How does a firm or renovator document or confirm the age of the structure? Is a signed statement by the occupant sufficient? Can publicly available information such as tax records, etc. be sufficient?

Renovation firms are responsible for determining the age of the property.  The property owner is likely to be a good source of information on the age of a home or other building, but the firm may not rely on the statement of the property owner as to the construction date of the building if there is evidence to the contrary.  If in doubt, renovation firms can use tax assessments, property records, and similar information to determine the date of construction.  Finally, the renovation firm may always assume that a home or child-occupied facility was constructed before 1978.  

• If I am insulating a multi-family building, does the standard for interiors of 6 square feet or less of disrupted painted surface, or the standard for exteriors of 20 square feet or less of disrupted painted surface apply to the whole building or can it be applied to each separate unit?
• What is your recommendation if work under the Renovation, Repair, and Painting (RRP) Rule has started and it begins to rain? What do we do with the water that is on the plastic in the containment area?
• Does the RRP Rule apply where no paint at all is present, such as in a 100 year old unfinished basement?