For people doing DADU strategy - how are you handling partial releases?

[Skyler Bissell]

I own my primary residence and want to build a DADU on the back of the lot. In working on construction loan financing, the lender informed me I'll need to unencumber that portion of the property (makes sense) before closing on the construction loan.

I understand there to be two methods generally speaking: refinancing my mortgage and removing that portion of the property in the process OR attaining a partial release from the lender to remove that land.

I *strongly* want to avoid refinancing as I have an amazing rate, but partial releases seem complex and also require a survey. I'm going to get a survey regardless, but I'd like to line all this up before I start spending on soft costs.

The weird thing is I see other investors doing these DADU deals and I've never heard anything mention the above requirements / scenario. 

Am I overcomplicating this? Is there a simpler way to do things? Any thoughts appreciated.