Pre-fire sunken property appraisal

Hi all,

I’ve got an appraisal question. The subject property is a single family pre-fire brick build in Pilsen that was originally built as a 2 story home on a slab. Both floors have 9 ft ceiling height. The parcel is “sunken” with raised front street and back alley. Access front door from street through stairs to the second floor. The upper level is designed as the living space with some bedrooms and there are 3 bedrooms on the lower level. No part of the lower level is below ground compared to the parcel level. But it is below street level. I know in multi family buildings of this kind the lower level apartment is usually legal. But I’m wondering if the lower level will appraise as GLA in a single family. The lower level is currently only partially finished but the plan is to finish it the same way as the upper level. Although single family homes are rare in Pilsen, I’m guessing since this is common here there must be an appraisal standard for these sunken single family builds?