stairs are attached to the building. It is co-owned and I cannot imagine the situation where the stairs and landings wouldn't either be the property of one party, or common property for all to use- in which case you can partition its proportionate cost with the land, driveway, etc. Small isn't it? BUT, the common areas "in use" are generally not fungible items. They cannot be sold for their intended purpose.
I believe we call that "value in use" and "insurable value" would be the cost to replace a burned or damaged staircase. This is a cost issue, not an independent sales (market) issue. And the first question is this an item owned by the POA as a whole? Or co-owned by the occupants?