The EU directive 2010/31/EU – created to address challenges of global warming and energy dependence – sets goals to reduce CO2 emission levels by 20% till 2020. As primary energy for households and construction industry is one of the largest manufacturers of CO2, a building material that can positively impact both these industries is topical and as such is tested in this paper. A lime-hemp concrete (LHC) is a material with negative CO2 balance, but is widely used only in low-story wood frame buildings and made on site. To achieve the goals set in EU directive a more industrialized product, that can also be used in insulation of existing buildings is needed, so methods of LHC slab and block manufacture are tested in this paper.