Sometimes, but rarely, structural....You'll need to get it into escrow and then have a good inspector take a look at it...

The plan is to demo the existing structure and build a new 9-unit apartment + retail building.

@Miranda Mayuiers To echo what Ozzy said, depending on how long you have owned your current home and the current ownership structure, you could maybe buy as a primary residence.

I recently got a notice from the city about Critical test exam report on a 3 storey porch, does anyone know a good structural engineer that can do this and how much does it cost?

Does anyone have a structural engineer they recommend working with on this project?

The property is in the flood zone or the physical structure, the home, is in the flood zone.

I'm still not entirely convinced it's possible, but it's what I'm basing all my other planning/structuring around! 

You can structure it however you and your partner wish. 

If you are looking at lenders structuring loan as a business purpose loan that would mean they also don’t follow standard Respa-tila guidelines that are standard for residential and some other commercial loans.

I had a structural engineer check out the foundation etc. out and it is structurally sound.