Lot split financing and impacts on existing mortgage:

[Abraham Gebrezgiabhier]

Currently I own a property in Sacramento with enough backyard lot that has Alley access and my current Mortgage is at a 2.5% rate and don't want to touch or affect it.

I am in the process of considering a lot split with a plan to build a new doublex unit in the split lot with hard money or a construction loan. 

The plan is to refinance the new unit separately immediately after completion and pay back the loan. 

My question is does the lot split affect my current mortgage? Am I required to refinance my current mortgage if I split the lot?