London's Renovation Reckoning:
What 107 Interior Designers
Say You're About to Get Very Wrong

The Timing Couldn't Be More Consequential

Right now, as you read this, the Valuation Office Agency is conducting property assessments across London. These are not routine valuations. They are the baseline measurements that will determine which homes cross the £2 million threshold for the government's new High Value Council Tax Surcharge — the so-called mansion tax — which takes effect in April 2028 but is assessed on 2026 property values.

The implications for anyone renovating in 2026 are significant and chronically underappreciated. A well-executed kitchen extension in Wandsworth, a finished basement conversion in Notting Hill, a refurbished Victorian terrace in Islington — these are precisely the properties the VOA is scrutinising. The renovation decisions being made right now will be locked into valuations that determine tax liability for the next five years.

It is in this context that FCI London — with four decades of experience at the apex of London's interiors market — conducted a survey of 107 practising London interior designers between January and February 2026. What they told us is both granular and urgent. The professionals closest to London's renovation economy are watching homeowners make the same expensive mistakes, at scale, in a year when the stakes have never been higher.

Budget Landscape: A Market Splitting in Two

The first question the data answers is deceptively simple: are London renovation budgets going up or down? The answer, as it turns out, is both — and the split is the most revealing finding in the entire survey.

When FCI London asked designers how client budgets had shifted compared to the prior year, no single direction dominated. A significant proportion reported budgets holding stable. Comparable cohorts saw them rise sharply or fall sharply. The market is not moving in one direction. It is fracturing along wealth lines, with a chasm opening between ultra-prime clients — largely unaffected, in some cases spending more than ever — and the mid-market tier, where the squeeze is becoming acute.

The drivers of hesitation were consistent: Labour's housing and planning policy announcements, the spectre of wealth taxes, and the cumulative psychological toll of years of economic uncertainty. One designer summarised it plainly: "Less money in pockets, wealth taxes, VAT on school fees, and anxiety in the housing market — it's created a paralysis in the middle."

The paradox: the clients who are spending are spending significantly more. Multiple designers working exclusively in the ultra-high-net-worth bracket reported budgets as "uncapped." At FCI London, where we work with discerning clients from Mayfair to Knightsbridge, we see this dynamic first-hand: the appetite for exceptional interiors at the very top of the market is not merely intact — it is intensifying. What is suffering is the aspirational middle, where a combination of material cost inflation, political uncertainty and looming tax changes is creating a genuine chill.

The Hidden Costs That Are Destroying Projects

Ask any of the 107 designers in this survey what clients are genuinely unprepared for, and a remarkably consistent picture emerges. It is not materials. It is not even labour — though labour costs have increased sharply, with some respondents citing increases of 30% and above. The single biggest hidden cost, cited repeatedly, is what you find when you open up the walls.

Structural discoveries made during demolition — outdated wiring, corroded plumbing, hidden rot, rotten joists, non-compliant foundations — can instantly trigger mandatory upgrades that force homeowners to modernise an entire system rather than a single room. "The crumbling plaster, the dodgy electrics, the damp that has been painted over. There must always be contingency," as one designer summarised.

Contractor preliminaries were flagged repeatedly as costs that "quietly swallow a huge chunk of the budget" before a single decorative decision is made. Site setup, scaffolding, welfare provision, skip permits, programme management — these are the invisible engine costs of any serious London renovation. Time-related slippage compounds everything: every week a project overruns, prelims stack up, storage costs mount, temporary accommodation bills accumulate.

The professional consensus: build a minimum 15–20% contingency into any London renovation budget, treat it as fixed not aspirational, and brief your client to expect to use it in full.

Open-Plan Is Over. No, Really This Time.

One of the clearest signals in FCI London's survey data is the accelerating death of the open-plan layout. When asked whether they were seeing a decline in open-plan living requests, over half of designers said yes — and the dominant replacement is what respondents call "broken plan": spaces zoned by internal windows, screens, changes of level and joinery rather than knocked through entirely.

