How Much Does a House Extension Cost in Knowle?

What Extensions Actually Cost in Knowle

Knowle commands premium prices, and the quality of work reflects that. Here's what we're seeing:

Single storey extensions run at £2,400-£3,000 per square metre. A 20m² extension costs £48,000-£60,000. Scale up to 35m² and you're looking at £84,000-£105,000.

Double storey extensions give you more space for your money - around £2,200-£2,800 per square metre. A 40m² double storey (20m² per floor) typically comes in at £88,000-£112,000.

Side returns work brilliantly on Knowle's period properties, filling that awkward gap down the side. Budget £60,000-£80,000 for a quality side return extension.

What Affects Your Final Bill?

Property Age and Style

Knowle has gorgeous Victorian and Edwardian homes, plus characterful Arts and Crafts properties. These often need sympathetic approaches - matching brickwork, appropriate rooflines, sometimes dealing with solid walls or unusual foundations. It adds to costs but protects your property's character and value.

What Room You're Creating

A simple dining room costs less than a fully-fitted kitchen with island, appliances, and underfloor heating. Adding a bathroom means plumbing costs. Bi-fold doors cost more than standard windows. Your choices stack up quickly.

Site Access

Can lorries and skips get down your driveway? Is there side access for materials? Restricted access means everything takes longer and costs more. It's a genuine factor in pricing.

Ground Conditions

Some Knowle properties sit on clay soils. Others have quirky foundations. We don't know until we dig, but awkward ground conditions can add £3,000-£8,000 to foundation costs.

Building a Kitchen Extension

Most Knowle extensions are kitchen extensions. People want that open-plan living space with proper entertaining areas. Here's realistic budgeting:

For a 30m² single storey kitchen extension:

• Main construction: £72,000-£90,000
• Quality kitchen (mid to high spec): £15,000-£35,000
• Flooring (engineered wood or tiles): £3,000-£6,000
• Bi-fold or sliding doors: £4,000-£10,000
• Lighting and electrics: £2,000-£4,000

Total: £96,000-£145,000 depending on specifications.

That's proper quality work with decent materials. You can spend less with budget finishes, or more with luxury specifications.

Will It Increase Your Property Value?

Knowle's property market is strong. Quality extensions typically add 10-20% to property values, often exceeding what you've spent.

Example: £500,000 house with £80,000 extension. Adding 15% value means £75,000 increase. You're essentially breaking even whilst getting years of improved living space.

But be careful not to over-develop. If neighbouring properties are worth £500,000-£550,000, spending £150,000 on an extension might not give you full return. We'll give you honest advice on this.

Planning Permission in Knowle

Not every extension needs planning permission. Permitted development covers:

Single storey rear extensions:

• Up to 6m for terraced/semi-detached
• Up to 8m for detached
• Not higher than existing building

Two storey extensions:

• No closer than 7m to rear boundary
• Under 3m from boundary
• Within height limits

But watch out for:

• Conservation areas (parts of Knowle have restrictions)
• Article 4 directions removing permitted development
• Properties with previous planning conditions

Planning applications cost £206 and take 8-12 weeks. Solihull Council handles Knowle applications, and we know what they approve and what they reject.

Building Regulations

Every extension needs building regs approval. Non-negotiable. This covers structural safety, insulation, drainage, fire safety. Building control inspects at key stages and issues a completion certificate.

Budget £800-£1,500 for building control fees. You need that completion certificate when you sell, so cutting corners isn't an option.

Timeline Expectations

Typical project runs:

With planning permission:

• Planning application: 8-12 weeks
• Pre-construction prep: 2-3 weeks
• Groundworks and foundations: 2-3 weeks
• Main build: 8-12 weeks
• First fix (electrics, plumbing): 2 weeks
• Second fix and finishing: 3-4 weeks

Total: 25-35 weeks from planning submission to completion.

Under permitted development: Knock off the planning time - you're looking at 15-20 weeks.

Weather affects timelines. So do material deliveries. We give realistic schedules, not optimistic ones.

The Disruption Factor

Extensions are disruptive. Be prepared for:

• Builders on site 8am-5pm weekdays
• Dust, noise, general building site atmosphere
• Potentially no kitchen for weeks
• Making constant decisions on details
• Skip outside your house
• Neighbours asking questions

Most people stay in their homes throughout. Some decamp to family or rent somewhere for the worst weeks. We minimise disruption where possible, but it's still a building site.

Why Choose Use Your Space?

We've built extensions throughout Knowle for years. We understand the local property types, we know what quality Knowle homeowners expect, and we deliver professional work that genuinely adds value.

We're not the cheapest quote you'll get. We're the best value. Quality materials, experienced trades, proper project management, full compliance, and customer service that doesn't vanish after completion.