Should I get design advice before fixing my refurbishment scope?

Yes — before you fix the budget, not after. On the South London flat project in Your Seven Step Home Extension Plan, the owner had already scoped a £15,000 refurbishment and had it valued at £325,000. A redesigned layout costing around £5,000 more was valued at £350,000 — £25,000 more value for £5,000 more spend, a £20,000 net gain. The cheapest scheme is not automatically the best-value scheme.

Does an open-plan layout add value to a flat?

On this South London flat it did. Turning the front lounge into a second double bedroom and opening the whole back addition into an open-plan kitchen, dining and lounge area leading to the garden lifted the agent's valuation from £325,000 to £350,000 — and the flat ultimately sold for £385,000. Every property is different, so test alternative layouts against agent valuations before you commit.

How do I compare two refurbishment options properly?

Have both options drawn up, then ask a local estate agent to value each finished scheme. That is exactly what happened on the South London flat project in this case study: drawings were prepared showing both layouts, the agent priced both, and the numbers made the decision. Comparing build cost alone tells you half the story — you need the end value too.

What professional fees should I expect on a building project?

Typical professional fees run at around 10–12% of build cost for full architectural and project management support. On small projects you can buy only the elements you need — for example technical drawings, structural calculations and party wall support — and project manage the rest yourself, as the owner did on the South London flat project in this case study.

Case Study: The £5,000 Redesign That Added £25,000 of Value

Most of the case studies we share are about things going wrong on site. This one is different — it's about a project that nearly went wrong before anyone picked up a tool, because the plan itself was the wrong plan. It comes from Ashton's book, Your Seven Step Home Extension Plan, where it appears as the first of five case studies, and it's the clearest example we know of a simple principle: design for value, not just for cost.

The starting point

Emma owned a one-and-a-half bedroom ground-floor flat in South London and had decided to enlarge the small second bedroom to enhance the flat's value. The property was a typical two-storey building: lounge to the front, bedroom to the rear, kitchen in the back addition, and a poorly positioned bathroom and lobby at the rear providing side access to the garden.

Her plan was sensible enough on paper:

Relocate the bathroom to the rear of the main building
Enlarge the smaller bedroom into a good single bedroom
Create a kitchen/dining room in the back addition, keeping the existing side door

The local estate agent valued the refurbished flat at £325,000, and Emma estimated the works at £15,000. We were engaged for the technical parts — building control drawings, structural calculations and the party wall matters.

And that could easily have been that. Scope fixed, budget fixed, valuation obtained. Most projects at this point are already on rails.

The near-miss: a sound plan that left money on the table

Here's the thing about Emma's plan: nothing was wrong with it. It would have worked. The flat would have been improved, the valuation supported it, and the budget was affordable.

But "nothing wrong with it" is not the same as "the best use of the property". Looking at the same floor plan, there was a better idea:

Change the front lounge into a bedroom — giving the flat two double bedrooms instead of one-and-a-bit
Move the bathroom
Open the entire back addition into one open-plan kitchen, dining and lounge area leading straight into the garden

Estimated cost: £20,000 — with an honest warning attached. Because Emma was a newbie developer, Ashton told her to expect to overspend by around £2,000, allowing her room to make a few mistakes and learn a trick or two. That kind of built-in contingency honesty matters; we've written before about why budgets need slack for reality, not just line items.

Emma was perplexed — not because she disliked the design, but because she didn't have the additional £5,000.

Let the numbers make the decision

Rather than argue about it, the drawings were prepared showing both options, and Emma took them to the estate agent for comparable valuations.

The open-plan scheme with two double bedrooms came back valued at £350,000 — an additional return of £20,000 for the extra spend.

That's the discipline worth copying. Not "trust the designer's taste", not "go with your gut" — draw both schemes, price both schemes, value both schemes, and let the margin decide. When you can see £5,000 of extra cost buying £25,000 of extra value, the decision makes itself.

Closing the £5,000 gap

A better design is worthless if you can't fund it. Two practical moves closed the gap:

The bathroom and kitchen fittings went on zero percent credit card deals — leveraging the extra £5,000 without expensive borrowing.
A trusted builder was introduced who was prepared to wait for his final payment until the property sold.

Ashton kept an eye on the project throughout — enough oversight to make sure Emma didn't get into hot water, while still leaving her room to make her own mistakes. And she made a few, like over-designing the bathroom. That's fine. Small, survivable mistakes on a controlled project are how first-time developers learn.

The result

The flat was under offer in six days at £350,000. Then, due to problems with the freeholder, the sale fell through — a reminder that even well-run projects hit turbulence that has nothing to do with the building work. The good news: it sold three months later for £385,000.

So the final scorecard against the original plan: roughly £5,000 of extra build cost, a valuation £25,000 higher, and an eventual sale price £60,000 above the original scheme's valuation.

What Emma did right

The book's verdict on this project is a checklist of good habits, and every one of them transfers to a home extension or renovation:

She sought professional advice. Emma knew to ask — and the initial idea-stage advice was given free of charge. The expensive mistake is not asking at all, or asking only after the scope is fixed.
She purchased the elements of advice she could afford. She didn't buy full project management; she bought technical drawings, structural calculations and party wall support, and was happy to project manage a small £15,000-scale project herself. Professional support isn't all-or-nothing — buy the pieces that carry the most risk.
She worked out her own costs. She came to the table with her own estimate, which made the comparison between options honest.
She worked with friends and family to reduce costs.
She leveraged materials costs with sensible 0% credit card offers — cheap, short-term funding matched to a short-term project.
She had a written agreement with the builder, with a professional overview. Even on a small job between friends, the agreement went in writing and someone independent kept watch. Compare that with what happens when neither is in place — our Hook Road house-to-flats project shows the same contract-and-oversight discipline at ten times the budget.

What you should do differently

If you're planning a refurbishment or extension, the lesson isn't "spend more". It's this:

Don't fix your scope before you've tested it against an alternative. Emma's original plan was costed, valued and ready to go — and it was still the wrong plan, to the tune of £20,000. The moment to bring in design thinking is before the budget hardens, when a different layout can still be drawn, priced and valued alongside your own idea. That's also the stage where the fee for that thinking is smallest.

The second lesson: judge schemes on margin, not cost. The £15,000 scheme was "cheaper" and worth less; the £20,000 scheme cost more and returned more. If you only ever compare build costs, you will systematically pick the wrong projects.

This is exactly how we approach home renovations and refurbishments today: feasibility and layout options first, valuations against each option where value is the goal, and only then a fixed scope and budget. For flats and houses where the layout itself is the opportunity, our architectural and planning service covers that options stage as one process.

The full story — including the numbers and the checklist it produced — is in Your Seven Step Home Extension Plan, where Ashton walks through all seven steps of running a project like this without the stress.

Thinking about a refurbishment?

If you have a flat or house you suspect could be worth more with a better layout, don't fix your scope yet. Book a free consultation and we'll tell you honestly whether a redesign would pay for itself — and by how much.