When it comes to creating more space in your home, a cleverly planned extension can truly change the way you live, adding value and space to your home and lifestyle. But one of the earliest choices that you will have to make is whether you will choose to have a side extension or a rear extension. Different things will come into play here, from the structure of the property, what you can afford to your planning permission, and the type of space that you need.

In this guide, we will break down the pros and cons of each to help you determine which type of extension is most suitable for your home.

Understanding the Basics

Side Extension:

Usually erected along the side passage (the space between your house and the boundary wall), side extensions are more common in semi-detached and detached properties. Mutually supportive extensions are a frequent feature in terraced houses, which make up most of the stock in the study site, with side return extensions filling in redundant alley space.

Rear Extension:

It is an extension that is built onto the rear of the property and is popular in both detached and terraced homes. They can be anything from a small bump-out to a big open-plan space that flows out onto the garden.

Pros of a Side Extension

Maximising Dead Space: Great for applying in thin side streets that are basically useless.

Good for Kitchens or Utility Rooms: A side extension can expand the back of the home to make way for a larger kitchen, utility room, or open-plan living space.

Natural light: Skylights and glass ceilings can add light to what was once a dark area of the house.

Minimal Garden Upheaval: Your backyard is essentially untouched.

Cons of a Side Extension

Narrow Width: It has a narrow design and space, which presents a tougher design and layout.

Structural complexity: An unobtrusive side return will often involve a relatively complex structural solution, which will increase the amount of time and money you need to spend on your work.

May Need Planning Permission: Especially if the extension dramatically alters the exterior of the property or is near a neighbor’s boundary.

Pros of a Rear Extension

  • Larger Space: Rear extensions offer more flexibility in terms of size, allowing for full-width kitchen-diners or extended lounges.
  • Indoor-Outdoor Living: These extensions often connect seamlessly with gardens, making them perfect for open-plan layouts and entertaining spaces.

Permitted Development Friendly: Rear extensions may fall under permitted development rights, especially single-storey builds, depending on the size.

Cons of a Rear Extension

  • Reduces Garden Space: Your garden size will shrink, which may affect your outdoor lifestyle or future resale appeal.
  • May Affect Neighbours’ Light Access: Rear extensions can potentially block natural light for neighbouring homes, which could complicate planning approval.
  • Longer Build Time: Larger projects typically require more time and resources.

Which House Extension is Best?

Choosing between a side extension vs rear extension depends on your goals, property type, and budget:

  • If you want to retain your garden and improve your kitchen flow, a side extension might be ideal.
  • If you’re aiming for significant internal space and a seamless indoor-outdoor connection, a rear extension may be the better fit.

In the UK, combining both options into an L-shaped wraparound extension is also common for those seeking maximum impact.

Rear Extension Cost UK

Cost is always a big consideration. On average:

  • Rear extension cost UK ranges from £1,800 to £3,000 per square metre, depending on materials, design complexity, and location.
  • Side extensions can be slightly more affordable due to their typically smaller footprint, but this isn’t always the case.

Other cost factors include:

  • Planning permission and architect fees.
  • Structural changes and utility relocations.

Interior finishes and glazing choices.

Planning Permission and Regulations

Whether you choose a side or rear extension, UK regulations vary based on:

  • Property type (detached, semi-detached, terraced).
  • Extension size and proximity to boundaries.
  • Impact on neighbours.

Many extensions fall under permitted development rights, but it’s crucial to verify this with your local planning authority or hire a professional to manage approvals.

Final Thoughts

When deciding between a side or rear extension UK homeowners should consider space, function, budget, and long-term value. There’s no one-size-fits-all answer—but with proper planning, either option can dramatically enhance your home’s livability and market appeal.

Still unsure which way to go? JGB Services Ltd offers expert advice and comprehensive building services to help you decide, design, and build the perfect extension for your lifestyle.