Adu financing without standard DTI

[Kessler Armbruster]

Hey guys, 

I am looking to get a loan to build an adu attachment to my house. I can not get an fha or conventional loan to pay for it because I can’t cover the dti. I have about a 78 percent loan to value based off comps. And also have my 20 percent To cover the down payment on the building costs of project. I just don’t know where to find the financing for the other 80 percent and what kind of loan do I need to look for. Any advice?