COMPANY - COLWIS Colwis Corp. is a privately owned company, operating out of Richmond Hill, Ontario and serving the GTA and Ontario. Our services include General Contracting, Construction Management, Project Management, Design Build, Land Development, Electrical & Mechanical Subcontracting, Formwork Subcontracting and Electrical Supplies to various private, public, and government clients. Our projects range from commercial, institutional, industrial, high-rise residential and hi-rise retirement residences.