Offer price valuation with lots of renovation

[Joe Joseph]

Looking for assistance to analyze a Mixed Commercial building that has three sections and it used to be a bank. It's one building and all is connected. It sat empty and not used for 10 years. 

Section One: The bank, long and narrow 30ft ceiling and has a basement.

Section Two: Three story office building and has a basement. 

Section Three: three story apartments loft style. Inside need to be totally renovated. It's long, narrow and Empty. The basement made it a three story,  it's really 2 story and a basement. 

The basements will be used for storage only.

Rental in the area is about $12sf. But the sale price is equivalent to $25sf.

My main question is how much dollars should I offer per square footage if the building was in ok condition? And how much should i offer given the whole building need renovation, some parts more than others?

it's more of a redevelopment project.

I'll pay if need be-