Building control is the statutory system that checks building work meets minimum standards for structural safety, fire protection, energy efficiency, and health. Building regulations set those standards; a building control body — either your local authority team or a registered private approver — verifies that your project meets them through plan checks, on-site inspections, and a final Completion Certificate.
What building control officers actually do:
- Check submitted plans against the Approved Documents before work starts
- Carry out on-site inspections at critical stages (foundations, drainage, structure, insulation, fire-stopping)
- Issue a Completion Certificate when the finished work complies
The Completion Certificate is the document that matters most to your solicitor, mortgage lender, and insurer. Without it, selling or remortgaging a property that has had notifiable building work becomes significantly harder. Contact a building control body before work starts, not after.
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Table of Contents
- Which projects normally need building control approval?
- How do you get building control approval?
- What do inspectors check at each stage?
- What does building control cost, and how long does it take?
- What are the risks of skipping building control?
- How to work with your builder on building control
- Where to find the official guidance and Approved Documents
- Key takeaways
- Why building control matters more than most homeowners realise
- Complete-Property-Solutions takes care of building control for you
Which projects normally need building control approval?
Most common home improvement projects require approval. The list is longer than many homeowners expect:
- House extensions (single-storey, double-storey, wraparound, kitchen extensions)
- Garage conversions to habitable rooms
- Structural wall removals and RSJ steel installations
- Loft conversions
- Conservatory roof replacements or upgrades to a solid tiled or insulated roof
- New or altered drainage
- Changes to insulation, heating systems, or electrical circuits
Conservatories and porches can be exempt if they are built at ground level, under 30 m² in floor area, thermally separated from the main dwelling, and glazed to safety standards. The so-called “2.5 metre rule” is a common misnomer — the actual threshold is the 30 m² floor area combined with thermal separation. Upgrade that conservatory roof to a solid UltraRoof system and the thermal separation no longer applies, so full approval is required.
Some trades can self-certify under Competent Person Schemes — a FENSA-registered glazing installer or a Part P-registered electrician, for example. They notify the relevant authority on your behalf. Structural work, extensions, and conversions fall outside those schemes entirely.
Pro Tip: Homeowners frequently assume a small rear extension or a garage conversion is exempt. It almost never is. If in doubt, call your local authority building control team before a single brick is laid.
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How do you get building control approval?
Three routes are available:
- Full plans submission. You submit detailed drawings and specifications before work starts. The building control body checks and approves the plans, then inspects on site at agreed stages. This is the most thorough route and the one most experienced builders recommend for extensions and conversions.
- Building notice. No plans are submitted in advance. Work proceeds and the inspector visits on site. Faster to start, but any non-compliance discovered on site must be corrected immediately, with no prior plan approval to fall back on.
- Competent Person Scheme self-certification. The registered installer notifies the scheme, which registers the work. Only available for specified trades and works.
You can use either your local authority building control (LABC) team or a private Registered Building Control Approver. Local authority teams hold formal enforcement powers under the Building Act 1984 and bring local knowledge of ground conditions, drainage, and historic property details — particularly useful in older housing stock across Warrington, St Helens, and Wigan. Private approvers can sometimes offer more flexible scheduling.
Your builder or designer typically submits the application, but the legal responsibility for compliance rests with you as the homeowner.
Date to note: From 1 October 2026, certain residential building control applications may be subject to a Building Safety Levy. If your project spans that date, confirm with your building control body whether the levy applies.
What do inspectors check at each stage?
- Foundations and trenching — depth, width, and bearing capacity; must be inspected before concrete is poured
- Drainage — pipe runs, gradients, and connections; must be visible before backfilling
- Damp-proof course (DPC) — position and continuity at wall base
- Structural steel (RSJs) — bearing lengths, padstones, and fire protection before plastering
- First-fix services — electrical, plumbing, and ventilation routes
- Insulation and airtightness — U-values and continuity before boarding
- Fire-stopping and means of escape — particularly critical in loft conversions
- Final inspection — all works complete; certificate issued if compliant
Missing an inspection stage is costly. Covering foundations or structural steelwork before the inspector has seen them can mean digging up concrete or removing plasterboard to allow retrospective inspection. Your builder should book each stage in advance and never cover work without sign-off.
Pro Tip: Ask your builder to share the inspection booking confirmation with you at each stage. A simple message or email gives you a paper trail and confirms the work is progressing compliantly.
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What does building control cost, and how long does it take?
Fees vary by local authority and project type. Realistic ranges for common domestic projects:
| Project | Typical fee range | Typical timescale to Completion Certificate |
|---|---|---|
| Single-storey extension | Fees vary by local authority | Completion timescales vary |
| Double-storey extension | Fees vary by local authority | Completion timescales vary |
| Garage conversion | Fees vary by local authority | Completion timescales vary |
| Loft conversion | Fees vary by local authority | Completion timescales vary |
| Regularisation (past work) | Fees vary by local authority | Completion timescales vary |
Private approvers may charge differently. Fees are set locally, so always confirm with your chosen building control body before budgeting.
