Many a property owner has bought a "3-family" only to find out later that it was actually legally only a 2.Legal use is determined by the building department, not the tax assessor, so you can't go by the # of units you see on the assessor website.

Some have never been down to the buildings department.

Your local city or county departments is usually the best place to start your research before you contact contractors.

Ask to speak to their commercial lending department, and then ask if they do commercial loans on residential properties.

However if you show the appraisal to your loan officer or the buyers loan officer they can run it by their appraisal department to see if it looks good to them. 

Currently our acquisitions depart is buying over 8 properties a month!

But you definitely want to talk to the building/zoning department prior to assuming anything.

I ended up taking an entry level position doing graphic work for a retail real estate department.

. - Certificate of occupancy—Sale or conveyance of title.If the inspection reveals violations of the City Code, excluding "life-safety" violations, as determined in the sole discretion of the code enforcement department, the subject property may be issued a "temporary certificate of occupancy" to permit the property owner to remediate said violations while occupying the property.

I attend more fundraisers for sick children, family who's home burned, raffle for fire departments than I can possibly remember in a month.That being said when my company/business "gives back" it is to a 503c compliant organization that I can claim on taxes.