Sustainable construction can be defined as efficient resource use with ecological design. Three pillars are required to achieve sustainable construction: environmental protection, social well-being and economic prosperity. An increase in sustainable construction awareness among industry stakeholders could help improve levels of implementation. This paper aims to assess levels of awareness among UK practitioners and identify the barriers that inhibit sustainable construction. A mixed-method approach with questionnaire surveys and interviews was adopted. Questionnaire were distributed using MS Forms through social media (e.g., LinkedIn, Microsoft Teams, WhatsApp) and the researcher's contacts. The survey concluded with 127 useable responses. Interviews were also conducted over MS Teams with eight professionals with different backgrounds. Respondents for the interview were conveniently gathered through snowball sampling. Data from the questionnaire survey were analysed using SPSS. Descriptive statistics, Cronbach's Alpha and RII were calculated for the level of awareness of sustainable construction practices and barriers to adoption of sustainable construction. Transcripts from the interview were thematically analysed using NVivo. The findings showed that the industry practitioners have above-average levels of awareness. Sustainable construction practices that respondents were most aware of was reduce, reuse and recycle. Respondents were not as aware of newer sustainable practices such as digital twin. Surprisingly, the most prevalent barrier was not cost. According to the respondents, the most prevalent barrier was a tendency to maintain current practices. Many real-life experiences are documented in this research. Insights into current practice in the industry and key barriers to adopting sustainable construction are identified. Addressing these barriers could improve the adoption of sustainable construction in the UK.