How to mitigate the risks involved with redesign effecting SEO?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Jim Munro: Welcome, Shannon. I do not have a lot of experience in this area but the first mitigation rule I can think of is to check whether the url architecture will change. If so, prepare a full link redirection list, implement, and keep original urls online as long as possible. Canonicalise both old and new url`s to the new urls.
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  Jim Munro: Welcome, Shannon. I do not have a lot of experience in this area but the first mitigation rule I can think of is to check whether the url architecture will change. If so, prepare a full link redirection list, implement, and keep original urls online as long as possible. Canonicalise both old and new url`s to the new urls.
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  Delah Gomasi: Make sure URL structure is the same and ideally headings & content.
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  Cody Sharp: I`ve done several hundred redesigns and always follow best SEO practices.
  
  All of this is good advice. I would also just set expectations that typically there is a downturn in traffic after an initial web design launch but generally it doesn`t last longer than a month or so. If done well, the web design will not only bounce back traffic but gain. The bounce can take longer depending on the type of website platform transition. Older platforms like asp and .net websites will take a bit longer when switching to WordPress (even when following best practices) but in the long run will be worth it as they are much more difficult to maintain and update.
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  Shannon Bain: Thank you everyone this is so helpful. The current site is already on WordPress and would be rebuilt on the same hosting however we are looking to move to the Divi theme and my biggest concern with this is the site speed going down, not sure if any insight on this...? The current design is very text heavy and not many visuals components at all.
  
  So I would just make sure all content, heading, content, URL structure remains the same and it should be ok? Is the overall `domain authority` or anything get effected? Or does google not really notice that anything has changed in that respect if it is still the same primary domain name? (This is probably a really dumb question) lol
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  Matthew Drake Shockey: Shannon Bain you should be good. I’ve transitioned dozens of Wordpress websites to Divi. As long as you double check the above, there shouldn’t be major issues.
  
  Depending on your industry, site speed would be the biggest issue with the Divi Builder. You may want to consider switching to Oxygen Builder.
  
  You are more than welcome to send me a live & dev link if you would like a second opinion. As long as the number of pages is below a 200, I wouldn’t charge you.
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  Shannon Bain: Matthew Drake Shockey that is so kind of you, Matt thank you so much. I will send you some links now to get your opinion.
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  Matthew Drake Shockey: I sent you a friend request. Messages typically don’t show up unless we are friends
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  Sam Mah: Shannon Bain, if you worry about site speed, I recommend you upgrade to a dedicated server. This type of server is better for SEO.
  
  Whatever you do during the redesign, keep the old filename.
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  Asad Awan: Make sure the URL structure, Meta tags and existing content will remain the same.
  If redesigning a site on a different CMS, please add 301 redirection on all the old URLs to the new ones.
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  Rienzi Mosqueda: On top of everything mentioned. Make sure non visible components of SEO are in one piece. Make sure to do it on a staging environment first and a senior web dev supervising the migration.
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  George G.: I would add to keep the internal urls in place. This can tank your site if not done right.
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  Shannon Bain: Thank you for everyone’s input but there is a bit of conflicting info. Is there anyone here that would be experienced and willing to work with me on a coaching basis for this project to ensure I can do this right?
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  Ammon Johns: Anything that changes the code, even by a few bites, has the potential to change the rankings. That, of course, ensures you`ve retained all the original URLs precisely. Any change to a URL is a completely new entity to the search engine.
  
  Things around a design that can help include minimising the code to content ratio (leaner delivery of content); combining CSS and JS into fewer, external files (rather than inline code) since this gets cached between page views making the site feel faster, and potentially improve the UX thereby; and of course, improvements to the Navigation, although here beware of how you unconsciously promote or demote the relationship between, or importance of, pages if you change the navigation links.
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  Ammon Johns: One tip for all designers is to clear the cache on their smartphone, go where they have a middling signal strength and are not tethered to wifi, and THEN test the site-speed. Because that is how a growing number of users may first encounter your website.
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  Shannon Bain: What if I just installed the divi builder onto the current site and redesigned the website page by page and assessed traffic as I go along? Do you think that would be effective?