Abstract: A method and system for use in forming arched openings in both concrete block and wood frame building construction. In block construction the present invention provides for the use of monolithic plant pre-cast and reinforced concrete header and arched filler combination units that is load-bearing, and in wood frame construction the present invention provides for the use of non-load-bearing pre-formed arch-filling members that could be made from recycled plastic attached to or including a lintel for overlaying the surrounding wall frame. Use of the present invention would eliminate the need for labor-intensive post and beam type headers with a site-built wooden arch and thereby reduce the on-site costs currently associated with site installation of windows and doors having an arched upper perimeter. The materials from which the present invention is made would determine its load-bearing capacity.