This is not merely a design trend. It reflects a fundamental shift in how Londoners actually use their homes. Remote and hybrid working has transformed kitchens and living rooms into multi-functional spaces that must manage competing acoustic and privacy demands simultaneously. The Instagram-era dream of the vast open-plan kitchen-diner is giving way to something harder to photograph but far more liveable.

The Kitchen Is Still King — But the Bedroom Suite Is Rising

When FCI London asked which room commanded the highest percentage of renovation budgets, the kitchen and dining space dominated by a wide margin. This is consistent with what our design team at FCI London has observed across client briefs for several years: the kitchen is no longer purely functional. It is the social engine of the home — the space that signals taste, investment and intent.

But a significant secondary pattern is emerging: the primary bedroom suite is gaining ground. Designers attribute this to a broader wellness shift. Clients are investing in spa-calibre bathrooms, integrated dressing rooms, and sleeping environments engineered for circadian rhythm and acoustic calm. Several respondents cited the prevalence of "The Soho House Bathroom" as a reference point — warm, textural, tactile, deliberately un-clinical. At FCI London, we have seen this directly in briefs: clients who once prioritised the kitchen budget are now asking us to apply equal rigour to the bedroom floor.

Colour in 2026: Brown Is the New Grey (Even If Grey Won't Die)

On colour, the FCI London survey produces one of its most striking paradoxes. Millennial Grey is simultaneously the most hated and most-specified shade in London right now. When designers were asked which colour they would ban, it dominated by a wide margin. When asked which colours are actually appearing in live briefs, it dominated there too.

The "new neutral" story is consistent and coherent: the design community is moving decisively toward warmth, depth and patina. Chocolate and espresso browns led the vote by a significant margin. Terracotta and rust followed. What unites these choices is a shift away from cool, recessive tones toward colours with thermal weight — shades that make rooms feel inhabited rather than staged.

The buzzword of 2026? According to FCI London's survey, it is Radical Authenticity — outpacing Dopamine Decor, Loud Budgeting and Digital Surrealism by a wide margin. After years of Instagram-optimised, showroom-perfect interiors, clients want spaces that feel genuinely personal, intentionally imperfect, and unmistakably theirs.

Design Era Revival: The 1970s Leads the Comeback

When asked which design era is experiencing the most significant revival, the 1970s topped the survey. Respondents described an "Intellectual 70s" sensibility — low-slung furniture, rich browns and rusts, olive and amber, tactile materials, moody layering — filtered through a restrained, design-literate lens. This is not shag pile for its own sake. It is the warmth and materiality of that decade reinterpreted through contemporary craft and proportion.

The 1990s Minimalism / Japandi evolution followed closely, reflecting the enduring appetite for pared-back interiors with natural material honesty. English Country House Maximalism continued its rehabilitation at the upper end of the market — precisely the tier where FCI London has seen the strongest client appetite for the new "lived-in heritage" aesthetic.

The Trends Designers Are Banishing in 2026

Grey velvet dominated, followed by fake panelling and slat walls, TVs above fireplaces, and over-styled shelfies. These are the residue of the mid-2020s maximalist Instagram era now curdling into self-parody. Slat wall panelling was singled out for extinction by multiple respondents — one simply wrote: "Death to slat wall panelling."

The pattern is directly relevant to anyone renovating with resale in mind. Features that sold properties in 2022–23 are actively working against you with the design community in 2026. The features that add genuine enduring value — quality lighting, material honesty, well-proportioned joinery, considered space planning — are what FCI London's design team has always championed, precisely because they age well across market cycles.

The Basement Warning London Homeowners Keep Ignoring

Basement conversions came up throughout the FCI London survey as a persistent site of client miscalculation, magical thinking and expensive regret. The mistakes are remarkably consistent across respondents regardless of the market segment they work in.

The near-universal expert view: treating a basement conversion as a standard extension rather than a fundamentally different engineering project. Waterproofing is chronically underestimated. Ceiling height is not maximised during the dig — the one moment when adding height costs relatively little. Ventilation is ignored until it becomes a damp problem.

