Cut 2-by-24-inch strips of corrugated cardboard with a razor blade.
Glue a strip of decorative raffia along the bottom of a 24-inch edge of the cardboard with a hot glue gun.
Glue a second strip of raffia onto the cardboard above the first one, layering the straw so it lays on top of the first batch. This strip should be positioned in the middle of the cardboard surface.
Glue a third and final strip of raffia to the top of the cardboard surface, creating three overlapping layers of straw.
Staple the finished section of faux thatch to your roof with roofing staples. Position this first section at the lower edge of your roof.
Create additional sections of faux thatch and staple them to your roof. Begin by lining the lower edge of the roof, then add the next layer 12 inches higher to create a layered surface.
Continue adding sections until the roof is covered.