Building Control Inspections: What They Are and What to Expect

Planning permission often gets all the attention, but building control is arguably more important when it comes to making sure your home build is safe, structurally sound, and legally compliant. Yet many homeowners reach the end of a project without fully understanding what building control involves — or realise too late that the work wasn't signed off properly.

Here's a straightforward guide to what building control inspections are, why they matter, and what you should expect when building in Oxfordshire.

What Is Building Control?

Building control is the process by which your local authority (or an approved private inspector) verifies that building work complies with the Building Regulations. These regulations cover structural safety, fire safety, insulation and energy efficiency, drainage, ventilation, and electrical and plumbing installations.

Unlike planning permission — which is about whether something should be built — building control is about how it's built. The two are separate processes, and you typically need both.

Do You Always Need Building Control?

Not always, but most significant building works do require it. Extensions, loft conversions, garage conversions, structural alterations, new bathrooms and kitchens (in certain circumstances), and electrical rewires all typically require building regulations approval.

Some minor works — like replacing a like-for-like window in a non-exempt property — may be handled through a competent persons scheme (FENSA, for example) rather than a full building control application.

If you're unsure, your builder should be able to advise, or you can check directly with your local authority. In Oxfordshire, projects within Vale of White Horse (covering Abingdon, Wantage, Grove, and Faringdon) fall under one authority, while Oxford City and Cherwell (Banbury, Kidlington, Bicester) each have their own building control teams.

How Do You Apply?

There are two main routes. A Full Plans Application involves submitting detailed drawings for approval before work starts — the inspector reviews and approves (or requests amendments) upfront. This is the recommended route for major projects as it reduces the risk of being asked to redo work later.

A Building Notice is a shorter form submitted before work starts, without full drawings being approved in advance. It can be quicker to set up but relies more heavily on the inspector's visits during construction. It's generally only appropriate for simpler projects.

What Happens During Inspections?

Once work is underway, the building control officer (BCO) will carry out a series of visits at key stages of the build. The exact stages depend on the type of project, but for a typical extension or loft conversion you can expect inspections at:

Commencement — the start of work is notified, often the day before or on the day work begins.

Foundation excavation — before concrete is poured, so the ground conditions can be checked.

Concrete pour — to check the mix and depth.

Damp-proof course — before it's covered over.

Structural elements — steels, floor joists, roof structure — before they're enclosed.

Drains — before they're backfilled.

Insulation and air tightness — before plasterboarding.

Completion — a final inspection of the finished work.

It's the builder's responsibility to notify building control at each stage. Missing a stage can mean remedial work — for example, if foundations are poured before the inspector has signed them off.

The Completion Certificate

Once all inspections are passed, you receive a completion certificate. This is an important document: it confirms the work was carried out in compliance with building regulations. You'll need it if you ever sell your home — solicitors will ask for it during the conveyancing process.

If you buy a property where building work was carried out without a completion certificate, you may face difficulty selling it later, or need to take out indemnity insurance.

At Acute Homes, we manage the building control process from application through to completion certificate as part of our full project management service — for homeowners across Abingdon, Oxford, Witney, Carterton, Thame, and beyond.

Private Building Control Inspectors

As well as local authority building control, you can use an approved inspector (now called registered building control approvers). These are private companies that carry out the same function. They're sometimes faster than local authority teams and can offer more flexibility around inspection scheduling.

Either route results in a legally valid certificate. Your builder should be able to advise which is more appropriate for your project.

A Word of Caution

Be wary of any builder who suggests skipping building control to save time or money. Work carried out without the required approvals is technically illegal, can create serious issues when you sell, and may pose genuine safety risks. A reputable builder will always manage compliance properly — if a contractor tells you it's not necessary, get a second opinion.