• 1
  Underestimating waterproofing, tanking and ground conditions
  82%
• 2
  Failing to maximise ceiling height during the dig
  64%
• 3
  Ignoring ventilation and air quality until problems emerge
  58%
• 4
  Not treating it as a high-risk engineering project requiring specialists
  51%
• 5
  Designing finishes before structural and waterproofing strategy is locked
  44%
• 6
  Prioritising maximum floor area over natural light and usable volume
  39%

In the context of 2026 mansion tax valuations, this matters doubly. A poorly executed basement conversion will not only fail to add expected value — it may create damp, structural and compliance problems that actively complicate future sales and valuations, at precisely the moment those valuations carry five years of tax consequence.

AI in the Studio: Tool, Not Threat

The FCI London survey asked designers directly whether AI poses a threat to the profession within five years. The majority said no — but the nuance behind that answer matters. The dominant position was not denial but clear-eyed pragmatism: AI is a tool, and the designers using it well are gaining an efficiency advantage over those who refuse to engage.

The threat model that did resonate was narrower: several designers acknowledged that AI could plausibly replace technical drafters and junior designers performing computational or repetitive tasks. The distinctly human value — accumulated taste, empathy, accountability, the management of complex multi-stakeholder projects under real constraints — was seen as durable.

That assessment aligns precisely with what FCI London has observed in 40+ years of working with design professionals: the irreplaceable value is always in the decisions, not the drawings.

Supply Chain Reality: Bespoke Lead Times Are Stretching

The survey confirms what our procurement teams at FCI London see daily: the dominant lead time quoted by designers for bespoke European furniture is 10 to 14 weeks, with a significant proportion now quoting 14 to 16 weeks, and a notable cohort citing six months or more for complex bespoke commissions.

Post-Brexit trade friction — import delays, tariff friction, administrative burden, and the loss of European trade talent from London's ecosystem — was cited by nearly a third of respondents as an ongoing operational reality. FCI London's direct relationships with over 700 European brands, many developed over 25+ years, give us a procurement advantage that directly benefits clients: orders placed through us are tracked across our own logistics infrastructure from factory to installation.

The practical implication for clients: if you are commissioning bespoke furniture for a project completing in late 2026, those orders need to be placed now. The cost of getting this wrong — in delays and project extension costs — dwarfs the cost of early planning.

What the Professionals Predict: London Interiors 2026 and Beyond

The final question in the FCI London survey asked designers for their bold prediction for the industry in 2026 — the thing no one is talking about. The responses were, in aggregate, more coherent than individual predictions usually are. Several clear themes emerged.

The death of trend-led design was the most consistent prediction. Across the survey, designers articulated a growing client appetite for spaces that are personal, enduring and emotionally resonant rather than aligned with any particular moment's aesthetic. "Design for how spaces make you feel, not how they photograph" was a sentiment expressed in various forms by multiple respondents.

Wellbeing as a structural brief element — not as a bolt-on feature, but the active consideration of acoustics, air quality, natural light, circadian rhythm, and even scent as primary design determinants — was cited by several designers as the next significant shift. At FCI London, where our design consultations increasingly incorporate these dimensions, we believe this is not a trend but a permanent evolution in what clients expect from exceptional interiors.

The professionalisation of the industry was a recurring concern. Multiple respondents predicted that the current squeeze will accelerate a consolidation, with underqualified practitioners exiting the market and surviving studios becoming more selective, more explicit about their value, and more focused on full-project delivery rather than decorative input alone.

For FCI London — a business that has spent four decades earning the trust of London's most discerning clients and design professionals, from our 30,000 sq ft showroom in NW London to projects across Mayfair, Chelsea, Kensington, Notting Hill and beyond — these predictions are familiar. They describe what we have always believed: that extraordinary interiors are not the product of trends, but of authority, patience, and an uncompromising commitment to the quality of every single decision made along the way.

The renovation decisions being made in London in 2026 will matter more than usual. They will be assessed by the Valuation Office Agency for mansion tax purposes, judged by a design community moving sharply away from Instagram aesthetics, and lived in by families navigating a city that has rarely felt more uncertain — or more full of possibility.