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Planning8 min read • Updated Jan 2025

Extension vs New Kitchen: Which Adds More Value?

£50k luxury kitchen vs £75k extension: which is the smarter investment? Kitchen renovations add 5-10%, extensions add 10-15%. Complete ROI analysis, decision framework, and combined strategies.

Quick Answer

For most London homeowners, a combined approach delivers the best ROI: modest extension (£35-48k) + mid-range kitchen (£20-24k) typically returns 130-150%. Kitchen-only (120-160% ROI) wins on smaller budgets; extension-only (90-115% ROI) wins when space is fundamentally inadequate.

120-160%

Kitchen ROI

90-115%

Extension ROI

130-150%

Combined ROI

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The ROI Reality: Extensions Win on Paper

According to Zoopla's property value analysis, a full kitchen redesign (£45k) adds approximately 15% to property value, while Which? reports extensions can add 10-15% value. However, the raw ROI numbers don't tell the full story.

ScenarioInvestmentValue IncreaseROI %Net Gain
£700k home + £45k kitchen£45,000£70,000 (10%)156%+£25,000
£700k home + £80k extension£80,000£91,000 (13%)114%+£11,000
£700k home + £45k kitchen + £35k small extension£80,000£119,000 (17%)149%+£39,000

* Assumes £700k London property. Value increases are averages - actual results vary by property, location, and execution quality.

Key insight: Kitchen renovations deliver better ROI percentages (120-160%) than extensions (90-115%) because they cost less. However, extensions add more absolute value. The combined approach often delivers the best outcome: modest kitchen refresh + small extension maximizes both ROI and total value added.

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When New Kitchen Is the Smarter Choice

1. You Have Adequate Space Already

If your kitchen is 15m²+ (160+ sqft), you don't need more space - you need better design and finishes. Extension won't solve the problem if your existing kitchen is poorly laid out or outdated.

Example: 3-bed terrace with 18m² kitchen. Spending £45k on premium units, integrated appliances, and layout optimization delivers better results than spending £80k adding 8m² of mediocre space.

2. You're Selling Within 2-3 Years

Kitchen renovations take 4-8 weeks vs 4-6 months for extensions. You'll enjoy the benefit sooner, and the faster timeline means less disruption before sale. Kitchen ROI is also immediately visible to buyers, while extension value takes time to appreciate.

  • Kitchen: 120-160% ROI on £40k-50k investment = £8k-30k net gain
  • Extension: 90-115% ROI on £75k-85k investment = £0-13k net gain (or loss)

3. Budget Under £50k

£45k-50k buys a superb kitchen but only a very basic small extension. Extensions under £60k tend to feel cheap (budget materials, minimal design) and won't command premium prices. Better to invest in exceptional kitchen than mediocre extension.

£45k Kitchen Gets You:

High-end German units, Quartz worktops, Bosch/Miele appliances, designer taps/lighting, professional installation

£45k Extension Gets You:

Basic 10m² extension, budget materials, IKEA kitchen, standard finishes, builder-grade everything

4. Planning/Party Wall Complications

If your extension requires planning permission (conservation area, Article 4 direction, difficult neighbors), the 6-12 month timeline and £5k+ additional costs might not be worth it. Kitchen renovation has zero planning bureaucracy.

  • No party wall notices/costs (£1k-3k saved)
  • No planning application (£258+ saved, 8-13 weeks saved)
  • No structural engineer for foundations (£1.5k-2.5k saved)

5. You Don't Need Extra Bedrooms

Extensions that add bedrooms (loft, two-storey) deliver strong ROI. Single-storey rear extensions that just enlarge the kitchen deliver weaker ROI (8-12%). If you don't need bedrooms, spending £45k on magnificent kitchen beats spending £80k on kitchen-diner extension with marginal space gain.

When Extension Is the Smarter Choice

1. Your Kitchen Is Undersized (<12m²)

Victorian terraces often have 8-10m² kitchens. No amount of premium units fixes the fundamental space problem. Modern family buyers expect 18-25m² kitchen-diners. If you're below 12m², extension is necessary, not optional.

Rule of thumb: If you can't fit table + 6 chairs in your kitchen, or your kitchen+dining rooms combined are <20m², extension will deliver stronger ROI than kitchen renovation alone.

2. You're Staying 5+ Years

Extensions take 3-6 months and cause major disruption. Only worthwhile if you'll enjoy the benefit for 5+ years. The lifestyle improvement (bigger living space, indoor-outdoor connection, more light) compounds over time and justifies the investment even if ROI is 95-105%.

  • Year 1-2: Extension feels expensive vs benefit
  • Year 3-5: Lifestyle benefit equals cost
  • Year 6+: Extension pays for itself through avoided moving costs + ongoing enjoyment

3. Property Value £600k+

On higher-value properties, extension ROI improves significantly. £80k extension on £700k home adds £91k+ value (115% ROI). On £500k home, same extension adds £60k (75% ROI). The percentage value increase scales with property value, making extensions increasingly attractive above £600k.

