Fire separation distance. Do exterior finishes need to be rated?

[Question That]

Have a situation where building (cmu on slab with undetermined type of siding, metal roof etc) and the building is less than 5' from property line as measured perpendicular to the building to the line. Building is 45 degree angle to the line so not sure how that factors in but the closest point is as stated above.
It's my understanding that I need to measure to a "lot line" and not sure of the distinction between lot line and property line for code purposes.
Note that this particular property line does not have any adjacent buildings. Another corner of the building is 30' from an adjacent building that sits directly on the property line.

My understanding would be that for type IIB assembly occupancy that this wall would need to be 1 hour rated and rated for both interior and exterior exposure.
Shouldn't be a problem because cmu but I don't understand how the exterior finishes come into play. Brick to water table height then siding above.
Does the siding become a factor or is it just the structural portion of the wall?
Anything else I need to consider?

 

[jc_ks]

How have people been addressing possibly combustible insulation/finishes on walls that are pretty fire resistant by their nature (concrete/CMU)?

 

[mtlogcabin]

Read IBC Section 1405 completely

1405.1.1 Types I, II, III and IV construction.
On buildings of Types I, II, III and IV construction, exterior wall coverings shall be permitted to be constructed of combustible materials, complying with the following limitations:

1. Combustible exterior wall coverings shall not exceed 10 percent of an exterior wall surface area where the fire separation distance is 5 feet (1524 mm) or less.

2. Combustible exterior wall coverings shall be limited to 40 feet (12 192 mm) in height above grade plane.

3. Combustible exterior wall coverings constructed of fire-retardant-treated wood complying with Section 2303.2 for exterior installation shall not be limited in wall surface area where the fire separation distance is 5 feet (1524 mm) or less and shall be permitted up to 60 feet (18 288 mm) in height above grade plane regardless of the fire separation distance.

4. Wood veneers shall comply with Section 1404.5.