It looks to me like the recipe for creating a hardened brick wedge foundation is wrong. For all the other building foundations that come with the base game (i.e. no DLC building pieces) the wedge foundation requires more of the 1st material than a wall piece of the same type (i.e. a sandstone wedge piece takes more sandstone than a sandstone wall piece). This isn’t the case for the Hardened Brick Wedge Foundation it requires the exact same amount of materials as the Hardened Brick Wall.
Just thought you should know.