Delays most commonly arise from incomplete plan submissions, missed inspection stages, or planning issues discovered mid-build. Submitting full plans with detailed drawings, and using a builder who books inspections proactively, keeps projects on track.
What are the risks of skipping building control?
The consequences are serious and long-lasting:
- Enforcement notices requiring you to alter or demolish non-compliant work
- Refusal of a Completion Certificate, leaving the property with an unresolved compliance gap
- Mortgage lenders and conveyancers routinely flag missing certificates, delaying or blocking sales
- Buildings insurance may be void or disputed if undisclosed unauthorised work is involved
- Possible prosecution under the Building Act 1984
If previous owners carried out work without approval, a Regularisation application invites the local authority to inspect the past work. If it fails current standards, remediation is required before a certificate can be issued. You cannot simply purchase a retrospective certificate — the work must be shown to comply.
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How to work with your builder on building control
Responsibilities need to be clear from the outset. Before signing a contract, ask:
- Who submits the building control application, and who pays the fee?
- Which Competent Person Schemes are you registered with, and which works do those cover?
- Who books each inspection stage, and how will you confirm bookings with me?
- What happens if an inspection is missed or work needs to be corrected?
- Will you involve the building control inspector at the design stage?
Local authority surveyors in Warrington, St Helens, and Wigan understand local ground conditions and drainage patterns that affect compliance on older properties. An experienced builder who already has a working relationship with the local team can reduce delays significantly. Verify exactly which works your builder can self-certify and insist on formal building control for everything else.
Where to find the official guidance and Approved Documents
The Approved Documents are the technical standards that underpin every building regulations decision. They cover structure (Part A), fire safety (Part B), drainage (Part H), insulation (Part L), and more. Reading the relevant document before your project starts helps you understand what the inspector will be checking.
Key resources:
- Planning Portal — explains the difference between building regulations and planning permission, and links to application guidance
- GOV.UK building regulations approval — the definitive guide to when approval is needed and the three application routes
- LABC (Local Authority Building Control) — guidance on local authority teams, enforcement, and Regularisation
- Building Control Portal — search for registered private approvers and track applications
“Building Control is primarily about ensuring building work complies with minimum standards for health and safety of persons in and around buildings, conservation of fuel and power, and accessibility.” — City of London Building Control
For site-specific questions — unusual ground conditions, drainage constraints, or historic property details — contact your local authority building control team directly. They can advise before you commit to a design.
Key takeaways
Building control approval is a legal requirement for most home improvement projects, and the Completion Certificate it produces is the document that protects your investment at sale, remortgage, and insurance.
| Point | Details |
|---|---|
| Apply before work starts | Submit a full plans application or building notice before any construction begins. |
| Book every inspection stage | Never cover foundations, drainage, steelwork, or insulation before the inspector has signed off. |
| Get your Completion Certificate | Without it, selling or remortgaging a property with notifiable work becomes significantly harder. |
| Know what your builder self-certifies | Competent Person Schemes cover specific trades only; structural and extension work always needs formal approval. |
| Complete-Property-Solutions manages the process | Complete-Property-Solutions handles applications, inspection scheduling, and Completion Certificates for extensions and conversions across the North West. |
Why building control matters more than most homeowners realise
Most homeowners treat building control as an administrative hurdle. After more than 35 years of managing extensions and conversions across Warrington, St Helens, Wigan, and the wider North West, I’d argue the opposite is true. The inspection process is the single most reliable protection a homeowner has against a builder cutting corners on structural work, insulation, or fire safety.
The Completion Certificate is not just paperwork. It is the evidence your solicitor, lender, and insurer need to confirm the work was done properly. Projects that skip inspections or rush through the process often surface problems years later, at exactly the wrong moment — during a sale or a remortgage. Involving the building control inspector at the design stage, rather than treating them as an obstacle, consistently produces better outcomes and fewer costly surprises on site.
Complete-Property-Solutions takes care of building control for you
Managing building control alongside a live construction project takes experience, organisation, and good working relationships with local authority teams. Complete-Property-Solutions handles the full process for homeowners across Warrington, St Helens, Wigan, Great Sankey, Penketh, Culcheth, Lowton, Rainhill, and Haydock — from submitting the application and coordinating every inspection stage through to securing your Completion Certificate.
Before and after transformation of a garage conversion with a new first-floor extension, completed on Liverpool Road in Great Sankey.
Whether you are planning a house extension, a garage conversion, or a conservatory roof replacement, we manage the compliance side so you do not have to. Get in touch today for a transparent, fixed-price quotation and find out how we can take your project from design to Completion Certificate.
