Thoughts on basement flats?

[David McCracken]

I'm currently looking at buying a duplex with two 1-bedroom flats. The basement has a common area as well as an unfinished setup for a small studio apartment. Plumbing and electrical is already set up for a bathroom and kitchen. This means I could potentially convert this duplex to a triplex. What are thoughts on creating a small basement flat?

The property is about 1 mile from a popular downtown area. So the demographic is really good, lots of young professionals looking to live near the action. Some potential issues that come to mind are mold and radon, but I could test for both of these and potentially remedy. Zoning is also fine to add another unit.