A cover layer for a vacuum wound therapy dressing includes a backing layer formed from a flexible polymeric membrane and an adhesive layer for affixing the backing layer over a wound bed to provide a substantially fluid-tight seal around a perimeter of the wound bed. The cover layer is reinforced with a reinforcement layer extending to a peripheral region of the backing layer to distribute forces associated with evacuating a reservoir, as defined by or within the cover, to stimulate healing of the wound bed.