The verdict in three sentences
A partial redesign costs 6,000 to 12,000 EUR ex. VAT and takes 4 to 6 weeks, while a full rebuild rises to 18,000 to 35,000 EUR ex. VAT over 8 to 10 weeks. The right choice depends on three factors: technical debt, the value of the existing SEO foundation and the timeline available. If your LCP exceeds 4 seconds and the CMS is locked, rebuilding is almost always more cost-effective over 24 months.
Partial redesign vs rebuild: the decision matrix
A consulting firm lives on its online credibility and its ranking on competitive queries. Here is the 2026 numbers comparison of both options.
| Criterion | Partial redesign | Full rebuild |
|---|---|---|
| Cost EUR ex. VAT | 6,000 - 12,000 | 18,000 - 35,000 |
| Timeline | 4 - 6 weeks | 8 - 10 weeks |
| SEO risk | Low | Medium (redirects) |
| LCP gain | 4.2 s to 2.8 s | 4.2 s to < 2 s |
| Technical debt | Stays partial | Eliminated |
| Lifespan | 2-3 years | 5-6 years |
| In-house editability | Limited | Full (modern CMS) |
A partial redesign is an effective patch if the foundation is healthy. As soon as technical debt blocks changes, a rebuild becomes the most rational investment.
What technical debt really costs
An ageing site is expensive even without a redesign: slowness, bugs, inability to add pages, lost traffic. Here is the 2026 numbers impact.
| Symptom | Estimated hidden annual cost | Business effect |
|---|---|---|
| LCP > 4 s | -8 to -15% conversion | Lost leads |
| Obsolete CMS | 3,000 - 6,000 EUR/year dev | Blocked changes |
| Security flaw | 2,000 - 20,000 EUR (incident) | Reputational risk |
| No mobile-first | -20 to -40% mobile traffic | Falling SEO |
| Non-editable content | 150 - 400 EUR per edit | Vendor dependency |
Added together, these hidden costs often exceed the price of a rebuild over two years. That is the deciding argument.
Mini case study
Thomas, partner at an 18-consultant firm in Dublin, is hesitating. His site has a 4.2 s LCP and a locked CMS costing 4,500 EUR/year in dev interventions. A partial redesign at 9,000 EUR would fix neither the debt nor the slowness. He opts for a rebuild at 24,000 EUR ex. VAT that takes LCP under 2 s and removes the 4,500 EUR/year of dev. With organic traffic of 4,000 visits/month and conversion rising from 1.8% to 2.5%, he gains 28 leads/month. At 12% conversion into 20,000 EUR missions, the potential is considerable: the rebuild pays for itself in under three months.
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FAQ
How do I know if a partial redesign is enough?
If your technical foundation is healthy, your CMS modern and your LCP under 3 seconds, a partial redesign at 6,000-12,000 EUR refreshes the brand without rebuilding everything. Otherwise, rebuild.
Does a rebuild lose SEO?
Not if the 301 redirect plan is rigorous and the sitemap preserved. Done well, a rebuild even improves SEO thanks to sub-2 s LCP and clean mobile-first.
What performance gain should I expect?
A modern rebuild typically takes LCP from 4.2 s to under 2 s, improving Core Web Vitals and conversion by 8 to 15%.
How long between the two options?
A partial redesign takes 4 to 6 weeks, a rebuild 8 to 10 weeks. If you have a tight deadline, a partial redesign can be a step before a rebuild.
Does technical debt alone justify a rebuild?
Often yes: between recurring dev, slowness and blocked changes, the hidden costs frequently exceed the rebuild price over 24 months.
Let's scope your project. Send us your current site URL and your goals, and we will audit the technical debt and recommend redesign or rebuild, with figures. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
