Short answer: List every page on your current site, map each old address to the new page that covers the same thing, set up permanent (301) redirects, and check Google Search Console after launch. Keep the same addresses wherever you can.
Why redesigns lose traffic
Google ranks individual pages, each at its own address. When a redesign changes those addresses and the old ones stop working, Google finds broken pages, and the rankings and links those pages earned don't carry over to the new site on their own.
Step 1: List every page you have now
Before anything changes, make a full list of your current page addresses. Your site's sitemap is a good start, and Google Search Console shows which pages Google knows about. Include old blog posts. They often get more visits than people expect.
Step 2: Find the pages that matter most
In Google Search Console, look at which pages get the most clicks and which searches bring people in. Those pages need the most care. Keep what's working about them in the new version.
Step 3: Map every old address to a new page
Match each old page to the new page that covers the same thing. An old "water heater repair" page maps to the new water heater page, not to the home page.
- Keep the same address when you can. No redirect beats a good redirect.
- When an old page has no close match, send it to the closest related page.
- Avoid sending everything to the home page. Google has said it may treat mass redirects to the home page as if the pages were simply gone.
Step 4: Set up permanent (301) redirects
A 301 redirect tells browsers and Google that a page has moved for good. Set one up for every old address before the new site goes live, so nobody ever lands on a broken page.
Step 5: Launch and check
Right after launch, test a handful of old addresses to make sure they land on the right new pages. Submit your new sitemap in Google Search Console. Over the next few weeks, watch Search Console for pages Google reports as not found, and fix any you missed.
- It's normal for rankings to move around for a few weeks while Google re-checks the site.
A real example
When we rebuilt the site for Phoenix Remediation & Restoration, the old site had 232 page addresses, most of them short blog posts repeating the same advice for different towns. The new site has 39 focused pages. Every old address redirects to its closest new page, so a post about water removal in one town now lands on that town's service area page, and a post about mold lands on the mold remediation page.
Common questions
Do I need to keep my old blog posts?
Not always. Thin or repeated posts can be retired, but redirect each one to the closest useful page instead of deleting it outright.
Will my rankings drop after a redesign?
Some movement for a few weeks is normal. With careful redirects and the important content kept, most sites recover.