Roughly 10 000 m² of lightweight concrete walling has been used for the conversion of an office building into affordable residential rental accommodation in Constantia View, Randburg. The Q-blocks are roughly 25-30% of the weight of brick and mortar, reducing loads by 1 ton per 5.5m² of walling at 100mm thick or 180kg per m². Each Q-block is the equivalent surface area of nearly 7 standard bricks making it in the order of 5 times quicker to lay. The Q-block quality was important as no plaster was used on the walling.