This paper discusses how to map between Semantic Resources (SRs) specifically created to represent knowledge in the Construction Sector and how to measure and assess the quality of such mappings. In particular results from the FUNSIEC project are presented, which investigated the feasibility of establishing semantic mappings among Construction-oriented SRs. The paper points to the next lines of inquiry to extend such work. In FUNSIEC, a Semantic Infrastructure was built using SRs that were semantically mapped among them. After the positive results from FUNSIEC, the obvious questions came up: how good are the mappings? Can we trust them? Can we use them? This paper presents FUNSIEC research (approach, methodology, and results) and the main di-rections of investigation to support its continuation, which is based on the ap-plication of fuzzy logics to qualify the mappings produced.