in a jurisdiction where a building code applies, because these circumstances routinely require a permit. The plans are subject to review for compliance with current building codes as part of the permit application process. Generally, building codes are not otherwise retroactive except to correct an imminent hazard. However, accessibility standards – similar to those referenced in the model building codes – may be retroactive subject to the applicability of the Americans with Disabilities Act (ADA) which is a federal civil rights requirement. Alterations and additions to an existing building must usually comply with all new requirements applicable to their scope as related to the intended use of the building as defined by the adopted code (e.g., Section 101.2 Scope, International Building Code, any version). Some changes in the use of a building often expose the entire building to the requirement to comply fully with provisions of the code applicable to the new use because the applicability of the code is use-specific. A change in use usually changes the applicability of code requirements and as such, will subject the building to review for compliance with the currently applicable codes (refer to Section 3408, Change of Occupancy, International Building Code – 2009). Existing buildings are not exempt from new requirements, with the IBC publishing a Building Code for existing buildings. Existing Building Codes are intended to provide alternative approaches to repair, alteration, and additions to existing buildings. At minimum, this ensures that any new construction maintains the current level of compliance or are improved to meet basic safety levels. Although such remedial enactments address existing conditions, they do not violate the United States Constitution's ban on the adoption of ex post facto law, as they do not criminalize or seek to punish past conduct. Such requirements merely prohibit the maintenance or continuance of conditions that would prove injurious to a member of the public or the broader public interest. Many jurisdictions have found the application of new requirements to old, particularly historic buildings, challenging. New Jersey, for example, has adopted specific state amendments (see New Jersey's Rehabilitation Subcode) to provide a means of code compliance to existing structures without forcing the owner to comply with rigid requirements of the currently adopted Building Codes where it may be technically infeasible to do so. California has also enacted a specific historic building code (see 2001 California Historic Building Code). Other states require compliance with