Home Equity - When can I apply?

[Frank Apap]

Here is my situation. About a year ago I purchased a "tear-down" home and started new construction (we'll call this new home). I've been funding the new construction using a HELOC on my current home ("old home"). At the end of this week I will be selling/closing on the old home, making the HELOC go away. The new home will have an approximate value (when complete) of about 700k and a mortgage of about 250k (the original purchase price).

Now, for my question, I plan to take a HELOC (or loan) on the new home to finish the construction, pay back some bills etc. How early can I apply for the HELOC/HEL? Does the new home have to have its final CO? The home is about 80% complete, but isn't fully livable yet - but from a value standpoint as-is its worth at least 550 by my estimate. I'm only looking for a loan of about 100k.

Thanks for any/all advice.