ABSTRACT
The aim of this paper is to present as a case study the historical outline describing how the diffusion paradigm arose in the US beginning in the 1930s. The diffusion paradigm is the widely held understanding that hygric performance of building envelope assemblies can be satisfactorily explained by molecular diffusion as it is controlled by permeance of materials. The problem of paint peeling on the exterior of insulated buildings prompted the studies; curiously, the recommended prescriptive practices that arose from the diffusion paradigm could not address the paint-peeling problem satisfactorily. Building scientists who become familiar with the historical outline of the diffusion paradigm in the US can have better understandings of the rationale for building practices and regulations, as well as for the social, inter-professional, commercial and regulatory contexts in which building science operates.
