A Walloon entrepreneur developed and patented Cimorné cement render at the beginning of the 1930s in Braine-l’Alleud (south of Brussels, Belgium). This peculiar façade finish consists of a pigmented multilayer cement mortar onto which opalescent and mass coloured glass granules were projected. Cimorné became popular in the interwar period and was available in a variety of (very bright) colours, depending on the global hue of the added opalescent glass granules. Local craftsmen developed in their characteristic manner application techniques, mixing the mortar of the cimorné render, based on a Portland cement mortar, on-site. Minor information is available about the cimorné technique, a regional applied finish of which the characteristics, formula and application method were mainly orally transmitted between craftsmen. Hence, knowledge about the cement mortar, its cement-sand ratio, granulometry, etc. is crucial and prior to durable repair and restoration campaigns. Interviews with retired plasterers revealed relevant information about the original formula, preparation on-site and application method. The information related to the cimorné craftsmanship was compared to data found in archival records, patents and interwar plastering and masonry manuals on the one hand and to results from laboratory analyses of mortar samples lifted on-site on the other hand. The overall results form the basis for restoration trials, which will be carried out on-site, in order to enable future durable and sustainable repair interventions of this peculiar Art Deco cement render.