A hinge support includes a brace, a trestle, and a positioning device. The brace includes a base wall and a first side wall, a second side wall, and a positioning wall that extend from the base wall. The first side wall has a first sloped surface, and the second side wall has a second sloped surface. The trestle includes a top wall and a third side wall, a fourth side wall, and a support wall that extend from the top wall. The third side wall has a third sloped surface, and the fourth side wall has a fourth sloped surface. The positioning device is supported by the support wall and positioned to abut the positioning wall to mount the trestle to the brace. The third sloped surface slides along the first sloped surface and the fourth sloped surface slides along the second sloped surface under control of the positioning device.