We have a 90 year old poured concrete unfinished basement with no insulation to speak of. I really like working with Reflectix insulation and I spotted this PDF: [url]https://cdn.shopify.com/s/files/1/0273/9961/8634/files/Crawl_Space_-_Under_Joists.pdf?v=1583848410[/url] I know this is for a crawl space. But what are the arguments against doing this in a basement? Thanks!

First time posting on here, so forgive me if this is addressed on another thread. I am purchasing a home in Colorado Springs. The previous homeowner finished the basement themselves without a permit and never got it inspected (although it looks like good work in general). I want to file the permit and get everything approved. However, it appears they did NOT float any of the walls. So, I have two questions: 1. What is the best way to convert the existing walls into floating walls? 2. Do the perimeter walls have to be floated (there seems to be differing opinions) to pass inspection, or just interior walls?