Technology volition is the will to develop knowledge of, and use, the physical world to design products, processes and systems. The aim of this study was to contribute new knowledge of children's technology volition when they identify, build and improve technical constructions, and how teachers support this learning. Analysis focused on moments when children's volition was expressed in a construction activity. In total, eleven preschool teachers and 49 children, aged 4-5 years, from three preschools, participated. Data consists of video-recordings from four activities, two each in preschool A and B, showing children's expressed technological volition, as well as field notes about the teachers' preparations. Results show how differences among children's expressed volition is connected to their imagination of how materials can be combined to construct 'houses' and 'vehicles' from everyday objects. Building a house resulted in a focus on how to make the building solid and water resistant, and inspired children to learn about materials for different purposes in houses such as the floor, walls and an angled roof. Building a vehicle encouraged children to talk about speed, movements and fuel. Results show how children indicate and express their discernment of how materials are combined to create constructions, and how they discover ways in which materials change during the building process. For some of the children it was difficult to see the potential of a material other than its original use, while others used their imagination to find opportunities to use materials to make new objects.