The construction sector accounts for a yearly 30% of the green house gas emissions in a global scale, while 24% of the total material extractions are used for building purposes. This thesis addresses the problem of sustainability in construction through an attempt to influence designers to make more environmentally friendly choices with regards to building materials. The objective of the research is to develop an application, as a decision-support tool starting from the early design phase, based on the environmental impact of the materials used in a building project. The followed approach includes integration of environmental impact data and Building Information Modelling (BIM), enabling automation in calculations and visualization of results. The integration is implemented using Semantic Web technologies and structures, as an attempt to apply Linked Data. An embodied impact database of building materials is used, while necessary information for the assessment is retrieved from the Industry Foundation Classes (IFC) model. Both information sources are converted into Resource Description Framework (RDF) datasets, based on the development of related ontologies. Information retrieval and RDF conversion is done with the use of Python programming language. These datasets are linked to each other through application of SPARQL Protocol And RDF Query Language (SPARQL) queries, for the estimation of the embodied impacts of materials existent in the model design. The implementation is incorporated into a user interface, creating a simple tool, able to calculate the embodied impacts of the materials in a model, visualize the critical components in a 3D environment and export the results into table format. Syntax validation, model case studies, calculation verifications and a reference literature study are employed in order to validate the tool in practice and theory. The conversion of the environmental impact dataset as Linked Data reveals the benefits of interoperability, data extensibility and efficient data consumption through employment of Semantic Web standards. The integration of Building Information Modelling and embodied impact information enables automation in the calculation process and exposes the potential of object oriented design towards sustainability.