A method and device are presented that creates a channel adjacent a nailing flange of a window in between the window and the rough opening that receives the window. The channel is created by establishing a barrier that prevents foam insulation inserted into the space between the window and the rough opening from reaching the nailing flange. The channel then ensures proper drainage of water that enters the window cavity down to the window sill. A gasket is presented that can be attached to the window or the rough opening to create the barrier. Alternatively, a disintegrating object or a wicking object can be used to impede the flow of insulation foam and to create the appropriate channel. The present invention is equally applicable to doors or other framed objects received into the exterior shell of a building.