Methods and systems for making and using a wide swath offset concrete screed apparatus for screeding wet concrete slurry. The apparatus includes a cross support bar, an attachment mechanism for attaching the cross support bar to a liftable arm of a motorized vehicle, and lateral support bars for attaching a screed bar to the cross support bar. The screed bar is positioned offset from the motorized vehicle used to operate the screed, allowing the motorized vehicle to drive outside the forms.