Here's how to unlock the Multi-Story Base upgrade in Grounded

[Windows Central]

Building your first base in Grounded can be a tall order in the best of circumstances, with all the numerous insects who would rather you became their meal in Grounded. This is even more true if you haven't unlocked Tier II of building parts, the Multi-Store Bases upgrade. This vital upgrade unlocks floors and stairs for players, which is imperative for building homes with multiple levels or to elevate your primary source of protection.

Full story from the WindowsCentral blog...