102053'"Tier2Tier": A collaboration interface between construction main contractors and their supply chain specialist sub-contractorsClosedCollaborative R&DInnovate UKIt has been recognised that the benefits of BIM will not be realised without the collaboration of the main contractor’s supply chain: Tier 2 and beyond. There are significant barriers to this and it is unlikely that the CDE for Level 2 BIM is achievable without overcoming them. In response, Tier2Tier is a SaaS-based solution that will provide the Tier 2 specialist with an independent, controlled, bi-directional, cloud-based micro collaboration portal, allowing the 2-way transfer of validated information from tender through to final account. The envisaged service supports the goals of BSI B/555 Roadmap by facilitating controlled inputs, tender exchange, contract administration, automated payment transactions, change management, and COBie data transfer; all whilst minimising user expense. This collaborative project addresses the obstacles to participation of the wider project supply chain in the CDEs required for project teams to attain Level 2 BIM Maturity. This will be achieved by the re-examination of the business-to-business processes of tendering, invoicing, change management and payment, as well as using new “Big Data” and Social-graph approaches to manage multiple BIM projects.