It is a good idea to check that your use is allowed by the zoning code at that particular location. If your proposed use is a prohibited use in the zone, you may need to prove the use has "nonconforming status". That means documenting that the use was allowed when it was first established and that the use has continued over time. An expansion of a nonconforming use or change to another use prohibited in the zone may require a nonconforming situation review or may not be permitted at all.
Some uses may be limited in floor area even if allowed in the zone and the other uses in a building may need to be identified to determine if the floor area of the proposed use may be allowed. For zoning information, call a planner at (503) 823-7526.