Chapter 2 - Site Consolidations/Mergers

Managing a full website migration through to completion, whilst mitigating any significant decreases in traffic and visibility, is an exceptionally complex task. When it comes to website consolidation/merger projects, a lot of the tasks undertaken will be the same as for a typical website migration however there are a few key tasks that need to be considered and prioritised. 

At Semetrical, we undertake a number of website migration projects a year and recently have been spending a lot of time supporting clients with large scale website consolation projects. The 7 tips discussed below have underpinned our successful approach to these types of migrations. They include:

Tip 1: Audit all websites involved in the project

Tip 2: Find the corresponding URLs & missing pages between websites involved

Tip 3: Decide which URLs do not need to be migrated

Tip 4: Signpost to users why they are being redirected

Tip 5: Build a page to rank for branded search queries of the merged sites

Tip 6: Identify keywords gaps between the old URL and the new URLs 

Tip 7: Have patience when the website merger goes live

1. Audit all websites involved in the project

In the pre migration phase of a merger or consolidation project, you should undertake audits of all of the websites involved, This includes the parent website (the website which all other domains will be merged into), alongside auditing the other domains that will be migrated. 

Audit the parent & migrated domains: 

You want to make sure that the main domain has strong technical foundations. This will be  the domain that search engines will be reviewing once all websites have been merged so it is really important to undertake a thorough technical audit of the parent domain. The main areas of review should be identifying and fixing:

  • Crawlability issues, such as a poor crawl path
  • Duplication of URLs, such as duplication content or parameter based issues
  • Speed issues, such as slow server response times
  • Web vital scores to make sure the domain is future proofed
  • Bugs that the developers are not aware of

The migrated domains should also be audited to ensure that no technical issues are migrated across to the parent domain and crawlability issues are addressed. These audits do not need to be as in depth as the parent domain review but it is good to know what issues you are dealing with when merging multiple sites.

Historical penalty analysis

When merging websites, some of the  websites you are dealing with could have historically had a penalty which has caused a traffic drop. If you merge these websites into the new parent domain, those penalties could be transferred across, so it is important to review the Search Console accounts of these websites to see if there has ever been a penalty. In addition to this, we also recommend reviewing historical traffic trends in Google Analytics and third party tools to see if any significant traffic drops align with updates.

Disavow file analysis

It is important to identify all of the disavow files that are present across all of the domains and cross reference the migrated websites’ disavow files to the parent’s. When undertaking this analysis you are ideally looking to identify domains that are not included on the parent domain’s disavow file but are included on the other websites’.

Once you have identified the domains that are missing, combine them with the pre-existing disavow file and re-submit it in Google Search Console.

Once you have merged domains, low quality links that pointed to the other domains will now be pointing to the parent domain, so updating the disavow file will make sure Google will dissociate those low quality links with the new parent domain.

Ben Beckwith

Head of SEO at Semetrical.

Ben Beckwith joined Semetrical back in 2014 as one of the first employees and has since grown with the company where he is now Head of SEO. He has developed an award-winning department of SEO specialists at Semetrical and is passionate about all things SEO. Ben is an experienced SEO strategist, having a strong focus on technical SEO, website migrations, and user intent, implementing successful campaigns for clients such as OnTheMarket, Beano, JPI Media and Lexis Nexis. To keep Ben busy over the pandemic, he bought his first house and completely renovated it just in time for him and his wife who are expecting their first child in early May.

Watch our Tea Time SEO session here:

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2. Finding the corresponding URLs & Identifying missing pages

In the pre-migration phase of the project you will need to identify the URLs that can be mapped 1 to 1 where similar content exists on the parent domain. This is a critical step and can be quite time consuming. At Semetrical, we will usually map URLs from one site structure to another by:

Matching on URL structures

The end path of a URL can be the same from one website to the other. This is especially common when merging websites in the publication space where a lot of the content can be syndicated. For example, the elements highlighted in red are the same from one site to the other:

Matching on heading and title tags

The H1s or title tags of a page can be the same or very similar from one site to the other, for example:

<title>NHS chief confirms staff were promised higher pay rise</title>

Matching URLs ranking for the same keywords on page 1

If you are struggling to match on URL structures or metadata then matching on keyword rankings can be super useful. For example, if you download a search query report from Search Console along with URLs and cross reference the search query reports from website A and website B you can isolate the keywords where both sites are ranking on page one.

