This paper introduces the initial findings from an ongoing buildings archaeology research project. I present the results of two wide-ranging mortar surveys which describe the archaeological evidence for lime mortars within the 12^th-century bicameral chapels of Atlantic Scotland and pre-Reformation chapels of the Western Isles. The diverse evidence for materials, plan form, and structure suggest important processes of cultural negotiation. I argue that lime mortar was an animated technological agent for Christianization, which enabled power and perspective to be mediated by complex culturally appropriate techniques.