Precast concrete panels have great potential for walls of modern buildings. The designer must appreciate, however, that the total wall assembly must be designed as a unit to separate the internal and external conditions. In particular, the present practice of using a precast panel as both the structural unit of the wall and the external facade, with insulation on its inside face, increases the temperature range to which the panel and those items connected to it are subjected. This makes the task of achieving effective and continuing control of both air leakage and rain penetration more difficult and aggravates problems associated with thermal conditions.
A subsequent Digest will discuss a philosophy of wall design that overcomes these difficulties.