House and Fourplex on same lot

[Corey Brindle]

I'm currently in the due diligence period for buying a house and fourplex on the same lot. The fourplex is basically in the backyard of the house. I would've liked to buy just the fourplex, but the seller would not separate the properties so I bought both the house and fourplex. Right now, I see I have two options. Keep the house and rent it out. Option 2, Survey the house off the land and sell the house separately, and I'll keep the fourplex. I would like to do option 2, but I am unsure of how the process works with a mortgage attached to it. The current mortgage would be for both the house and fourplex. If I sell the house, will the money from the sell go back into the total mortgage, or when I get the house surveyed, does that trigger a refinance and create two mortgages? I'm not sure how it works so any help would be great.