£500k Property

£80k extension → £60k value (75% ROI)

Kitchen better choice

£900k Property

£80k extension → £117k value (146% ROI)

Extension better choice

4. You Need Bedroom(s)

Two-storey extensions or loft conversions that add bedrooms deliver 15-20% value increases vs 10-12% for single-storey. Adding a bedroom fundamentally changes your property's market positioning (2-bed → 3-bed jump is worth £100k+ in many London areas).

If you need both extra kitchen space AND another bedroom, two-storey extension (£95k-130k) is far better ROI than separate kitchen renovation + loft conversion.

5. Rear Garden Is Oversized

If you have 20m+ rear garden, losing 6-8m to extension still leaves substantial garden. Buyers prefer balanced garden:house ratio. 12-15m garden is more useful than 20m+ for most London families. Extension makes sense when garden is larger than needed.

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The Combined Approach: Best of Both Worlds

The highest ROI strategy is often: modest extension + mid-range kitchen. Add essential space, but don't over-specify on either element. This balanced approach maximizes value without overcapitalizing.

StrategyCostWhat You GetTypical ROI
Luxury kitchen only£45k-50kGerman units, premium appliances, designer finishes in existing space120-160%
Basic extension only£75k-85kGood-size extension (18m²), IKEA/Howdens kitchen, standard finishes90-115%
Modest extension + mid-range kitchen£75k-85k15m² extension, quality high-street kitchen (Howdens/Magnet), good finishes130-150%

Optimal Combined Approach Budget Split

For £80k total budget, the optimal split is:

Extension Structure

60% of budget

£48,000
  • 15m² single-storey extension with good-quality structure
  • Bi-fold or sliding doors (not budget models)
  • Underfloor heating, good lighting, quality flooring

Kitchen & Finishes

30% of budget

£24,000
  • Howdens/Magnet quality units (not IKEA, not German premium)
  • Quartz worktops, mid-range appliances (Bosch/AEG)
  • Good design, well-executed layout

Professional Fees & Contingency

10% of budget

£8,000
  • Architect/designer: £3k-4k
  • Structural engineer, building control: £2k-3k
  • Contingency for surprises: £2k-3k

Why this works: You're not compromising on either element. The extension provides genuinely useful extra space (15m² = significant kitchen-diner), while the £24k kitchen budget delivers quality finishes that buyers expect. Avoid the trap of £95k extension + £5k IKEA kitchen (looks cheap) or £45k German kitchen in cramped 12m² space (wasted money).

Decision Framework: Which Option Is Right for You?

Choose Kitchen Renovation If:

  • Current kitchen is 15m²+ (adequate size)
  • Budget is £40k-50k (too little for quality extension)
  • Selling within 2-3 years (kitchen ROI faster)
  • Planning permission would be difficult/expensive
  • Can't handle 3-6 months of construction disruption

Choose Extension If:

  • Current kitchen is <12m² (fundamentally undersized)
  • Budget is £75k+ (can afford decent extension + kitchen)
  • Staying 5-10+ years (long-term lifestyle benefit)
  • Property value is £600k+ (extension ROI improves)
  • Need extra bedroom (loft/two-storey extension)

Do Combined Approach If:

  • Kitchen is 12-15m² (marginal - needs modest size increase)
  • Budget is £70k-90k (sweet spot for balanced approach)
  • Want maximum ROI (130-150% typical)
  • Need some extra space but can't justify £85k+ extension
  • Timescale flexible (selling in 3-5 years)

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Frequently Asked Questions

Does a £50k kitchen really add 10% to property value?

It depends on your property's value and existing kitchen condition. On a £700k property with dated kitchen, a £45k-50k renovation typically adds £70k-80k value (10-11%). The key is not over-capitalizing: don't spend more than 5-7% of property value on kitchen.

Can I do kitchen renovation first, extension later?

Yes, but it's expensive. You'll pay for kitchen installation twice. Better approach: if extension is likely within 3 years, do basic kitchen refresh (£5k-8k) and save proper kitchen budget for post-extension.

Should I extend even if ROI is only 90%?

If you're staying 7-10+ years, yes. The 10% loss on paper is offset by avoiding moving costs (£15k-25k), staying in preferred location, and years of enjoying better living space. Only problematic if selling within 3 years.

Summary

Kitchen renovations deliver better ROI percentages (120-160%) than extensions (90-115%) but add less absolute value. Extensions make sense when space is genuinely inadequate (<12m² kitchen) or property value is high (£600k+). Kitchen-only works best when space is adequate but finishes are dated, or budget is £40k-50k.

Optimal strategy for most: Combined approach with £70k-90k budget. Allocate 60% to extension structure, 30% to kitchen/finishes, 10% to fees/contingency. This delivers genuinely useful extra space without over-capitalizing on either element.

The decision ultimately depends on: current space adequacy, budget, timeline, property value, and how long you're staying. Use the decision framework above to determine which path suits your specific situation.

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Last updated: January 2025

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