Also at TBC is the #Retrofit24 exhibit, which I *think* I've mentioned before but some of the displays seem to have changed since I last popped through. That shows various examples and aspects of retrofitting buildings rather than demolition and new build. These including environmental considerations (lower carbon emissions through refurbishment) but also cultural if a building has a historical element and heritage of the location.
Sometimes (e.g. Houlton School https://www.houltonschool.org.uk/) it's possible to completely transform a building to a vastle different use.