75mm Imperial Blue Solid engineering bricks have a compressive strength greater than 125N/mm² and water absorption less than 4.5%. These bricks are high strength and due to the low water porosity are highly frost resistant.
Typically engineering bricks are used to add colour or design to walls, or below the damp course (DPC).
Engineering bricks are specified for their physical characteristics and not their appearance. They have high compressive strength and low water absorption and are classified only by these properties. Their use for facing work should be avoided, as they are not subject to the same level of inspection for surface irregularities or colour variation as a facing brick. Where aesthetic performance is a major consideration, facing bricks should be used.