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What is the UK Average Extension Cost in June 2026?

As of June 2026, homeowners across the UK are facing a critical decision: whether to extend their current properties or sell up and move. With the latest Office for National Statistics (ONS) May 2026 local house price breakdowns highlighting stark regional price gaps, notably in areas like Solihull, the financial calculus is changing dramatically.

If you’re considering an extension, getting clarity on exact costs is essential before you dive into quotes or start knocking down walls. Thanks to updated data from MyJobQuote (updated 24 June 2026) and contractor reviews on Checkatrade, plus insights from planning tools like the Solihull Council pre-application enquiry system, this article breaks down the UK average extension cost, what drives the big regional differences, and what hidden expenses you shouldn’t forget.

UK Average Extension Cost in 2026: The £52,000 Baseline

Let’s cut straight to it. The current UK average extension cost stands around £52,000. This figure isn’t plucked from thin air but reflects compilation of recent quotes via MyJobQuote, cross-referenced with verified contractor data on Checkatrade, and sanity-checked against typical square metre rates for extensions in both urban and suburban settings.

However, this £52,000 figure should be seen as a budget solihullobserver.co.uk baseline, with the actual cost heavily influenced by:

  • Extension size and design (single-storey vs two-storey)
  • Local planning constraints and conservation area regulations
  • Material choices and contractor type (trade specialists vs general builders)
  • Site-specific factors like garden access, ground condition and property age
  • Whether VAT and contingency costs are explicitly included

Before we unpack the breakdown, keep in mind that any serious budgeting must include a minimum 10–15% contingency. Surprises happen on-site, and if you don’t plan for them, your stress – and bills – will skyrocket.

Extension Costs by Size and Type

Size is usually the most tangible driver of extension costs. Contractors and estimators like myself always start by calculating a reliable cost per square metre (m²). Here’s how the current averages stack up in June 2026:

Extension Type Typical Size Range (m²) Average Cost per m² Estimated Total Cost Range Single-storey rear extension 15 – 30 m² £2,200 – £2,800 £33,000 – £84,000 Two-storey side or rear extension 30 – 60 m² £2,500 – £3,200 £75,000 – £192,000

The wider cost range is not just about geographic location – Solihull is a prime example of dramatic price variation. According to the ONS May 2026 local house price breakdowns, the average house price in Solihull has surged by 10% year-on-year, far outstripping many neighbouring boroughs. This surge is making local homeowners opt to extend rather than move as the jump in house prices and stamp duty costs makes moving less attractive financially.

Single-storey Extensions

Single-storey extensions are typically used for kitchen-diners and family rooms, with costs driven by foundation depth, roof structure (flat or pitched), and internal finishes.

Expect to pay the lower end of the £2,200 to £2,800 per m² range if you keep things straightforward with a flat roof and mid-range finishes. Switching to a pitched roof or adding bi-fold doors and skylights can push you towards the upper end.

Two-storey Extensions

Two-storey extensions roughly double space but often cost disproportionately more due to:

  • Additional structural work
  • Matching existing brickwork and rooflines
  • Planning permissions and neighbour consultations

Per square metre costs rise accordingly, so factoring in £2,500 to £3,200 per m² is prudent if your budget allows for quality and longevity.

Planning and Legal Checks: Never Skip These!

The days of simply knocking up an extension without council eyes on the job have gone. Whether you live in Solihull or anywhere else in the UK, using tools like the Solihull Council pre-application enquiry facility can save you months of delays and unexpected redesign costs.

Before you commit, do these checks:

  1. Pre-application Enquiry: Submit your extension plans early to get initial feedback on planning viability.
  2. Full Planning Application: Necessary for two-storey and larger extensions.
  3. Permitted Development Checks: Many single-storey extensions within allowed size limits might not require full planning permissions but must comply with height and boundary rules.

Ignoring these steps can result in costly forced removals or redesigns later down the line. The Solihull planning application portal is a good starting point to understand what’s permissible for your property.

Extending vs Moving: The Hidden True Costs

The big driver behind the current extension boom is the soaring house prices reported by the ONS in certain regions like Solihull. Moving seems like a straightforward way to gain extra space, but the total costs paint a different picture:

  • Stamp Duty: In many cases, stamp duty or equivalent property transaction taxes can add 3–5% or more of the purchase price. In Solihull’s current market, this can easily equal £15,000–£25,000 on average homes.
  • Estate Agent and Legal Fees: These can reach £3,000–£5,000 depending on property price and complexity.
  • Removal Costs: £1,000–£3,000 based on volume and distance.
  • Mortgage and Survey Fees: Even modest fees add £1,000+.

All together, moving can cost upwards of £25,000–£35,000 without adding a square metre of space. Contrast that with investing £50,000+ to physically increase your home’s footprints, and the financial logic to extend rather than move becomes clear.

What People Forget to Budget For

Having run hundreds of estimates, I can tell you exactly where most homeowners underestimate their extension budgets:

  • VAT: Always confirm if your quotes include VAT (currently 20%). Many DIY articles gloss over this vital point, but it can add thousands quickly.
  • Builder Contingency: At least 10% of the build cost for unforeseen site issues or minor changes in scope.
  • Design and Survey Fees: Architect drawings, structural engineer reports, and party wall agreements can cumulatively add £3,000–£7,000.
  • Internal Decoration and Services: Extensions aren’t just shells. Heating, electrical rewiring, plumbing and finishes add significant costs.
  • Temporary Accommodation or Disruption: Planning for meals out, dust control, or even staying away for short periods is often overlooked.

Using platforms like MyJobQuote (updated 24 June 2026) to source multiple detailed, VAT-inclusive quotes with clear contingencies is the best way to build a realistic financial picture before signing contracts.

Final Thoughts: Is Extending Worth It?

In 2026’s UK property climate, with the ONS local pricing data revealing dynamic regional housing value swings and Solihull prices pushing many residents to extend rather than move, understanding the full spectrum of extension costs is crucial.

The average £52,000 extension budget baseline provides a starting point, but expect to tailor your budget depending on size, type, and location—and don’t forget your planning permissions or contingencies.

Finally, weigh the extension costs against the often overlooked expenses of moving. For many, the path to extra space and long-term value lies not in the costly shuffle of property transactions but in carefully planned, professionally executed extensions.

For more tailored quotes and to browse verified contractor profiles, visit MyJobQuote and Checkatrade. Don’t forget to check your local council’s planning pre-application systems—Solihull’s portal is a great model for proactive homeowners.