A brush seal is provided that includes a top plate, a back plate, and a bristle pack. The bristle pack is secured at a joint between the top plate and the back plate. The bristle pack includes a first bristle set extending from the joint, a second bristle set extending from the joint, and a sliding backing plate. The sliding backing plate includes a sliding portion and a support portion. The sliding portion is disposed contiguous with the second bristle set. The support portion has an inner face and a support face. The inner face is in contact with a distal end of the second bristle set. The support face is configured to support at least a portion of the first bristle set. The sliding backing plate is configured to slide relative to the second bristle set.