Once you have isolated the cross over of search queries, you then can identify the URL ranking for site A and the URL ranking for site B. The end result is a list of URLs that can be mapped to each other.

Matching using a similarity web crawler tool

A similarity web crawler can be your answer if you are struggling to map URLs to a relevant alternative destination when merging one website into another. At Semetrical, we have built our own similarity tool which can crawl two sites in full and group URLs together based on how similar the page content is. For example, if you set the  similarity score to 85%, the crawl report will only show you the URLs grouped together that are 85% or higher in similarity..


There are other crawling software out there that have a similarity feature built-in which can do something very similar.

There will however be many situations where it is not possible to map a URL from one site to another. In this situation you should identify the pages that cannot be 1 to 1 redirected and provide a list of pages to be recreated on the new website to your development team, along with information on where it should be housed in the website hierarchy.

3. Not all URLs need to be migrated

A website merger gives you the opportunity to clean up content and remove redundant or low quality pages so you don’t have to migrate every page over. Instead you can 404 or 410 these pages.  The criteria to use when evaluating whether  a URL should be migrated over or not includes:

  • Has the URL received consistent traffic in the past 12 – 18 months?
  • Has the URL generated enough traffic that it’s a priority? 
  • Has the URL built up authoritative backlinks? 
  • Has the URL received seasonal traffic spikes?
  • Has the URL been deemed a priority to the business?

If the answer is NO to all of the above then most likely the URL does not need to be prioritised and migrated over and instead can be killed off.

4. Signpost to users why they are redirected

When merging one site into another it is really important that you are considering the user journey to ensure that your customers don’t have a “Where the hell am I?” moment! If a customer goes to site B but lands on site A it could be very confusing and disorientating for them, especially if it is not clear  why this has happened. Below are a few ways in preventing this happening:

  • Create a JavaScript overlay when a user is redirected – this is great for mergers but also when you are rebranding
  • Add a message on-page to say “content was originally from X”

5. Rank for for branded search queries of the merged sites

Make sure the new website is still visible for the old site’s branded keywords as customers will still search for the branded keywords of the sites that have been merged into the parent domain. It is also important to monitor the branded keywords and SERPs of these websites for a period of time following the merger. A couple of ways to stay visible include:

  • Writing an article optimised for the old brand
  • Building an optimised category or hub page for the brand
  • Setting up paid ads to indicate the original site has now moved to a new site

6. Identify keyword gaps between the old URL and the new URLs

When mapping URLs from one website to another they should be mapped and redirected to an equivalent page. However, there can be scenarios where you have a similar URL on both websites, which is great for 1 to 1 mappings, but the URL on site B is performing better than the equivalent URL on site A which is going to be the primary URL after the merger.

The URL on site B could be ranking for a wider range of keywords compared to the equivalent URL on site A, which could mean a drop in traffic following the merging of these two URLs as site A`s URL is not optimised for the other keywords.

To counteract this, once you have finalised the 1 to 1 mappings, you can undertake gap analysis between the two URLs to isolate those missing keywords which can then power a re-optimisation project as part of the migration.


The main steps to take to isolate those missing keywords include:

  1. Take a Search Console report which includes both keyword and URL ranking for each website
  2. Take your URL mapping document and bring in the keywords for both URLs (URL A and URL B)
  3. Compare the keywords ranking for URL A to URL B  and isolate the missing keywords
  4. Make sure you optimise URL B with the missing keywords that URL A ranked for

For more information on the keyword gap analysis process Semetrical have written a blog post on identifying keyword gaps between the URLs being mapped.

7. Having patience when the website merger goes live

Once you flip the switch on the website mergers and the redirects are live, it is absolutely essential that you  have patience and don’t make any rash decisions.

John Muller in 2020 mentioned that when merging websites it can take longer for Google to process all of the changes compared to a typical website migration.


The old website which has now been merged into the parent domain can stay in the Google index for a while post migration, so it can be normal to see both domains appearing on the SERPS for a period of time.

Do not attempt any quick fixes to remove the old domain from the search results as this will just hinder the success of the migration. For example, do not request the domain to be removed in Search Console or keep the old robots.txt file live with a “Disallow: / “ rule.

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