Purpose: Taking the perspective of a start-up company, the purpose of this paper is to analyse resource renewal in heavy business networks. Design/methodology/approach: The theoretical framework is based on the Industrial Network Approach and, especially, the resource interaction framework, business network settings and studies of starting up in business networks. The basis for the paper is a case study of a start-up in the Swedish wind energy context. Findings: Resource renewal in this case means replacing one resource, having implications for the resource interfaces in the three business network settings. Research limitations/implications: The paper contributes to the area of studies of starting up in business networks by identifying a distinct form of resource renewal in heavy business networks enabled by development of resource interfaces in three business network settings. Practical implications: Managers in start-ups as well as established firms need to interact to create and develop the resource interfaces that are needed to achieve resource renewal. Resource renewal not only is in the hands of start-ups but also requires interactive resource development with various collaboration partners. Originality/value: This study takes a start-up’s perspective to resource renewal of heavy business networks and analyses heaviness based on resource interfaces in three business network settings.