The verdict in three sentences
A redesign (keep the foundation, redo design and content) is enough when the CMS is recent, technical debt moderate and SEO healthy: cost and time halved. A full rebuild is required when the foundation is obsolete, unmaintainable or blocks evolution: more expensive, longer, but it starts on a clean base. The real risk to manage in both cases is SEO traffic loss from redirects.
Redesign vs rebuild: costs and timelines
2026 order of magnitude, France, B2B marketing site of 30 to 80 pages.
| Criterion | Redesign | Full rebuild |
|---|---|---|
| Budget | 15,000-40,000 EUR | 30,000-80,000 EUR |
| Timeline | 2-3 months | 4-6 months |
| Technical foundation | Kept | Rebuilt |
| Technical debt cleared | Partial | Total |
| SEO risk | Low to moderate | Moderate to high |
| Content overhaul | Yes | Yes |
| New features | Limited | Unlimited |
| Redirects to manage | Few | Many |
A rebuild typically costs 2 to 2.5 times a redesign, for real functional gain only if the existing site is a blocker. Don't pay for a rebuild to solve a design problem.
Decision grid by factor
| Factor | Leans redesign | Leans rebuild |
|---|---|---|
| Site age | < 4 years | > 5-6 years |
| CMS | Recent, maintained | Obsolete / unsupported |
| Performance (LCP) | < 2.5 s | > 4 s chronic |
| Technical debt | Moderate | Blocking |
| Functional needs | Incremental | New (e-commerce, portal) |
| Current SEO quality | Good, to preserve | Weak anyway |
| Security / dependencies | Up to date | Vulnerable |
Mini case study
Nadia, digital lead at a Bordeaux software vendor, is undecided. Her site is 4 years old, on a maintained CMS, LCP at 3.1 s, moderate debt, but it generates 18,000 visits/month, 65% from SEO. A 58,000 EUR rebuild would threaten that traffic through hundreds of redirects; a 26,000 EUR redesign keeps the URLs and foundation. She quantifies the risk: a 20% SEO loss over 3 months means ~2,340 visits/month × 3 lost, an estimated commercial shortfall of 9,000-12,000 EUR. Nadia picks the redesign: she saves 32,000 EUR and cuts traffic-loss risk threefold while modernizing the design.
FAQ
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Can a redesign hurt SEO?
Yes if you change URLs without a rigorous 301 redirect plan. A well-run redesign with preserved URL structure has near-zero SEO impact and often improves ranking through performance.
When does a CMS justify a rebuild?
When it is no longer maintained, has unpatchable security flaws or blocks key features. An old but updated CMS does not by itself justify a 55,000 EUR rebuild.
How do I protect my traffic during a redesign?
Map every URL, set 301 redirects, keep high-performing title/H1 tags and monitor indexing via Search Console for 8 to 12 weeks after launch.
Progressive redesign or big bang?
A progressive redesign (page by page) lowers risk but lengthens the timeline. Big bang is faster but concentrates risk: reserve it for small, well-controlled sites.
How long before redoing it again?
A well-built B2B site lasts 4 to 6 years. Budget continuous evolution (3,000-8,000 EUR/year) to push back the next heavy overhaul.
Let's scope your project. Share the site's age, CMS, SEO traffic volumes and functional needs: we will decide redesign or rebuild and cost both. 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.
