An apparatus and method for sealing a grout space provided between a backing wall and a veneer layer. The grout space sealing apparatus includes a deflector that is installed at an intersection of a backing wall and a horizontal surface and a sealing member that is positionable over the deflector and extends onto the backing wall above the deflector and/or across the horizontal surface in front of the deflector. The grout space sealing apparatus causes water that has permeated the exterior veneer to run down an exterior surface of the sealing member. The water is directed along the exterior surface of the sealing member away from the backing wall and towards weep holes provided in the veneer.