What happens if you ignore building regulations? Experts explain the rules – and the potential cost of not following them

Understanding how to comply with the building regulations is key if you are making structural alterations to your home

Exterior of a kitchen extension, with sliding doors to the garden, and a large picture window
(Image credit: Future/ Chris Snook)

Renovating or extending your home usually involves some serious building work, and it's important that this work is completed properly. That's why it's crucial that you understand what the building regulations are, and when they apply.

These regulations are a set of guidance and standards that ensure that buildings are designed and constructed well to protect the health and safety of those who live in or near them. The regulations you need to follow will vary depending on the type of work you are undertaking. For example, the building regulations for an extension may be slightly different to loft conversion building regulations.

Even if your proposed project doesn't need planning permission, it's highly likely you will still need to comply with the building regs. We've spoken to multiple experts to help you understand when the building regulations apply, how you can apply, and the potential legal and financial consequences you could face if your project is non-compliant.

What are the building regulations?

Kitchen extension with fixed glazed roof, and bifold doors to the patio

(Image credit: Future/Talbot Photography)

The building regulations are a set of guidance documents that aim to ensure any building work is completed to a specified standard. They regulations are made up of multiple 'Approved Documents', with each document applying to a different area of construction.

Elli Kiely, Design & Innovation Director at HJK Construction, explains: 'Building regulations exist to ensure that all construction work meets essential standards for safety, health, energy efficiency, and accessibility. These rules help to protect homeowners, tenants, and future buyers by ensuring that buildings are structurally sound, properly insulated, and fire-safe, among other requirements.

'Building regulations are enforced by local authority building control departments or approved private inspectors. Before construction or major renovation work begins, approval must be sought, and inspections are carried out at key stages to ensure compliance.'

When do building regulations apply?

Bedroom in converted loft, with chair, large mirror, plant and large rooflight above the bed

(Image credit: Future PLC/ Dan Duchars)

Essentially, if you are making structural changes to your home, you will need to comply with the building regulations.

'Building regulation requirements cover a broad spectrum of home improvement works,' says property expert Harry Fenner. 'This can be from installing a new bathroom or kitchen with new plumbing, replacing a boiler or heating system, adding or changing electrical wiring, replacing windows or doors, altering load-bearing walls, adding extensions, converting a loft or basement, replacing roof coverings, and installing fixed air conditioning systems.'

The Approved Documents that make up the regulations apply to different areas of construction, and these are denoted with a specific letter. It might be that only a couple of these apply to your project. We've broken down below what each set of guidance refers to:

  • Approved Document A – Structure
  • Approved Document B – Fire Safety
  • Approved Document C – Site preparation, including contamination and damp
  • Approved Document D – Toxic substances
  • Approved Document E – Sound
  • Approved Document F – Ventilation
  • Approved Document G – Sanitation, hot water safety and water efficiency
  • Approved Document H – Drainage and waste disposal
  • Approved Document J – Combustion appliances and fuel storage systems
  • Approved Document K – On-site safety
  • Approved Document L – Conservation of Fuel and Power
  • Approved Document M – Access to an use of buildings
  • Approved Document O – Overheating
  • Approved Document P – Electrical safety
  • Approved Document Q – Security in dwellings
  • Approved Document S – Infrastructure for charging electric vehicles

Do outbuildings need building regs?

A garden office with glass doors and a seating area outside lined with lavender plants

(Image credit: Future PLC)

Whether outbuildings require building regulations compliance can be confusing. Property and construction expert Thomas Goodman from MyJobQuote.co.uk explains: 'Most buildings need building regulation applications. However, when it comes to outbuildings the regulations are a bit complicated.

'A small outbuilding of less than 15 square metres without sleeping accommodation, such as a summerhouse or shed, won’t require building regs,' says Thomas. 'A building that is between 15 square metres and 30 square metres without sleeping accommodation and which is more than one metre from any boundary or is made sustainably from non-combustible materials, will also not require building regulations approval.

When it comes to garages, it depends on what you are planning on building.

'A new attached garage typically requires building regulations approval,' says Thomas. 'An attached carport consisting of two open sides of less than 30 square metres won’t usually need approval.

