Key facts at a glance
- LABC = council building control; approved inspector = private sector alternative
- Both issue legally equivalent completion/final certificates
- LABC fees: £400–£900 for a typical loft or extension in London
- Approved inspector fees: £500–£1,200 (often fixed-fee quotes)
- Approved inspectors typically review plans within 5–10 working days
- Only LABC can issue Regularisation Certificates for historic work
What is LABC (council building control)?
LABC stands for Local Authority Building Control. It is the building control department within your borough council. Every London borough has an LABC team responsible for checking that building work complies with the Building Regulations 2010 (as amended). When you submit a Full Plans application or a Building Notice to the council, the LABC team is who reviews your drawings, carries out site inspections during construction, and issues the Completion Certificate when the work is finished.
The LABC route has been the traditional building control pathway in England and Wales since building regulations were introduced. Council building control officers are employed by the local authority, and they carry statutory enforcement powers -- meaning they can serve enforcement notices and, in extreme cases, require the removal of non-compliant work.
In London, LABC teams vary significantly in size, responsiveness, and capacity. Some boroughs -- particularly those with high volumes of development like Tower Hamlets, Hackney, and Southwark -- have stretched LABC teams that can take several weeks to review submitted plans. Others, like Richmond or Sutton, tend to have shorter turnaround times due to lower application volumes.
The Full Plans application route
A Full Plans application is the most thorough LABC route. You submit detailed architectural and structural drawings before work starts. The LABC team reviews the plans against all applicable Parts of the Building Regulations and either approves them (with or without conditions), requests amendments, or rejects them. Plan approval is valid for three years.
The Building Notice route
A Building Notice is a simpler submission: you notify the council that you intend to carry out building work, and the council inspects as work progresses. No plans are reviewed upfront. This route is quicker to start but riskier -- if the inspector finds non-compliant work on site, you may need to demolish and rebuild at your own cost. Building Notices are not available for commercial buildings or buildings fronting a new street.
What is an approved inspector?
An approved inspector -- now formally called a "registered building control approver" under the Building Safety Act 2022 -- is a private-sector building control body that provides an alternative to council LABC. They are registered with the Building Safety Regulator (BSR, part of the Health and Safety Executive) and must meet rigorous competence and insurance requirements.
When you use an approved inspector, they submit an "Initial Notice" to the council, which transfers building control responsibility from the council to the inspector for the duration of the project. The approved inspector then reviews your drawings, carries out site inspections, and issues a "Final Certificate" when the work is complete. This Final Certificate is the legal equivalent of the council's Completion Certificate.
Major approved inspectors operating in London include Assent Building Control, NHBC (for new-build homes), Approved Design, Stroma, and Premier Guarantee. Many are national firms with local surveyors who know the London market well.
How the Initial Notice works
The Initial Notice is a legal document jointly signed by the approved inspector and the person carrying out the work (you or your builder). It is submitted to the local authority, which has 5 working days to accept or reject it. Once accepted, the council steps back and the approved inspector takes over building control functions. The council cannot charge you building control fees while an Initial Notice is in force.
LABC vs approved inspector: side-by-side comparison
| Factor | LABC (council) | Approved inspector (private) |
|---|---|---|
| Who they are | Council employees in the borough's building control dept | Private companies registered with the Building Safety Regulator |
| Application type | Full Plans application or Building Notice | Initial Notice (submitted to council, who step back) |
| Typical fees (London loft/extension) | £400–£900 | £500–£1,200 |
| Plan review speed | 5 weeks statutory target (often 4–8 weeks in London) | 5–10 working days (commercially motivated) |
| Certificate issued | Completion Certificate | Final Certificate (legally equivalent) |
| Enforcement powers | Yes -- statutory enforcement notices | No -- must refer enforcement to the council |
| Regularisation of historic work | Yes -- only LABC can issue Regularisation Certificates | No |
| Flexibility on inspections | Fixed schedule; can be hard to book short-notice inspections | More flexible; often next-day inspections available |
| Relationship with planning dept | Same council -- easy cross-referencing with planning conditions | Separate organisation -- no automatic planning liaison |
| Commercial motivation | Public service -- no profit motive but can be slow | Profit-driven -- incentivised to provide fast, customer-focused service |
Cost comparison in detail
Building control fees are split into two components: the plan-check fee (for reviewing your drawings) and the inspection fee (for site visits during construction). LABC typically charges these separately; approved inspectors usually quote a single all-inclusive fee.
| Project type | LABC fee range | Approved inspector fee range |
|---|---|---|
| Single-storey rear extension | £350–£600 | £450–£800 |
| Loft conversion (Velux or dormer) | £500–£800 | £600–£1,000 |
| Two-storey extension | £600–£900 | £700–£1,200 |
| Loft + extension combined | £700–£1,100 | £800–£1,400 |
| Structural alterations only | £250–£450 | £350–£600 |
Approved inspectors tend to be 15–30% more expensive than LABC for straightforward residential projects. However, the cost difference is often offset by the faster plan review (which means your builder can start sooner) and more flexible inspection scheduling (which reduces builder downtime waiting for inspections).
Building control fees are a small fraction of the total project cost. On a £50,000 loft conversion, the difference between LABC and an approved inspector is typically £100–£300. Speed and service quality should drive your decision, not the fee.
Speed comparison
This is where the approved inspector route has a clear advantage for most London projects.
LABC has a statutory target of 5 weeks to review a Full Plans application. In practice, many London boroughs take 4–8 weeks, and some regularly exceed this during busy periods. If the LABC team requests amendments, each revision can add another 2–3 weeks.
