How Much Does a Two-Storey Extension Cost? (And Is It Worth It?)

How Much Does a Two-Storey Extension Cost? (And Is It Worth It?)

If your family’s outgrown your home—or you’ve just moved somewhere with potential—you’ve probably asked yourself:
“Should we extend, or just move?”

With construction costs rising and the property market shifting, this is more important than ever to get right. Whether you’re relocating from South London to Stockport, or simply trying to create the forever home you’ve always wanted, here’s a breakdown of what a two-storey extension might really cost—and how to make the most of your budget.

What’s the Ballpark Cost?

The cost of a two-storey side or rear extension in the North West currently sits somewhere between:

£120,000 and £250,000+

That’s assuming you’re adding:

• A fourth bedroom upstairs

• A bigger kitchen-diner downstairs

• Possibly a utility room, downstairs loo, or garage rebuild

This includes construction, internal finishes, and a realistic level of architectural and professional fees. You’ll often see costs quoted “per m²” – for two-storey extensions, expect:

£2,400 – £3,000+ per m², depending on the finish, complexity, and how much you’re opening up walls

What About Architects’ and Consultants’ Fees?

Beyond bricks and mortar, there’s the paperwork, permissions, and safety to deal with. That means bringing in architects, structural engineers, and compliance consultants. Here’s what to budget:

These are essential stages in taking your dream off Pinterest and making it real. They also help protect you from nasty surprises later—like failed planning applications, over-engineered designs, or builders unable to quote accurately.

Can You Do It Cheaper?

Yes—and no. Here are some cost-saving principles:

• Simplify the design: A straight-up two-storey box is far more cost-effective than one with lots of setbacks, angles, or glass.

• Avoid major steelwork: The bigger your knock-through, the more expensive your structural elements will be.

• Keep plumbing where it is: Moving bathrooms and kitchens adds cost.

• Consider internal reconfigurations first: Sometimes, simply reshuffling internal walls (e.g. swapping the bathroom and small bedroom) gives you what you need for far less money.

For example, one client moved their bathroom to the centre of the house and gained two decent-sized bedrooms without even extending. Another added a downstairs loo and utility in the garage space instead of building out.

Is It Worth Doing?

It depends on your priorities:

• Need more space? Yes.

• Want to create a custom kitchen/living/dining space? Definitely.

• Want to increase the property’s value long-term? Usually—but get an estate agent’s opinion.

• Expecting to live through the works? Think twice. Most people move out (at least temporarily).

Sometimes, buying a house with the space already added can be a smarter move financially—especially if construction costs are high in your area. But buying a doer-upper gives you the chance to make it your own, exactly how you want it.

Start With a Design Workshop

Before you dive in, get clarity. A concept design workshop helps you:

• Explore multiple layout options

• Understand what’s possible under planning

• Get a sense of what each option might cost

• Work out what you actually need vs. what you think you want

At Pride Road, we offer:

• Online or in-person workshops

• Hand-drawn concept options

• Advice on budget, planning and next steps

Workshops start at £450 for a half-day or £600 for a full day, depending on the complexity of your project.

Bottom Line

• A two-storey extension can cost as little as £120,000, but expect the full project (including fees and finishes) to push closer to £150,000–£250,000.

• If you’re on a tighter budget, focus on reconfiguring existing space or start with a single-storey option.

• Get professional guidance early—it’ll save you stress and cost down the line.

Want help exploring what’s possible with your new home?
Book a Concept Workshop

Let’s turn your big ideas into something buildable.