Help me with the math please and help with diversification

[Chris Wallace]

I am the sole member of an LLC that owns a B&M building and lot. I like the building, lot, location etc. I'm not really interested in selling.

Single tenant commercial NNN lease.

Rent $10,400 per month.

Last appraisal was in 2014 @ $1.8M

Tenant is in year 3/5 of current lease with a right to buy option until end of year 5.  

Auto renewal terms in place for up to two 5 year terms.  

Current rent increases 2% per year.

What I don't like is 80% of my net worth is in this one property.

I'm considering options to take a loan against the property to either invest in another property or maybe something else entirely.  One example of a loan would be 10 year fixed interest loan at 5%.  I could borrow 1M and payment would be $10,600/month roughly.  Add some for loan origination fees, etc.  In other words, the rent roll would effectively pay for the loan and be paid in full in 10 years.  Leaving me with the property lien free assuming everything goes as planned.  With the 1M in cash, I would need to invest in something else to make up for the loss of rent that I currently enjoy.

Math question, how much interest would I need to earn to make this strategy worthwhile?
Assumption here is the 5% as it's been a couple years since I have considered any loans.  I don't have any other debt.  Modest paid off home.  Paid off vehicles, etc.

Your advice is appreciated.

Chris