Overhanging building' Supplementary Plate - Post Mount Diagram 530.1 R2/RA2This permanent sign supplementary plate "overhanging building" can only be used in conjunction with sign faces 530A and 530. It is used to warn in advance of an area with restricted headroom for vehicles. Alternative versions of this sign feature the wording buildings, or structure. The size of the text can also be altered depending on the requirements of the road. If required an arrow or distance may be appended, if this is required please contact us