How strict are building codes?

[Alex Lee]

We are looking to move to Georgia and I was curious to know how hard/strict it would be to expand houses.

So for instance if we buy a 1700sqft house, how hard would it be to say build it out to say 3k?

For now we are considering for our residence, but as we intend on buying investments as well I thought it would be good to know what i might be getting into.