorities, while councils have predictable processes. Its author suggests councils can sometimes be perceived as less flexible.

Notice the hedging: “may” and “perceived”. Neither route guarantees faster inspections. Homeowners in online forums report both experiences: councils that inspect the same day and private inspectors who are slow to arrive, and the reverse. The sensible approach is to treat speed as something to verify, not assume:

  • Ask each candidate how quickly they normally inspect after you give notice.
  • Ask where the inspector is based, as a distant inspector may take longer to reach your site.
  • Ask who you will actually deal with, and how you reach them.
  • Ask how they handle a disagreement about a detail, for example a structural point.

Answers to those four questions will tell you more than any general claim about private versus public.

How the application works

The route you choose changes the paperwork.

With the council

You choose between two types of application, as GOV.UK explains:

  • Full plans: the most thorough option, with a more detailed review of your proposals before construction begins.
  • Building notice: generally suitable for smaller projects. It lets work start 2 days after submission, but there is no upfront plan approval.

A building notice can feel faster, but the review happens on site, which can mean costly changes if something does not comply. We compare them in detail in Full Plans vs Building Notice.

With a private approver

You appoint the approver, who submits an initial notice to the council. From then on, the approver is responsible for plan checking and inspections. You do not run a parallel council application.

At the end

Whoever checks the work, you want a completion certificate. GOV.UK guidance on building work notes that a certificate of compliance may be important when selling your home. Our guide to getting a completion certificate for an extension walks through what to expect.

Which should you choose for a rear extension?

Neither route is wrong. Both are regulated, and both can sign off a well-built extension. Use these criteria:

  1. Price you can compare: get a written quote from each route that lists what is included.
  2. Your project’s complexity: if you are building something unusual, or you expect questions on structure, a responsive inspector who engages early helps. A council’s predictable process helps if you want clarity on what will happen at each stage.
  3. Your experience: first-time builders may value the structure of the council process, which Homebuilding highlights as reassuring.
  4. Your tolerance for escalation risk: the council’s enforcement powers and the private approver’s duty to hand over unresolved issues mean that, in a dispute, the council ends up as the decision-maker either way.
  5. Who coordinates it: if your builder manages building control for you, ask which route they use and why.

One more point. A tradesperson registered with a Competent Person Scheme can self-certify certain work, so separate building control approval may not be needed for that work. This applies to specific installations, not to the structure of a rear extension as a whole, so do not assume it covers your project. Where it does not, contact a building control body before you start.

Our view on council vs private

We build single-storey rear extensions, and building control sits in the middle of every one of them. Here is how we think about it.

The choice is less dramatic than the search results suggest. Most disputes we hear about come from vague scope, not from the type of body doing the inspecting. A clear set of drawings, structural calculations that match what is built, and a builder who knows what the inspector will look for do more for your timeline than the council-or-private decision.

We would also say the paperwork is where homeowners lose time. Planning, building regulations, structural design and construction are usually handled by separate people who do not talk to each other. Our approach is to keep design, planning, building control management and construction in one in-house team, so the person drawing the extension already knows what the inspector will ask.

If you are choosing on your own, do not pick on price alone. Pick on what is included, how quickly they respond to you, and whether you understand what they will check at each stage. Then keep every certificate.

— Esskay

How we handle building control on your extension

When you book a single-storey rear extension with The Extension Works, building control is part of the managed service, alongside design, planning permission handling (including Permitted Development and prior-approval routes), architectural plans, structural calculations and construction. You get a fixed VAT-inclusive price, a dedicated team, a 12-month workmanship warranty and no sales visits.

The Extension Works

You can see how your extension would look and what it would cost with our instant extension quote tool. Booking is by a one-off booking fee of £499. If you want to understand the planning side first, read our rear extension planning guide.

Questions to ask before you appoint anyone

Whether you go to the council or a private approver, ask for answers in writing:

  • Are you a registered building control body, and who regulates you?
  • What exactly does your fee cover, including re-inspections?
  • How many working days’ notice do you need for an inspection?
  • Which stages will you inspect, for example foundations, drainage, structure and insulation?
  • What happens if you and the builder disagree on a detail?
  • When and how will I receive the completion certificate?

A good body answers these plainly. Hesitation tells you something.

FAQ

Is an approved inspector the same as a registered building control approver?

In practice, yes. The Building Safety Act 2022 replaced the term “approved inspector” with “registered building control approver”, effective 6 April 2024 in England and Wales. The old CICAIR register no longer exists, and the Building Safety Regulator now oversees these providers.

Is private building control cheaper than the council?

Not necessarily. Council fees depend on the type of work, inspections and floor area, while private approvers negotiate directly with you. Some councils say they are cheaper, but others may not be. Compare written quotes that cover the same inspections and certificate.

Can I switch from the council to a private approver, or the other way round?

We cannot confirm the rules for switching from the sources we have used here. Ask both bodies directly before you start, because the initial notice and any council application affect who is responsible for the work. Do not begin work until you know which body is in charge.

Do I need building control for every extension?

Work that needs approval and is not carried out by a Competent Person Scheme installer needs a building control body before you start, according to GOV.UK. A rear extension generally falls into that category, so plan for it from the start. Your council can confirm for your specific project.

Does the rule apply in Scotland and Northern Ireland?

No. Scotland and Northern Ireland have different building control rules. The choice between a council and a private registered approver described here applies to England and Wales for work that is not a higher-risk building.

Sources