House Extensions 101: Will My House Extension Cost Over the Odds in 2024?

You’ve heard the horror stories. They’re in the news and doing the rounds amongst your friends: Home improvements in 2024 are unaffordable.

It’s true that material costs for builders have been outpacing inflation over the last few years. The future of the economy looks bleak and builders need to keep up with a rising cost of living and an average mortgage rate that’s at its highest since 2009.

In 2020-2022, the pandemic and supply chain issues caused material costs to shoot up. That problem has mostly subsided, but in its place are other factors including Brexit, inflation and the war in Ukraine. All of these events play a part in increasing both material and labour costs, and therefore the cost of building an extension in the UK.

So while many of the horror stories are true, we’re here to bring you some good news: Homeowners in the UK aren’t letting the economy put them off improving their homes. And if an extension feels like the right move for your family, it’s still worth exploring.

After all, this is a home improvement that almost always generates more returns than it costs.

How much does a house extension cost in the UK in 2024?

Let us preface our answer here by saying the internet isn’t the best place to get an accurate estimate.


That’s because the real answer depends on how much you want to pay. And no home improvement blog can tell you that (not even us).

The final cost for both single-storey and double-storey extensions is based on your choice of finishes, design and complexities. In addition to the extra space itself, you’ll also have to account for the cost to fit kitchens and bathrooms, and any outbuildings, patios, driveways, windows and countless other elements.

Don’t forget those “soft costs”, too – that includes surveys, structural engineer and architect fees, planning application fees and council application costs, where relevant.

Let’s talk ballpark numbers.

A benchmark extension cost per m2 at the moment is around £2,000-£3,000 + VAT. Of course, so many factors affect the final cost, including your location, the method, materials and complexity of the build. So we’d advise taking these figures as a generalisation.

According to Checkatrade’s 2023 survey,  the average single-storey extension cost in the UK was £48,000 + VAT for a 20m2 extension, and the average double-storey extension cost was between £105,000 and £155,000 + VAT for a 60m2 addition.

Here are some costs to think about when putting a budget together: 

  • Structure (foundations, walls and roof)
  • Plumbing and heating
  • Electrics and lighting
  • Flooring (carpets, wood and tiles)
  • Decorating
  • Kitchen units
  • Windows and doors
  • Landscaping and exterior work
  • Insulation
  • Knocking down existing structures

Get a quote for an extension

How to make my extension add value?

Don’t let the numbers put you off an extension just yet. The cost of adding to a home is almost always outweighed by the returns it brings Nationwide research found that extending an average three-bedroom house could increase property value by up to 23%.

This rings true for additions all around the home. A carefully thought-out front extension, for example, creates huge curb appeal. At Heronlake, we excel at this, and have completely transformed homes with a strategic front extension. Remember: First impressions always count.

If you’re considering a rear extension, there are ways to create a seamless connection with the outdoors. This can become a unique escape area especially if your garden has mature trees… ideally not too close to the property! 

There are so many opportunities especially when you work with a builder who prioritises adding value throughout.

This quick guide points you to the best ways to boost your property’s value:

  • An extra bedroom
  • An extra bathroom or en-suite
  • Open-plan kitchen extension, particularly if your current kitchen has limited space
  • Loft conversions
  • Bi-fold doors
  • Rooflights
  • Cladding

Is a small extension even worth it?

Short answer: Yes!

Small extensions can have a big impact. The cost of a small addition will, of course, be lower than a large, sprawling extension. The following tips can help you get the most out of a smaller extension:

  1. Convert an integral garage. Just keep parking in mind if you’re hoping to sell at some point. Some buyers could be put off if there’s nowhere else to park.
  2. Improve the layout and flow of your space by combining a small extension with a layout configuration – just like this home improvement project in [location].
  3. Plan your extension around your lifestyle and build in the things that matter to you, such as a dedicated utility room, an extra lounge or a bigger kitchen.
  4. Invite more natural light for a fresh, airy feel.

That said, If you’ve got the budget, go big. There are economies of scale to grab and you’ll usually end up getting better value for money.


Is it cheaper to build an extension or move house?

That all comes down to your location and what you want to achieve, but we gave our take on the move vs improve argument here.

We’ve noticed recently that interest rates and house prices, in general, are deterring people from relocating. So, despite the growing costs to build an extension, homeowners in the UK are often choosing to add to the space they already have, rather than up-sticks and move.

Moving house is famously expensive, stressful and time-consuming. Extending doesn’t have to be (as long as you work with the right people).

What’s the cheapest type of extension?

Whatever structure is built, groundworks remain a constant. They’re the foundation of a building and builders should never cut corners here. In other words, if you want to cut costs, focus on the above-ground elements.

To reduce building extension costs, consider opting for:

  • A small extension
  • A flat roof 
  • Rendering finish rather than brick or cladding
  • A concrete tile rather than a clay tile roof
  • Double doors over bi-fold or sliding doors
  • uPVC windows
  • An open-plan internal layout
  • An inexperienced builder (just kidding – never do that)

The best way to get an accurate home extension cost? Ask Heronlake

While it’s true that house extension costs are at a high, working with a value-driven builder means you can bring your idea to life in the knowledge that the work will add value to your property. Homeowners in the UK are still extending, because it’s still worth it.

The route to success here is to be realistic about your budget from the outset. Talk to an extension builder early on, who can help you make the smartest use of space before you jump into anything.

Contact Heronlake to book a free home visit and get a quote for your house extension.