The reinforcement device for bracing a building aperture cover, such as a garage door; automatically engages when the aperture cover is lowered and disengages when the door is raised. The device employs at least one upper anchoring element, cooperating with the door header, and one lower anchoring element, cooperating with the floor structure. Both the upper and lower elements are securely attached to aperture cover so that they effectively divide and support the span of the aperture cover against positive and negative wind loads.