A legal, non-conforming property is a commercial property that was legally built years ago, but it could not be newly built today on the land, as the land is currently zoned. A couple of examples will make this more clear.
Let's suppose that fifty years ago a developer built a 60-unit apartment building in downtown San Francisco with no on-site parking. Since then the City of San Francisco enacted a municipal ordinance that says every two-bedroom apartment building must have at least one on-site parking space, and every three-bedroom unit must have at least two on-site parking spaces.
This apartment building - the old one with no on-site parking spaces - does not have to be torn down. It's was legal when it was first constructed, and it is therefore still legal. However, it no longer conforms to the current city ordinances. It is non-conforming.
Here's another example of a legal, conforming building. Suppose that Florida city planners observe that stick-built apartment building adjoining the Atlantic Ocean fared particularly poorly during hurricanes. After seeing countless such apartment buildings destroyed along the coast, the city planners for most coastal Florida cities adopt an ordinance forbidding the construction of multi-family dwellings within a half-mile of the coast. Does that mean that all of the apartment building buildings along the Florida coast have to be torn down? No. It just means that they are legal, conforming buildings.
Legal, non-conforming buildings can be repaired; but if such a building is substantially damaged - say, in an earthquake or a fire - it cannot legally be rebuild.
Okay, so what? The lender will insist on a fire insurance policy, right? If the building burns down, the lender simply gets paid off by the fire insurance proceeds.
Many times this is true; but sometimes a legal, non-conforming commercial building is worth far more than its replacement cost. Absent a special endorsement to the fire insurance policy, the fire insurer will only pay for the replacement cost of the building! What if your commercial loan is much larger than the replacement cost? Yikes!
For example, this 60-unit apartment building might only cost $2.8 million to rebuild, but it might be worth $6 million (before the damage). Based on the cash flow, a reasonable commercial lender might have placed a $3.9 million commercial loan on the property. The building burns down. The insurance company hands the commercial lender a check for just $2.8 million, the building's replacement cost, because the building cannot be rebuilt. The lender has just eaten a $1.1 million loss. Ouch!
Okay, so how does a commercial lender protect himself? He obtains a special endorsment to the owner's fire insurance policy, called a ________________ (anyone know?), that pays more than the commercial property's replacement cost if the building burns down or is otherwise destroyed. This special endorement to the fire insurance policy costs around 15% to 20% more than a guaranteed replacement cost policy.
My own private money commercial mortgage company, Blackburne & Sons, will gladly finance legal, non-conforming commercial properties.