HELOC on commercial property

[Meso Stick]

im will be starting my first construction project next month. Once done the building will consists of a commercial space and 2 residential units. My construction loan of $400K will automatically convert to into a mortgage. Im looking for a bank to would allow me to convert this $400K to a first lien HELOC with max 80% LTV. This lender won't do it, TruMark my credit union won't do it.

The appraised value will be roughly $800K+.

Any one knows a bank/credit unit will to this ?

thanks in advance

Andy