The purpose of this research paper was to explore if the adverbial phrase but at least (BAL) is a construction and if any constraints could be identified. To be able to determine a classification, the research focused on finding syntactic and semantic patterns, investigating the definition of constructions as being non-predictable and usage-based. The research was a corpus-based study, analyzing 200 tokens that were extracted from the Corpus of Contemporary American English.The tokens were analyzed by coding them by syntactic features, the semantic use of BAL and the semantics of the whole sentence. The result demonstrated that the BAL-phrase is a construction as a syntactic pattern could be determined, the semantic use of BAL indicates that it is usage-based and it incorporates non-compositional meanings. Furthermore, three constraints could be identified.