There has been a longstanding concern among construction scholars and practitioners in classifying construction innovations, whether as “incremental” or “radical,” “technological” or “organizational,” “product” or “process”. In this paper we extend this interest in classification to examine what classification work accomplishes within construction innovation practices. Instead of addressing the validity of innovation categories as objective representations we explore how innovations are classified within everyday interactions that shape how they proliferate. Our approach is informed by socio-material theories of classification, communication and innovation, particularly those from Actor-Network Theory (ANT) and Ventriloquial Analysis (VA). Empirically, our approach is developed through an analysis of how a single innovation–a large format concrete block–was classified within a single warranty approval meeting as it entered the UK housing market. Our analysis explains how such classification work is dynamically constituted by formal and informal classificatory acts that involve displacements of human agency that shape how construction innovations proliferate. Classification work is thus shown to make a vital difference to how construction innovation is accomplished and can be understood. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.