If I have a Folder called Reporting and a Folder called Human Resources and both folders use a Custom column (was created at the Site Collection level) called Business Classification. Can I create a Search across both folders using this column (Business Classification) as a search filter ?
Note both folders are within the same Team site.
You can create a new managed property connected to your custom column. First go to the Farm Administrator to check if "Business Classification" is already crawled:
If so, go to Managed properties and create a new property with the name: "BusinessClassification" and check the Queryable and Retrievable checkboxes. Map the previous found property to it (Mappings to crawled properties), this probably starts with ows_.
After adding the property Start a full crawl. When this is done we can add the new property as refiner to search. Edit the search refiner web part and add the "BusinessClassification" property to the list of refiners:
Also this article contains a good overview how to do this: https://www.credera.com/blog/technology-insights/microsoft-solutions/search-enjoy-sharepoint-2013-custom-search-faceting/