Approved inspectors, operating in a competitive market, typically review plans within 5–10 working days. Some offer express review services (2–3 working days) for an additional fee. The Initial Notice itself is accepted by the council within 5 working days in almost all cases.
On site, approved inspectors generally offer more flexible inspection booking. Many provide next-day or even same-day inspection slots. LABC departments in busy London boroughs sometimes have 3–5 day lead times for inspection bookings, which can slow down construction programmes.
The inspection process
Both LABC and approved inspectors carry out the same core inspections during construction. For a typical loft conversion or extension, you should expect inspections at these stages:
- Commencement -- notification that work has started
- Foundations/excavation -- before concrete is poured (extensions)
- Damp-proof course -- before backfilling (extensions)
- Structural steelwork -- before steels are concealed
- Floor joists -- before boarding over
- Insulation -- before plasterboarding (thermal and sound)
- Fire stopping and compartmentation -- before concealment
- Pre-plaster -- general check before finishes
- Final/completion -- when all work is finished, including drainage, electrics certificates, gas certificates, and ventilation commissioning
The quality of inspection is broadly similar. Both LABC officers and approved inspector surveyors are qualified building control professionals with experience in residential construction. The key difference is in accessibility and responsiveness -- approved inspectors are typically easier to reach by phone, quicker to schedule inspections, and more proactive about communicating issues.
When to use LABC (council building control)
- Simple, straightforward projects where speed is not critical and the lower fee is attractive.
- Projects with planning conditions that require building control and planning to work together. Using the same council simplifies cross-referencing.
- Regularisation of historic work. Only LABC can issue a Regularisation Certificate. If you have completed building work without building control sign-off and need retrospective approval, you must use the council.
- Projects near building control disputes. If there is any risk of enforcement or legal challenge, having the council as your building control body ensures there is no question about the legitimacy of the sign-off.
- Budget is very tight and the £100–£300 saving matters to your overall project finances.
When to use an approved inspector
- Speed is important. If your builder is ready to start and you need plans reviewed quickly, an approved inspector can turn this around in days rather than weeks.
- Complex projects where you want a named surveyor you can build a relationship with throughout the project, rather than dealing with whoever is on duty at the council.
- Commercial or mixed-use projects where the approved inspector has specialist expertise.
- Multi-site projects where you want consistency of building control across different borough boundaries (an approved inspector can operate anywhere in England).
- Inspection scheduling flexibility -- if your builder works on tight programmes and needs next-day inspections to keep the project moving.
Our recommendation
For most residential projects in London -- loft conversions, extensions, internal structural alterations -- either route works well. The choice often comes down to programme timing and personal preference.
If your project is straightforward and there is no rush to start, LABC is the economical choice. The council's building control team knows the local housing stock, has a relationship with the planning department, and the fees are lower.
If your builder is ready and you want to start quickly, or if the project is complex and you want a dedicated surveyor, an approved inspector is worth the modest premium. The faster plan review and more flexible inspections can save more in builder downtime than the additional fee.
At Architectural Drawings London, we prepare building regulations drawings to the same standard regardless of which building control route you choose. Our drawings are fully detailed with structural layouts, fire safety strategies, thermal calculations, and all the construction details that building control needs. We can recommend specific approved inspectors we have worked with successfully across London, or guide you through the LABC submission process. Our building regulations packages start from £1,225.
Frequently asked questions
Is a completion certificate from an approved inspector the same as one from the council?
Yes. A Final Certificate issued by a registered building control approver (approved inspector) is legally equivalent to a Completion Certificate issued by LABC (the council's building control department). Both confirm that the building work complies with the Building Regulations. Mortgage lenders and conveyancing solicitors accept both equally. The Final Certificate is registered with the local authority, so it appears on the property's building control records just like a council-issued certificate.
How much does building control cost in London?
Council building control (LABC) fees for a typical London loft conversion or extension range from £400 to £900, depending on the borough and project complexity. Approved inspector fees for the same project typically range from £500 to £1,200. Approved inspectors often provide a fixed-fee quote upfront, while council fees may be split between a plan-check fee and an inspection fee. Building control fees are separate from our drawing fees, which start from £1,225.
Can I switch from an approved inspector to the council mid-project?
Switching mid-project is possible but complicated. The approved inspector must formally cancel their Initial Notice, and the work then reverts to the local authority. The council may require re-inspection of completed work and charge additional fees. Switching the other direction -- from council to approved inspector -- is generally not possible once a Full Plans application has been submitted. It is best to choose your building control route before work starts and stick with it.
Do I need building control for a loft conversion?
Yes, without exception. All loft conversions require building regulations approval, regardless of whether they need planning permission. The conversion involves structural alterations (new floor joists, steelwork), fire safety upgrades (protected staircase, fire doors, interlinked smoke alarms), thermal insulation, and sound insulation to party walls. You must either submit a Full Plans application to the council or an Initial Notice through an approved inspector before work starts. See our loft conversion drawings service.
What happens if I do building work without building control sign-off?
Building work completed without building control approval creates problems when you sell. Buyers' solicitors and mortgage lenders will require evidence of compliance. You can apply for a Regularisation Certificate from the council (not available through approved inspectors), which involves the council inspecting the completed work and potentially requesting invasive investigations -- opening up walls, floors, and ceilings to check structural elements and fire stopping. Regularisation fees are typically 150% of the standard building control fee. It is always cheaper, faster, and less disruptive to get building control involved from the outset.