Long-term access to lifecycle data is key to a successful transition towards a circular built environment. However, the underlying technology often remains centralized and risks becoming inaccessible over time. In this paper, we investigate whether decentralized access methods using Web3, i.e. blockchain and decentralized data storage protocols, can help to mitigate this limitation. We implement Web3 data access mechanisms for a material passport with both a role-based and a token-based smart contract. Initial results suggest that Web3 offers a promising approach to data access over the lifecycle of a built asset - but only with careful design choices.