if you have a armor games account, which you obviously do, it SHOULD auto save your building.... i enjoy Corporation Inc alot and ive never had an issue with my building being gone...
If you delete your cookies and/or cache it may delete your saved progress. But if this game saves the data to your account then you shouldn't be having a problem.
Make sure that your settings are not set to clear your cookies and cache when you close the browser. I had that problem before and that was the problem.
