How Much Does a Single Storey Extension Cost in Solihull? (2026 Guide)
A single storey extension is a single-level addition to your home, built at the rear, to the side, or wrapped around the side and rear. It’s the most common way homeowners in Solihull add space, whether that’s a bigger kitchen, a family room, or a home office, without the cost or disruption of building upwards. If you’re planning one for 2026, here’s what it actually costs, what affects the price, and how long you should expect it to take.
As FMB-registered builders based in Solihull with over 20 years’ experience, we put together this guide using the real figures we quote against, so you can budget accurately before you start getting quotes.
What affects the cost of a single storey extension
No two extensions cost exactly the same, because the price is driven by several factors specific to your project:
- Size and footprint – the larger the extension, the lower your cost per square metre tends to be, since fixed costs like groundwork setup and roofing labour are spread across more space.
- Extension format – a straightforward rear extension is usually the simplest and most cost-effective. A side-return extension often involves working in a tighter space. A wraparound extension (rear plus side) is the most complex and typically the most expensive, because it combines two junctions with the existing house.
- Groundworks and ground conditions – sloping gardens, poor soil, or the need for deeper foundations near trees or drains can add cost before the build even reaches ground level.
- Roof design – a flat roof is generally cheaper than a pitched or vaulted roof, but a pitched roof with rooflights can add valuable light and headroom.
- Glazing – bi-fold or sliding doors, roof lanterns, and larger glazed areas cost more than standard windows but are a popular choice for kitchen extensions.
- Finish specification – the cost figures below cover the build itself (structure, roof, external finish, first-fix). Kitchens, flooring, sanitaryware and decorating are usually specified separately, so factor these into your overall budget.
- Structural work to the existing house – removing load-bearing walls to open the extension into the existing kitchen or living space adds steelwork and building control costs.
- Access – how easily materials and machinery can reach the build site affects labour time and cost.
Cost per square metre breakdown
Across Solihull, a single storey extension typically costs £1,800–£2,500 per m². This is a build-only figure and doesn’t include kitchen fit-out, high-end glazing upgrades, or landscaping.
A typical 20–30m² single storey kitchen extension costs in the region of £30,000–£70,000, depending on specification and complexity.
Here’s how that looks by size:
| Size | Cost at £1,800/m² | Cost at £2,500/m² |
|---|---|---|
| 15m² | £27,000 | £37,500 |
| 25m² | £45,000 | £62,500 |
| 35m² | £63,000 | £87,500 |
These figures are a general guide for budgeting purposes. Every property and every design brief is different, so the only way to get an accurate cost for your project is a site visit and a detailed quote.
Do you need planning permission
Many single storey rear extensions in Solihull fall under permitted development, meaning you may not need full planning permission. Under permitted development rules, a single storey rear extension can typically extend:
- Up to 4m from the original rear wall for a detached house
- Up to 3m from the original rear wall for semi-detached and terraced houses
- Up to 6m (semi-detached/terraced) or 8m (detached) under the Larger Home Extension scheme, which requires a neighbour consultation scheme administered by the council rather than a full planning application
Permitted development rights can be restricted or removed entirely, for example if your property is in a conservation area, is listed, or has had previous extensions that already used up the allowance. Side-return and wraparound extensions have their own separate rules and limits.
Because these rules change and every property’s planning history is different, always verify your specific entitlement with Solihull Metropolitan Borough Council before finalising your design, or ask us to advise as part of your initial consultation. For general guidance on when planning permission applies, see our planning permission guide for extensions and loft conversions.
How long does it take
Most single storey extensions in Solihull take 10–14 weeks on site, from breaking ground to completion. Before that, allow around 6–8 weeks for the design and planning stage, covering drawings, planning or permitted development sign-off, and building regulations approval.
So from initial design through to move-in, a realistic total timeline is around 16–22 weeks. Larger or more complex projects, such as wraparound extensions or those requiring structural alterations to the existing house, can take longer.
Ways to keep costs down
- Keep the footprint efficient. A well-planned smaller extension that makes better use of the existing house often delivers more usable space than a larger one bolted on without reworking the layout.
- Choose a simpler roof where you can. A flat or single-pitch roof costs less than a complex hipped or vaulted design.
- Stick to permitted development where possible. Designing within permitted development limits avoids the cost and time of a full planning application.
- Plan your glazing and finishes early. Bi-fold doors, roof lanterns and higher-spec kitchens are often where budgets creep, so decide on these early rather than upgrading mid-build.
- Get a detailed, itemised quote. A clear breakdown of what’s included, structure, roof, glazing, first-fix, versus what’s excluded, kitchen, flooring, decorating, helps you avoid unexpected costs later.
- Use a registered, insured builder. Problems caused by uninsured or unqualified work can be far more expensive to put right than the savings made on the original quote.
Get a free quote
If you’re planning a single storey extension in Solihull or the surrounding West Midlands, HK Builders Ltd can provide a free, no-obligation quote based on your specific property and design. We’re FMB-registered, fully insured, and have over 20 years’ experience delivering rear, side-return and wraparound extensions across Solihull, Dorridge, Knowle, Shirley, Olton, Earlswood, Sutton Coldfield, Harborne, Moseley, Coventry and Redditch. If you’re weighing up your options, see our full house extensions overview or read single storey vs double storey extension: which is right for your home?
Call us on 07393 194 336 or email info.hkbuilders@gmail.com to arrange a site visit and discuss your project.
Call 07393 194 336Get a free quote