I bought a commercial property with a large down payment and a carry by owner contract. Renovation costs are covered by other funds, my salary, grants, sponsors, etc. A lot of the renovation is just sweat equity: us doing the work in our spare time.

We found that unless the commercial property is occupied already with a revenue stream, loans from banks weren't likely. There are private loans out there. There are also hard money lenders that can loan enough to acquire property, then you renovate and occupy it, with the idea that you will qualify for a traditional loan to cover the hard money lender quickly. The hard money loans are interest-only, short term loans (like less than two years).