Window assembly comprises a wedge packing assembly and/or a deformable packing assembly for fitting between a glazing unit and a frame of a window assembly to support the glazing unit within the Frame. The deformable packing assembly comprises a base, and a plurality of elongate deformable fingers which project from the base and upon which the glazing unit is supported. The fingers are arranged in an array on the base and are adapted to, in use, bend. The wedge packing assembly comprises a first wedge element having a base surface and an inclined surface at an angle to the base surface. The first wedge element is adapted to be fitted between the glazing unit and frame along an edge of the glazing unit with the inclined surface inclined at an angle to the normal of the plane of the glazing unit and window assembly. The wedge packing assembly may then further comprise a second wedge element.