There are now several implementations of multi-user virtual environments (MUVEs) that have produced evidence of their educational validity. These implementations, however, do not make full use of the educational possibilities offered by MUVEs – namely the potential for students to learn through design and construct of artefacts within the virtual environment. This paper outlines a design-based research project that aims to implement and evaluate a MUVE that focuses on student design and construction of in-world artefacts. The discussion covers theoretical groundings, the challenges of construction and outlines a progression of activities that meet these challenges. An initial pilot study is described and reported.