One of the biggest challenges of extending your home is navigating the laws, regulations, and planning permission processes. But don’t let this discourage you from creating your dream home. Here’s a useful guide to the most important considerations when it comes to house extension rules and adding on to your property from our design and build company in London. Keep in mind that our team can manage every aspect of your build, including technical guidance and applications for planning permission.

Is Extending Your Property the Right Move for You?

If you’ve been considering adding an extension to your house, the first thing to think about is whether it will increase its value and how much additional space the addition will contribute. The value rise may be significantly greater than the original spending for the expansion, depending on the quality of the extension and the location of your home. If it’s not, is the additional space worth the money? How do the expenses of upgrading to a larger home and moving compare? 

It’s a good idea to compare property valuations in your area and see what similar homes are selling for to get an idea of the short-term gain. Keep in mind that when you extend your home, you may stay in the space for 5 years or more, so consider how the area has increased in value over the last 5-10 years. 

When you’re working with a design and build company like Plus Rooms, they can help you maximise returns on your extension by advising you on how to best extend your home within your budget. It’s also a good idea to look at past projects for inspiration, and use a home extension cost calculator to play around with different ideas.

Can I Build a House Extension Without Planning Permission?

Yes – but it does have to follow the limitations that we have set out below. Essentially, you have permitted development rights as a homeowner in the UK for house extensions and modifications that fall within these restrictions, but anything that exceeds the rules below will require planning permission.

These rules also apply only to houses – not flats, maisonettes, or properties that require additional planning permission such as historical listed buildings.

What Are the Rules When Planning a Single-storey House Extension?

When extending a single-storey home, the general planning permission rules are:

  • The extension’s height is limited to four meters
  • A single-story rear addition cannot extend more than four meters past the initial property’s back wall.
  • With the clear exception of a conservatory, the materials used must match the present design of the home.
  • House extension regulations state that extensions that are in front of side elevations or elevations that face a roadway are not permitted. This means that you would need planning approval if you wanted to extend your home toward the main road.
  • Exterior cladding is not permitted on buildings located on protected ground.
  • With an extension or any other form of construction, you can only enclose half of the land that was surrounding the initial house.

You can see our single-storey home extensions here for inspiration.

What Are the Rules When Planning a Double-storey House Extension?

For double-storey house extensions, the rules are as follows:

  • Extensions over three meters beyond the house’s rear wall are prohibited.
  • The roof pitch must fit the existing property or be as near to it as possible.
  • If you are within two metres of the boundary, the extension’s roof cannot be higher than three meters.
  • According to the house extension rules, the extension’s exterior must be constructed with materials that appear similar to those of the house.
  • A minimum of seven meters must separate the expansion from the back boundaries.
  • Any elevated platforms, verandas, or balconies require planning approval.
  • Any upper-floor window in a “side elevation” must be non-opening and obscure-glazed.
  • The ridge and overhang cannot rise higher than the current structure.

You can see our double-storey home extensions here for inspiration.

Side and Rear Extensions

If you want to build a side extension, rear extension, or a side and rear house extension, the rules are as follows:

  • On designated land, side extensions are not allowed.
  • The height of a single-story side addition cannot be greater than four meters.
  • The width of the extension cannot be greater than half the width of the initial property.
  • The maximum length of a single-story addition to the rear is four meters.

Other Considerations, Rules and Regulations When Planning a House Extension

When a project has planning approval, it follows that it must adhere to construction rules and building codes, which serve as the minimal requirement for all building planning, construction, and alterations. For building extension rules and regulations approval, you can submit an application to any local building control department or authorised inspector. Building extension rules and regulations must apply to everything that involves construction activity, including:

  • Structure construction or expansion.
  • The altering or reinforcement of a building’s foundation.
  • Work influencing a building’s thermal components, energy situation, or energy efficiency.
  • An undertaking for modification.

Do I Need Permission When Planning a House Extension?

While you can make a lot of improvements and developments to your house with permitted development rights without getting the planning office’s permission, it is always best to have all your bases covered. It is essential to know whether your house has permitted development rights, if there are additional planning conditions, or if your extension will exceed permitted development rights. Building regulatory requirements must be taken into account when applying for planning approval and there are restrictions on what can be done without seeking permission. 

At Plus Rooms, were well aware of what you can and can’t do when building an extension and have a professional team that is available to advise you. 

How Can I Build an Extension Without Planning Permission?

As long as you are within permitted development rules, you can build an extension without planning permission. 

However, if you’re asking how far you can go without getting planning approval, it depends on the kind of house you have. Changes to permitted building approval came into effect in 2020 as a result of the pandemic’s persistence and the need for more room among many homeowners to conduct their daily activities.

The changes implemented the larger home extension scheme, otherwise known as prior approval. This is a 28-day application to find out how far you can expand without planning approval based on your neighbours’ lack of objection. However, keep in mind that many variables, including height, ground level, elevated platforms, the original, as-built property size, and the location of border walls, can cause your expansion to fall under public discretion. With this in mind, you must exercise caution. Contact our knowledgeable staff right away if you have questions about how house extension regulations work and staying on the right side of the law to avoid delays and costly penalties on your house extension.

Read more about building regulations in the UK.

Get Your Dream House Extension with London’s Leading Design and Build Company

Plus Rooms is a full-service provider for all types of home extensions in the greater London area, including loft, kitchen, and kitchen diner extensions. We’ll work with you through the entire process, from designing your extension and managing planning permission to building the project and ensuring it is completed to your satisfaction. Be inspired by our kitchen extension design ideas, see reviews from past clients, and to start the journey towards your dream home.