Traditional trades (known also as traditional building trades and preservation trades) is a loosely defined categorization of building trades who actively practice their craft in respect of historic preservation, heritage conservation, or the conserving and maintenance of the existing built environment. Though traditional trade practitioners may at times be involved in new construction, the emphasis of the categorization is toward work on existing structures, regardless of their age or their historic value, with a specific interest in replication or conservation of the original results and craft techniques.