Building Regulations Explained: What You Need to Know

A clear guide to building regulations in the UK - what they are, when they apply, and how they differ from planning permission.

Building regulations and planning permission are the two main approvals needed for building work in the UK - but they cover completely different things. Many homeowners confuse them, which can lead to costly mistakes. This guide explains what building regulations are, when they apply, and how to get approval.

What Are Building Regulations?

Building regulations are national standards that ensure buildings are safe, energy-efficient, and accessible. They cover the technical aspects of how a building is constructed - structure, fire safety, insulation, ventilation, drainage, electrics, and more.

They are set out in the Building Regulations 2010 (as amended) and are enforced by your local council's building control team or by an approved private inspector.

Building Regulations vs Planning Permission

These are entirely separate systems:

You may need planning permission, building regulations approval, both, or neither - depending on the work. For example, a small rear extension might be permitted development (no planning permission needed) but will still require building regulations approval. Conversely, demolishing an internal wall to create an open-plan room does not need planning permission but may need building regulations if the wall is load-bearing.

Read more about the differences in our guide to building regulations vs planning permission.

When Do Building Regulations Apply?

Building regulations apply to most building work, including:

• Extensions - all extensions require building regulations, whether or not planning permission is needed
• Loft conversions - structural alterations, fire safety, insulation, stairs
• Garage conversions - thermal insulation, ventilation, structural changes
• New buildings - houses, outbuildings over certain size thresholds
• Structural alterations - removing or altering load-bearing walls, chimney breasts
• Rewiring or new electrical circuits - particularly in kitchens and bathrooms
• New bathroom or kitchen plumbing - drainage connections, ventilation
• Replacement windows and doors - must meet thermal performance standards
• New heating systems - boilers, heat pumps, flues
• Changes of use - converting commercial premises to residential, for example

When Are Building Regulations NOT Required?

Some minor works are exempt:

• Outbuildings under 15 m² with no sleeping accommodation
• Outbuildings between 15-30 m² that are more than 1 metre from a boundary and are substantially non-combustible (or under 30 m² and single storey)
• Small porches under 30 m² (with conditions)
• Like-for-like repairs (replacing a broken roof tile with the same type)
• Minor internal alterations to non-structural walls
• Garden walls, fences, and gates under certain heights

How to Get Building Regulations Approval

There are two main routes:

1. Full Plans Application

You submit detailed plans and technical drawings to building control before starting work. The plans are checked for compliance, and you receive formal approval. This is the recommended route for most projects because:

• You know before you start that the design complies
• It reduces the risk of having to alter work mid-build
• It provides a clear record for mortgage lenders and solicitors

Full plans applications typically take 5-8 weeks to be assessed. The council will then inspect the work at key stages (foundations, damp-proof course, drainage, completion).

2. Building Notice

You notify building control that you intend to carry out work, and they inspect it as it progresses. No plans are submitted in advance. This route is quicker to start but riskier - if the inspector finds non-compliance during a site visit, you may need to redo work at your own cost.

Building notices are commonly used for smaller projects like boiler replacements or electrical work, where the scope is well-defined.

3. Competent Person Schemes

Certain types of work can be self-certified by installers registered with a competent person scheme. This includes:

• Gas installations (Gas Safe Register)
• Electrical work (NICEIC, NAPIT, ELECSA)
• Replacement windows (FENSA, CERTASS)
• Plumbing and heating (APHC, OFTEC)

When a competent person completes the work, they notify building control on your behalf and issue a certificate. You do not need to make a separate building regulations application.

Costs

Building regulations fees vary by council and by the type of work:

Private approved inspectors may charge differently - sometimes more for the initial assessment but with faster response times.

The Completion Certificate

When the work is finished and passes the final inspection, building control issues a completion certificate. This is a critical document - keep it safely. You will need it when selling the property, as solicitors and mortgage lenders check for completion certificates on any building work.

If you have had work done without a completion certificate (common with older alterations), you can apply for a regularisation certificate. This involves a retrospective inspection and will cost more than a standard application, but it resolves the compliance question.

What Happens If You Don't Comply?

If building work does not comply with building regulations:

• The council can serve an enforcement notice requiring you to alter or remove the non-compliant work
• In extreme cases, the council can carry out the work itself and charge you for it
• When selling, the absence of a completion certificate can delay or derail the sale
• Insurers may refuse claims related to non-compliant work

The enforcement time limit is generally 12 months from completion of the work for a prosecution, but there is no time limit on the council's power to require alteration of non-compliant work.