'A detached garage, less than 30 square metres, won’t need building regs approval if the floor area is less than 15 square metres or between 15-30 square metres, with the garage being more than one metre from the boundary or constructed sustainably from noncombustible materials.'

Can I build without building regulations approval?

You can only build without Building Regulations approval if the work you are doing falls outside of their scope. But if your proposed work does require building regulations approval, then it is illegal to not comply with the guidance.

It's always best to check with your local authority's building control department to check whether your project needs approval before you start work to ensure you stay on the right side of the law.

What can happen if I build without Building Regulations approval?

If you have completed a project without building regs approval, then your first step should be to obtain a regularisation certificate, which is effectively a retrospective building regulations application.

Regularisation certificates can also only be issued for work completed after 11 November 1985. However, this will only be issued if the work is actually compliant. If it's not, then that's a different case.

Thomas Goodman explains: 'If something is built without being signed off by building control, the local authority will come and inspect the work. They may require you to change or even take down the construction if it fails to comply with building regs. This is typically done via an enforcement notice.

'The cost of putting the work right will fall to you as the homeowner, and you may also have to pay a fine. It’s also possible that legal proceedings will be taken against you for breaching building regulations.

'Without the completion certificate from building control, you may have difficulty selling your house in the future or need to drop the price to entice potential buyers.

'There is also a safety issue. Anything that is built without being inspected and signed off by a building control inspector may be unsafe and cause potential injury or worse.'

How do I apply for building regulations approval?

single storey kitchen extension with corner bifold doors to open the space up to the garden

(Image credit: Future/ Chris Snook)

If you are applying for building regulations approval through your local authority, then there are a couple of different routes, depending on the nature of your project.

For smaller projects, a Building Notice will usually be sufficient. This notifies the local building control department of the work, and acts as a promise that you will adhere to the guidance laid out in the regulations. Building control can let you know at which stages an officer needs to come and inspect the project. But if you don't comply with the guidance, you could face delays and extra costs as you'll need to put it right.

For more substantial work, a Full Plans application, which is a lot more thorough, is more suitable.

You will also need to submit a fee with your application, which will depend on the type of work you are carrying out. Check with you local building control department about which type of application to submit, and what fee will be required.

Who signs off on building regulations compliance?

If you have applied to your local authority, then it will be a local authority inspector who comes out to check and sign off on the work that has been undertaken.

However, you could also use a registered building control approver from a private building inspection company. They must be registered with the Building Safety Regulator.

Once the work is inspected and signed off, you should receive a certificate, which you should hold on to.

Depending on the alterations being made, some tradespeople and installers may be qualified to self-certify that their work complies with the building regs, and then report it to the local authority. This happens under the Competent Person Scheme, which can include window and door installers, electricians and gas engineers.

Using a Competent Person who is registered with the Department for Levelling Up, Housing and Communities- approved scheme means you won't need to submit an application to your local authority. They will submit the notification on your behalf, and will issue your certificate once the work is complete.

FAQs

Can you sell a house without building regs?

If you don't have building regs sign off, you could find you have issues selling your house. Buyers will want to see that any structural alterations have been done properly, and so without the certification may be put off entirely. You could also find that any offers made are lower than you want, as the potential buyers factor in the cost of any remedial work needed.

You could apply for a regularisation certificate, but you may have to fork out to make changes if the work is found to not be compliant.

Another option for a seller is to take out indemnity insurance.

Is building regs the same as planning permission?

Building regs are completely different to planning permission. Submitting a planning application is asking for permission to undertake your proposed work.

When it comes to building regulations, this is to ensure the work is completed to a satisfactory construction standard.

Depending on where you live and the alterations you want to make, you may need to apply for both planning permission and building regulations approval. If the work falls within the scope of Permitted Development, you won't need to apply for planning permission (although it might be worth applying for a Lawful Development Certificate), but you will still need building regulations approval.


While there is a lot to think about when it comes to making significant changes to your home, it's worth remembering that your proposed works may also require you to have a party wall agreement in place.

Sarah Handley
Section Editor – Renovation

Sarah Handley has been Ideal Home’s Section Editor for Renovation since September 2024, following three years of looking after the site's home finance content. She has been a journalist since 2007 and has worked for a range of titles including Homebuilding & Renovating, Real Homes, GoodtoKnow, The Money Edit and more.

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