Planning a House Extension in Birmingham: Costs, Permissions & Expert Tips
Planning a House Extension in Birmingham: Costs, Permissions & Expert Tips
If you love your Birmingham home but feel you’ve outgrown it, a house extension can be the perfect solution. From stylish kitchen-diners in Edgbaston to double-storey extensions in Sutton Coldfield, homeowners across the West Midlands are transforming their properties instead of moving. An extension not only adds space but can also increase property value and make day-to-day life more comfortable.
At Greens Construction, we’ve spent years helping Birmingham families expand and upgrade their homes with stress-free, well-managed building projects. This comprehensive guide will walk you through everything you need to know before starting your extension — including costs, planning permission, design ideas, and how to choose a trustworthy builder.
Why Choose a House Extension in Birmingham?
Many of our clients come to us facing the same decision: move or improve? The Birmingham property market can be competitive and expensive, especially in desirable areas like Moseley, Harborne, and Solihull. Extending your existing home is often a smarter, less disruptive alternative. Here’s why:
- Stay in the area you love — Keep your current commute, local schools, and community ties.
- Avoid moving costs — Stamp duty, legal fees, and removal expenses can add up quickly.
- Add significant value — A well-designed extension can add 10–20% to your home’s resale price.
- Create a bespoke layout — Whether you need a bigger kitchen, an extra bedroom, or a home office, an extension lets you tailor your property to your lifestyle.
- Improve energy efficiency — Modern construction methods often make extensions warmer and cheaper to run than older parts of the house.
Local insight: Extensions are especially popular in Birmingham suburbs where plot sizes allow room to build outwards — such as Kings Heath, Northfield, and Bournville — but we also help with creative loft and garage conversions in more compact city settings.
Understanding the Costs of a House Extension in Birmingham
One of the first questions every homeowner asks is “How much will it cost?” The truth is, there’s no one-size-fits-all answer. Prices vary depending on the type of extension, materials, and site conditions. Here’s a realistic Birmingham-based cost guide to help you budget:
Type of Extension Typical Cost per m² (Birmingham area)
Single-storey rear or side extension £1,500 – £2,200
Double-storey extension £1,800 – £2,800
Loft conversion with dormer £1,600 – £2,400
Garage conversion £800 – £1,200
Key factors affecting cost:
- Size & complexity — More square metres and unusual shapes increase costs.
- Foundations & ground conditions — Clay-heavy Birmingham soil can sometimes require deeper footings.
- Roof style — Flat roofs tend to cost less; pitched or vaulted ceilings add expense but also impact.
- Windows & doors — Large bi-fold or sliding doors to the garden are popular but can be pricier.
- Plumbing & electrics — Relocating services or adding bathrooms increases spend.
- Finishes & fittings — Luxury kitchens, underfloor heating, and bespoke joinery push budgets higher.
Pro tip: Always include a 10–15% contingency for unexpected issues, especially with older homes where hidden pipework or structural challenges can arise.
Greens Construction provides detailed, transparent quotations. We break down every stage of the build so you know exactly where your money is going — no hidden surprises.
Planning Permission & Building Regulations in Birmingham
Understanding the rules before you build is crucial. Many homeowners are surprised by how permitted development rights work.
Permitted Development
In Birmingham, you may not need full planning permission if your extension meets certain criteria:
- Single-storey rear extensions up to 3m (terraced) or 4m (detached) usually don’t need permission.
- Double-storey extensions can be built if they don’t extend beyond the rear wall by more than 3m and stay within height restrictions.
- Materials must be similar to the existing house.
- You can’t cover more than 50% of the land around the original house.
Important: These rules change if your property is listed, in a conservation area, or has previous extensions. Areas such as Bournville Village Trust often have stricter design guidelines.
Planning Permission
You will need planning permission if:
- Your extension exceeds the size/height limits.
- You’re adding a two-storey side extension.
- You live in a flat, maisonette, or listed building.
- Your design significantly affects neighbours’ light or privacy.
Building Regulations
Regardless of planning permission, Building Regulations approval is always required. This ensures:
- Structural stability
- Fire safety
- Proper insulation
- Safe electrics and plumbing
At Greens Construction, we regularly handle planning applications and Building Regulations approvals on behalf of our clients, making the process smooth and hassle-free.
Choosing the Right Builder in Birmingham
Selecting the right builder can make or break your project. Here’s what to look for:
- Local reputation — Birmingham-based builders understand planning rules and have trusted supplier networks.
- Portfolio of similar work — Ask to see completed extensions like yours.
- Customer reviews — Check Google, Trustpilot, or request client references.
- Transparent quotes & contracts — Beware of vague pricing or verbal promises.
- Communication skills — Your builder should keep you updated and involved.
Why choose Greens Construction: We’re a family-run Birmingham construction company with a reputation for quality, reliability, and personal service. Our clients appreciate our open communication, experienced team, and attention to detail.
How We Work — From Idea to Completion
We know building work can feel overwhelming. That’s why we use a proven 5-step process:
- Free consultation & site visit
We visit your property, discuss ideas, and advise on feasibility. - Detailed quotation & schedule
Transparent pricing with clear timelines — no hidden extras. - Design & planning support
Assistance with architectural drawings, planning permission, and Building Regulations. - Construction & project management
Skilled tradesmen, efficient scheduling, and regular progress updates. - Finishing touches & handover
We leave your space clean, complete, and ready to enjoy.
Our goal is to minimise disruption and keep your project running smoothly, from the first sketch to the last coat of paint.
Case Study: Modern Kitchen Extension in Moseley
One recent client wanted a bright, open-plan kitchen-diner overlooking their garden. We handled:
- Permitted development checks
- Structural steel installation for open-plan living
- Large aluminium bi-fold doors for natural light
- Underfloor heating and sleek contemporary finishes
The result: a stunning family space that added both square footage and significant market value.
Ready to Start Your Birmingham House Extension?
A house extension is a big investment — but with the right planning and builder, it’s one of the most rewarding projects you can undertake.
If you’re ready to discuss your ideas or simply want advice about costs, planning permission, or design options, we’re here to help.
Email:
info@greensconstruction.co.uk
Call Dave: 07779 570487 or Josh: 07773 082203
Or
request your free no-obligation quote here »
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